After a couple of months looking, reading and learning about home made CNC machines, I started cutting out my 1" MDF machine today.

As I found other guys threads so interesting and useful I thought I would complete a build diary myself, and if a new person gets one piece of information out of it for themselves then it will be worth while.
Decided my first machine would be the learning platform and I will use simple construction and electronics.


My mate brought his Circular saw with a new MDF cutting blade and we cut everything out lovely and square.

The base is 36" wide x 33" deep, it has a fixed gantry with a table size of 24"w x 16"d.
I think I should have about a 20 x 12 cutting area.

I am using 1" dia stainless tube with a ground finish for the rails and bought a load of abec9 bearings on ebay.

I have three steppers, 1A, 1.2A and a 1.35A all unipolar nema 23 size.
Came across extremly cheap driver board from http://www.kitsrus.com/ (although I bought mine from the UK distributor.)
The K179 unipolar driver board kit was only £9.95 works great had my motors on the bench last night buzzing away.
The board has a manual control of speed and direction so is great for setting up without a pc connected.

Going to use a ATX PSU at 12v and some 6R8 resistors.

I do have some nice new in the box vexta 266 127 ozins motors that I bought from a guy, but I intend to keep them for the next one !

Don't have any fancy cad drawn plans of my machine all on bits of paper. I will see if I can post something to let people see the design.

All for now.

Can't wait to see how it comes out! Keep us posted.

Looking forward to seeing it. Good design for a first machine. Moving Table is simple and acurate. Also nice size.

Eric

Thanks for the replys.

Not having figured out how to draw with Autocad yet I done this in - Don't laugh ..... MS Word.

I'm one of those guys that does everything in word.

Hav'nt drawn the Z axis, but you will get the idea, actual machine will be rounded in places, but that is more difficult to draw !!

Might use some linear slides for the Z if I can get them at the right money, if not I will just go with the same pipe idea.

Hopeing to have it together (minus pipes) like this tonight.

http://www.esatclear.ie/~xair/my cnc.jpg

Only just figured out how to post an image, thought you could just upload it to the forum.
The FAQ don't have much info on how to do this.

You can upload it. Click "browse" which is left of "attach file", then browse for the picture.

Eric

I never saw a browse button, only thing was a IMG button then I typed in the address of the file I uploaded to my web site.

That was the problem...it seems to want a picture from your local hard drive. It actually uploads the image onto the server, and hosts it locally.

-- Chuck Knight

Look at the bottom under your message (while you are posting a reply). There is "attach file" and "browse".

E-man

what is the difference in the abec bearings, on Ebay I see
abec-5, abec-7, abec9???

Look at the bottom under your message (while you are posting a reply). There is "attach file" and "browse".

Eric,

This is always the confusing part for a new poster. You will not see the "attach file" if you use the "quick post" at the very bottom of each thread. You must click on the small button at the bottom of the last post's message that says "Post reply" Then you will be taken to a new screen with all the bells and whistles :D

Yeah I see it now Eric don't know how I never seen it before !!

Anyway, been out in the workshop all evening/night (midnight here now).

Got the two end rails and the gantry sides and front screwed onto the base.

Takes a fair bit of time getting it all marked out, and drilled accuratly.
I have a vertical drilling guide for my cordless drill (like a plunge router idea) so I was able to get all the holes nice and streight.

Decided to go with the tapping idea.
As I was going to use 6mm metric bolts I found the best drill size for the mdf was 4.8 (3/16").

As I drilled each hole I dropped a AN3 (3/16") bolt into each hole to keep it square.
I then drilled out the base 6mm and countersunk the holes for the allen head C/S bolts.

I tapped each of the holes, using a machine tap in a slow cordless drill and it worked great. I then ran thin cyno down the holes into the threads.

So this is the stage I am at. Need to turn up some inserts for the ends of the tubes (rails) and make the adjusting blocks.

What is the best material, I was thinking about nylon or similar, don't think even the 1" mdf will stand up to it.

Don't know a lot about the bearings but I do know that abec 9's are water proof, 7's are classed as sealed and I would think that the 5's are probably just shielded.

I have both 9's and 7's and the 9's are definatly the better.

The different ratings have nothing to do with seals or shields. And I'm pretty sure that none of the abec 9 bearings (skateboard bearings, anyway) on Ebay arer waterproof. The difference is, the higher the number, the tighter the tolerances are. Generally, if you're gong to use them on some type of tubing ala JK, it won't really matter all that much. But if you can get abec 9 bearings on Ebay for $5 or so, no reason not to get the best if you're paying the same price.

Gerry

What gerry said about bearings is correct.

Nice job so far AirX. Use Plastic, PVC, or aluminum for the adjuster blocks. MDF is not tough enough. I have heard you can buy a cheap plastic (nylon?) cutting board from wallmart that will work for those and some other plastic parts. About 1/2" thick.

E-man

Got my table made up today with the angle down each side and the bearings fitted.

I bolted the angle to the MDF with 6mm Stainless Hex bolts. Four underneath and three on the side.

Surprising the time it takes, just to mark and drill the angles, so as to get the correct distances for the bearings, as they sit on the rail at 90 deg to each other.

You can see in the pic the black engineers marking ink (well a large permant marker !) used to see the lines on the alloy as I marked everything with the height gauge.

The time I have spent on getting everything as accurate as possible I started to think I should have went with the all aluminium version now, but I am determined to build a MDF machine, as simple and cheap as possible.

The alloy machine can come later.

Got my end plates drilled as well for the tubes (rails) and I am picking up some 25mm (1") nylon tommorrow to make the "four jaw chucks" for setting up the rails.

My local steel stockist cut up some 2" x 1" box section to my requirements today, so I can start welding up a frame/table next week to set the machine on.

Fitting the stepper and lining up the drive screw has got me thinking.
What I was going to do was mark a spot as accurately as I can on the drive plate under the table, and then drill a larger than the drive screw (5/16") clearance hole.
Fit my drive nut to the drive screw then bolt this to the plate, does this sound correct ?

What would be the best method of connecting up the 1/4" shaft to the 5/16" drive screw. ?

Forgot to add in last post, the bolts I used for the bearings were socket caps (as you can see), 8mm x 40mm but the good thing was they had a plain shank of approx 8mm long which was a perfect surface for the inside of the bearing.

I fitted a thin Stainless Steel washer each side of the bearing then tightened up a S/S Nyloc nut against it. No play or slop at all.

The bolts are a bit long, and I have them fitted with std nuts temporarily at the moment.
I am on the look out for a S/S version of the bolt, about 10mm shorter, but might be harder to get the plain shank.
Good thing about stainless is you can cut it without it rusting !!

Looking Good!

If I might ask.....Why the stainless steel on any part?
Seems like an unnecessary cost.

"Fitting the stepper and lining up the drive screw has got me thinking.
What I was going to do was mark a spot as accurately as I can on the drive plate under the table, and then drill a larger than the drive screw (5/16") clearance hole.
Fit my drive nut to the drive screw then bolt this to the plate, does this sound correct ? "

What I did was mount one side and run the axis down to the other side to match it.

"What would be the best method of connecting up the 1/4" shaft to the 5/16" drive screw. ?"

If you referring to the motor to the drive screw I gut got some reinforced rubber tubing with hose clamps.

On mine, I got some reinforced air tubing, and actually tapped the 1/4"ID tubing with a 5/16" tap.

I screwed it in, and then slipped in the 1/4" shaft -- some worm clamps to hold everything tight, and it worked great.

Or, you can get some of those flexible couplings from McMaster-Carr...they have a standardized mating connector at the center...the two ends can have different sized couplers.

-- Chuck Knight

The reason for the stainless is I hate rust, being from an Aviation background it is always a no, no.

The climate in Ireland would be much more damp/moist and even in a workshop untreated steel items don't stay shiney for long.

The other reason is I generally have loads of stainless nuts, bolts washers about as I use them in my buisness all the time.

Not much difference on cost, I can get 100 M6 nyloc nuts for only about €2 more than standard ones.

Great idea chucknigh, I will use that. Can't believe the stuff I am tapping these days !

On the tapping front, Yesterday I could'nt find my 6mm machine tap (located later in my pocket !) so I used a standard hand tap as I only had one hole to tap.

Well Massive difference the quality of the tapped thread was nothing like what I got with the machine tap.

The reason I went with a machine tap from the beginning is I know from experience, if you want to tap without having to back off to break "the chip" like normal, then a machine tap is the way to go. The flutes are designed to take the chip/swarf (in the case of steel) out in one piece, so you can go streight in and streight out, perfect for tapping with a cordless drill.

So my advise is, when tapping MDF get yourself a machine tap rather than a hand tap and you will get perfectly tapped holes everytime and easy to using a cordless drill.

Thanks Xairflyer, for the tip on "Machine Taps".

Would a machine tap also reduce the possibility of tap breakage when tapping alum? I'v broken a few taping alum, seems the chips stick together and jam, even when backing up ever so often.

Hager

Mr. CHips, You might want to use Tap Magic cutting fluid for Aluminum. It will solve your chip sticking and jamming.

xairflyer, When screwing MDF together I think the best fastener is a confirmat screw. Here is a link that shows how one guy uses then in cabinet work.
http://www.norrod.com/shop/screws/
You don't need that fancy drill bit, but you need a clearance hole (8mm) for the the shoulder and a pilot hole (5mm) for the threads.
This eliminates the tiring tappping of MDF and holds fantastic.

Yes I have used these before they are common to flat packed furniture you buy at DIY stores.

Tapping should not be tiring if you use a cordless drill !!

The K179 unipolar driver board kit was only £9.95 works great had my motors on the bench last night buzzing away.

good deal those, wish I had seen those before I started my homebrew version. its pretty much just the cost of the parts...

Originally posted by buscht
Mr. CHips, You might want to use Tap Magic cutting fluid for Aluminum. It will solve your chip sticking and jamming.

Tap magic is incredible stuff. Personally i usually back the tap all the way out of the whole and blow it out every quarter inch or so with aluminum

I spent the last week cutting and tappin 4140 and was amazed at how well it actually tapped, so much easier than i expected

Mr Chips,

Machine taps work great in all materials, and by their design, are not meant to clog up. But a tapping fluid like buscht mentioned is always recomended as well.



Davesaudio,

You should also look at the K109 kit it uses the UCN5804 chip and has half step as well. £14.95stg.
It is Limited to a 1.25A motor in it's out of the box setup.

I have ordered one to play with, as I want to build a pan mount for my CCTV camera.

Started making up my 4 jaw chucks today for the rails.

Only material I could get (without having to wait a week) was 1" nylon. Sorry I never waited !!!

I decided to drill out the clearance holes for the 1" tube and used a 1 3/8" hole saw.
Nylon is a pain to cut at anything faster than you can do by hand.
It heats up so fast, I was cutting at the slowest speed on my drill press, and it still kept heating up, clogging the cutter, even the coolant was bubbling with only small cuts.

Eventually got four holes cut for the x axis blocks and then I tried to cut them into 3" squares (as I left them in one piece for easier drilling) I decided to use my jigsaw as I had broke the blade in my bandsaw last week.
Tried all different pitch sizes of blades and all it did was melt !

Ended up Cutting it with the hacksaw which cut it fairly well and easier than I thought.

Note: Best thing to cut nylon is a hacksaw, bandsaw would be ok to if you have access to one.

After all that work I Still have to clean them up, and probably still won't get that good of thread when I tap them.

Would not recomend the use of standard nylon, especially that thick, Delrin is a far better material.

I could have made them up in 1/2" alloy plate in half the time, but I did'nt really want to mix alum with the wood if possible.

I am going to make some out of 1" MDF for the y axis just to put to the test. I think with the great thread my machine tap makes, along with the thin super glue I will have just a good of job as the nylon ones.

Time will Tell !!!!

The CYa will help a lot with the threads. It's a trick only a model airplane guy knows!

Eric

I think being a model and full size flyer is what gave me the motivation to build one of these machines.

I can see lovely ribs etc being spat out, as fast as I can stick them together.

I want to build a 1/4 scale R/C model of the aeroplane that I Distribute and fly.
The wings are tapered and swept back so it means a lot of cutting by hand.
This will be my first project when the machine is up and running.

I have a lot of little things I want to make for the full size version's that I have to make by hand now.

xaeroflyer,

You have a beautiful flyer in the picture. Do you have the plans for it? I'm interested in building one myself.

It is only available in kit form, we both sell kits to customers and build for them.

Construction is all aluminum tubing and the covering is Dacron (polyester).

Got my steel framework made up to sit the machine on.

Made the whole thing out of 2" x 1" box section, need to paint it now with hamerite.

Not been too happy with the nylon blocks for the four jaw chucks, firstly because of the work it took to make them, and second because I am not that keen on the finish or thread quality.

Decided to make some up out of 1" mdf to try out and I am really pleased with the result.
I cut the clearance hole in the middle, with a 1 1/4" flat (spad as we call it) wood bit, and the finish of the holes is lovely.

Made big discovery on the tapping front.
I had this flash of an idea lying in bed, and decided to try tapping the holes with a Roll tap.

The difference is (hard to explain) the tap dos'nt actually cut a thread, it makes the thread by squeezing the material into a thread as it goes, so instead of material being removed (swarf) it push's it into the last thread.
These taps are normally used for tapping holes in extrusions punch out of a piece of material in order to give it sufficent thickness to actually have a thread. (a 1/8" thick piece of material would not have many threads, but this can be doubled or trippled by extruding it.

You could'nt use one in normal circumstances for tapping steel as it would jam or break, but wood and especially MDF is perfect for it.

I put it to the test and the threads are actually HARD, this is due to the squeezing of the wood to form the thread.
With the thin cyno, and then re tapped again after about 2hrs (won't get bits of glue stuck on your tap, if you leave it a while to harden) The thread quality is that good, my mate thought I had fitted inserts into the mdf.

The moral is for tapping MDF you want to get your hands on a Roll tap.

So I am scrapping the Nylon 4 jaw chucks and making them all
(x and y) out of MDF, as you can see from picture I have drilled all the holes in a 9"x6" piece ready to be cut up into 3"x3" squares.

The nylon block dos'nt even look as good !

"Roll Tap" never heard of that one. But the principal sounds very sound with MDF. Is this tap available in the US?
I made my first srt of blocks out of a thick cutting board and it was a mess cutting them the material wanted to melt and difficult to clean up. Finally decided not to use them and gang drilled the end plates. Put the base together today will find out tomorrow when I mount the movable table how far it's out. Hope they are parallel and level, time will tell.

Hager

I agree nylon/chopping board material, is a pain to work with, I milled up the sides of the blocks I cut, but not eveybody has a mill in the garage, so that is why I favoured MDF, as a test.

The name "Roll tap" could be an engineers term for a "fluteless tap" try that name and see how you get on.

They are in my RS catalogue, not that cheap as they are a specialist tap, but for tapping MDF brilliant.

In the RS catalogue they state "they produce threads not by cutting, but cold forming material displacement"

I'm using Forstner bits for all my holes... MDF and cutting board material. They leave a flat bottom hole too incase you don't want to go all the way through. The hole is a lot cleanter then the hole saw holes. I drilled these bearing blocks with them, and the holes they leave in MDF are incredible.

Ernie

Forstner bits have the bonus of making round holes as well, instead of the slightly oblong holes from a twist bit. Bearing blocks look great. What are the step sizes? 7/8" and 3/4?

yea they are 7/8 and 3/4 the bearing isn't really tight in there, but there isn't much slop either.

Ernie

should be tight enough once you get your washer on there. Another idea...use a fender washer that is just small enough to grip the outer race of the bearing, and drill two holes in the edge to mount it.

CMT makes 22mm forstner bits, for about $15. That is what those bearings are, right?

Gerry

Looking at theses things I don't really think anything needs to be done to them as far as the tightness. I do need a drilly press though, to make the holes straighter. I had a freind that had a small mill he wanted to sell. If I can find his number and he still has it I'm gonna buy it.

I have been looking through various posts, on lead screw (drive screw) fitting and I can't seem to figure out why a thrust bearing arangement is used for the end of the thread.

I was going to mount a rod end type moveble bearing (to allow for any miss-alignments) to the end plates and just stick the threaded rod (5/16") through it.

Can anybody explain what I am missing, or not considering ?

The thrust bearings keep your leadscrew from moving back and forth when it accelerates or decelerates against the table load. I use 1/2"-13 threaded rod and 1" delrin nut for drive. The rod is turned down on my lathe to the ID of the thrust bearings,and sandwiched, I did not use a tensioning arrangement. Tensioning the leadscrew would have helped a bit with whip, I get a bit with rapids, when the table is at far travel. I did leave about 3/4" of excess rod out the end of thrust bearing, enough to thread with a die for a tensioning nut/washer arrangement if I feels its needed.
Steven

I hear mcmasster-carr has thrust bearings with 3/8" ID and a flange on one end. Haven't checked it out yet but they prolly do. May even have different sizes.

Got the X axis/table all setup last night. Takes a bit of time to get everything right.

I first got the base of my machine on it's stand perfectly level in all axis, then set the table in and got the rails parallel (ish) so that the table ran freely with the side bearings touching at all places.

I then removed the table and leveled each rail fore and aft, then from one rail to the other, and back & forward, and back & forward as each adjustment effected the other.

I the checked the parrallel'ism with a large verner, then back to the level of the rails again !!
Eventually I got it that I was fairly happy.

Re fitted the table and checked it for level on the rails. Only one bearing was out, a bit too low, which caused the opposite bearing to sit above the rail i.e. not touching.
Looks like it was worth while spending the time marking out the bearing positions on the angles very accuratly.

Turned up an insert out of nylon to fit the ends of the tubes, just to stop the adjusting bolts from disforming the tube. Not that the stainless pipe I used would be easy to squeeze, but I though it would look better too.

Just a word of caution.
MDF is very dense but it doesn’t have very much linear strength to support it’s self and will sag and flex very easily over relative short distances. Neat looking table just be sure you have a couple of supports under the machine to keep the base plate flat.
I’m building a movable machine also and the table is 24” wide. When I installed it, it was flat, but just over a few days it has started to sag just under it’s own weight. Mea by it’s the humidity here?
I found a used piece of 1” delrin and will replace my table with it. Before I found the delrin I was thinking about adding some kind of metal brace for added rigidity.

Torsion Box
http://www.diynet.com/diy/shows_wwk/episode/0,2046,DIY_14350_26946,00.html
Another way to eliminate the sag would be to make a torsion box type table. But this would make the table thicker.
Anyway it’s a thought.
Hager

AirX,

Slot the hole in the alum. angle so you adjust the offending bearing and retighten.

E-man

Don't know about \delin, but UHMW is similar and flexes and contracts readily with changes in temp. Why not get a cheap piece of aluminum angle and cut into pieces to reinforce?

Thatdelrin is probably as expensive as aluminum plate .25!

Don't think I will have any sag problems, the MDF is 1" thick and it is sitting on a frame of 2"x1" steel box section with a support every 9".

Balsaman that's what I done to adjust the bearing.

The Delrin was free. It is 1" thick and has lots of 1/4" holes, it was to be a vacuum table in a lab but they made a mistake during machining and it was trashed.

Nothing to loose, had only to cut 1" off the width for it to fit my table. And I could not make it flex.

Xairflyer,
You wont get any MDF flex on that table.

Hager

Ok, so the delrin will be on top of the MDF? What I was talking about was unsupported lengths of plastics warping like crazy, but if it has an MDF backbone that it is screwed to it should be fine. But why use the delrin if in fact you are keeping the MDF too?

Sorry I didn't make myself clear. I removed the MDF table and replaced it with a piece of delrin that was 1" thick.

Are you sure this material will "warp like crazy"?

It is really rigid, I could not make it flex any by placing one end on the floor and the other end on a 2X4 and standing on it. 210Lb. The 3/4" MDF could be flexed by pressing on it, without standing on it.

I'll try it and if it doesnt work out, I'll cut it up and make antibacklash nuts out of it. Can get alot out of a piece that is 1" X 24" X 30" even cutting around the holes.
Hager

But then you would have to build more machines! Like I said, I don't know about delrin specifically, but UHMW which is similar is very thermal sensitive in large pieces. Anything more than about 3/4", and it swells and contracts. I have a 2" by 3" by 3ft piece, and it is very solid, yet always has a different profile! Anyway...just my two cents.

I don't know if Delron warps ut UHMW sure does.



Garry

Have the x axis motor fitted and the table moving under it's own steam !!

Tricky job to get the Delrin nut/plate fitted under the table.

I first screwed a 1" x 2" x 5" block to the bottom of the table in the middle. I had already worked out that the lead screw would be approx 1" below thw table so I drilled a 13mm (1/2") clearance hole to allow for any slight misalignments.

I made a delrin plate (no antibacklash for now) and pre drilled two holes in opposite corners for screwing to the support block.
Screwed on the delrin nut, and refitted the table.

Screwed up the plate until it came in contact with the support block, and very difficultly (as there is only 2 1/2" under the table) managed to clamp the delrin plate to the support block.
I then removed the screws holding the block to the table from above and lifted the table out of the way.

All I had to do then was unscrew the threaded rod and drill my holes.
A tricky job, but it was worth it as everything runs nice and true.

I rigged up my test driver board and I am not getting much speed, with a 3.9v 1.35A motor running on 12v with two 6R8 res (6 wire) turning a 8mm (18tpi) screw, the best I get is 10" min.

How can this be increased, I was thinking of changing to 10mm or 12mm all thread ?

Will a larger 2A, 3.6v, 127ozins torque motor go any faster ?

Does anyone know how to attach more than one picture in each meassage ??


Started fitting my Y axis

Originally posted by xairflyer
Does anyone know how to attach more than one picture in each meassage ??



This site can't do that right now but the new one will.

Need more voltage for more speed. What driver board are you using? 10-12" is normal for a 12 volt supply.

Eric

check out Steve Manzer's site here, he is getting double that speed with 20tpi rod.
http://www.angelfire.com/ego/stevenmanzer/CNCMachines.html

The driver board is the K179 kit basicly the same as the piker.

I hgave altered the value of the pot and limit resistor (used for manual control, not connected to PC) and when I go too far, the motor just buzz'sssss

I assume the motor can only go so fast.

Does the speed vary in motors ? I am wondering if my 2A 127 ozins vexta 266-2b motors will go any faster.

can't find any numbers on the website, but my 80 oz/in motors are capable of 120 rpm so I can't see yours being slower. Check that your screws are not binding at either end of travel, as that has in the past caused just buzzing with no turning. You'd have to turn 400rpm to get 20 ipm, right? Huh...don't know how that math works out then, cause Steve Manzer is getting 20ipm and I think he is useing the the same cheap motors. I'll do some reading on his site today, post later.

Higher oz/in does not mean faster unless you go higher VOLTAGE powersupply. 24 volts with the right resistors will double your speed.

Trust me on this one.

Oh, and don't worry for now about speed. Get the machine going first.

Trust me on this one too.

Also, I am not sure how/if you can accel with the setup your using, but that is a factor as well.

Eric

Balsaman is right, if your drive nut is not causing lots of friction the problem is in your drivers. Get a chopper board, run it at 30V and amaze yourself at the speed you get ;)

John

Now I know that 10" min is normal for this setup I will stick with it. I thought I was doing something wrong.
I don't want to fit a different driver board or bigger power supply, the idea was to make this machine as cost effective as posible to prove the principle to myself.

If I can speed it up a bit with 10mm threaded bar then I might change to that.

I will go with Xylotex board and proper drive screws and all the bells and wistles for the all alloy machine I will build next.
First I want to understand how to get this one setup.

he driver board is the K179 kit basicly the same as the piker.

I wonder if the mosfets are being driven hard enough by the cmos logic at 5volts...

do the mosfets get warm(er) when the stepper buzzes?

the z44s are sufficiently hefty...

Not sure if they get warm as I adjust the pot, until it starts to buzz then back it off slightly so it is at maximum speed.

I measured the 100k pot at this setting and it was about 900ohms, so I increased the in series 1k limit resistor too 2k2 so I can just screw the pot the full way now, just for practicality.

I am using this board (K179) as a stand alone at the moment just for testing, a 4093 is used as a pulse generator.
The values of the pot and series resistor shown in the documentation have been changed to values above.

As I know full speed is a pulse frequency generated by approx 1k9 with the cap fitted (1uf) I will try a 4k7 pot in place of what's there and adjust that to the optimum, that way I will be able to get the motor at it's optimum speed before it buzzes.

Seen somewhere diodes added from each side of the coils to positive, so I decided to add them in and see what happens.

I connected each one first by mistake to the 12v (bypassing the dropping resistors) and the motor ran at the same speed by sounded very rough.

Connected them then to the other side, matching the centre taps, as I am using two resistors (just in case it would make a difference) and the motor ran very very slow.

Realised then afterwards that fitting diodes like this was really for protection of transistors and as I am using fets, it just made things worst.

Any views ?


NOTE I have not shown the diodes on the circuit below, I just attached it to show the ouput.

Been working on the Y axis, as you can see from the pics I used angle and roller bearings again. In order to get the angles nice and square I milled/routed two slots for it to sit in.

Had to also mill out some clearance for the nuts.
Set my rails up first like the x axis, but this was a mistake as I then had to make the spacing piece to fit the setup of the rails, which meant machine the spacer 58.8mm !

Should have made the spacer a fixed demension i.e. 60mm or
2 1/2" and adjusted the rails to suit.

Also got the rails perfectly set up, only to realise, I needed to remove one of them to fit the y carriage !!
Rails needed to be fine tuned again anyway - you learn these things as you go !::D

Great carriage design...how is the flex in the steel rods though?

The rails are 25mm (1") Stainless Steel tubes with a 1.5mm (.060") wall and are very ridget (can never spell that word).

If I push down on them, I can get them to flex about 0.2mm (.008"). I am going to fit a support block under the lower rail and above the top rail once I get everything setup.

Are your bearings pre-loaded into the tubes? Just curious, as it doesn't look as though you have any adjustment for the tubes themselves. Oh...its rigid. Gonna go for now...uncle Bushmills is calling my name!

If you about 15 posts up you will see the four jaw chucks fitted to the side plates.

Messed about with the driver board, and now have 12" min with the 20tpi screw.
Going to stick with that now until I get the machine running, will then try 10mm and 12mm threaded bar.

Working on the Z axis, and decided to have a go at making my own bearing blocks for these great simplicity bearings from Pacific.

Main concern was accuracy, as I did’nt want them binding. Decided to go with a mixture of mdf and nylon.
Made the two end plates for the 12mm shafts out of mdf and milled them perfectly square. I put one on top of the other and then used a 12mm milling cutter that I under sized slightly to drill the holes. I clocked up the spacing on the cross slide vice, to have a reference for the bearing blocks.
The 12mm shafts were now a rubber hammer tap into the mdf end plates.

The simplicity bearings have an OD of 22mm and in the manual it shows fitting ‘O’ rings to the groves to allow for slight misalignments which I thought would suit here.
The hole in the bearing block is oversized 0.2mm to allow for this, so I modified/ground a flat wood bit to 22.2mm. These are great for cutting accurate holes.

Made up the two nylon bearing blocks and drilled them like the end plates, with the exact same centers. Holes came out 22.22mm (.02mm oversize less than a thou) I was happy with that.
Bearings were a nice tight fit in the blocks. As I used 25mm nylon I milled down to 20mm to allow for the retaining circlips.
I can see now how the ‘O’ rings work, it is a really good idea, keeping to the manufacturers sizes would be important though.

My two blocks slide really nice up and down the shafts, I still have to fit the router holder to the blocks.

Really glad I went this route, simplicity bearings are cheap and are designed to run on any type of shafting, provided it is true. The cost of the Bearing housings put me off before going this route, but reading mikeschn thread got me thinking.

And the Z axis itself, temporarily fitted to the Y


Note. Nylon block between bearing housings is only a temp spacer.

Looks soild, that should work fine.

Are you going to have more space between the bearings when the spacer is removed? I would be concerned about flex in the tool carrier without enough space.

There won't be any movement, this is one of the reasons for going with this type of slide.

Originally posted by xairflyer
There won't be any movement, this is one of the reasons for going with this type of slide.

Wouldn't the unsupported pipe/rod be the source of almost all of the flex in this configuration? In that case, you would get less flex by putting the bearings further apart.

Arvid

I was reffering to the vertical distace between the bearings. Seems to me that with the mounting plate on there, the shorter distance will act as a more effective fulcrum, in a 20,000rpm lever. This is why I have been trying to caution people against too long of a z-travel for their first machine. The z is already the hardest part to build (in fact when I am trying one of my new ideas, I usually start with the z, then y, then x), and more travel makes it harder. IMHO.

Picture is a bit deceiving, and spacing of the blocks is not as is, it was the first bit of nylon I lifted !

There are 10" between the end plates, I will space the blocks about 5", with the limit switch's there will be about 4 1/2" travel.

Arvidb is right the Y rails are the weak spot in my machine. I have suport blocks already made up for bottom and top of the Y rails. Don't intend fitting them until I have everything where I want it.

Originally posted by xairflyer
*snip* There are 10" between the end plates, I will space the blocks about 5", with the limit switch's there will be about 4 1/2" travel.

Arvidb is right the Y rails are the weak spot in my machine. I have suport blocks already made up for bottom and top of the Y rails. *snip*

Since my last post was a bit unclear: I was too referring to the vertical distance between the bearings, not the distance between rails.

If I understand your description correctly, maybe the end plates will be spaced far enough apart, and the travel will be small enough, for you to be able to fit a support at the mid-point of the Z rails, in addition to the end supports? If you could find room for this, it would stiffen things up considerably.

And if not, and if you are unhappy with the amount of flex when the machine is finished, you would at least have the option of sacrificing some Z travel to get more stiffness. It all depends on what you are going to cut. If balsa I guess it won't matter!

Arvid

I don't think the Z axis rails are going anywhere, they are hardened ground rods and being only 12" long the best deflection I could get by really forcing them was .1mm.

The mdf is 1" and again over this short distance it is very ridged.
Any flex or movement is going to be in the Y axis, I will need to make my support rails, very accurate.

Sounds like we are all on the same page! BTW...didn't say it before, its looking really good! Can't wait to see it finished and movin'!

Still working on the Z axis, I have scrapped the idea of using the leadscrew/motor combo I got from www.manufacturist.com
due to the low torque of the motor.

Decided the Z could do with a good motor as it does have to lift the z axis and the weight of the router, so I am using one of the vexta 127 ozins motors I had been saving for no. 2 !!

I am using 12mm threaded rod, so I turned down the end to a nice fit in my bearing in the end plate, and drilled the other end for the shaft of my stepper.
The stepper had a hole in the shaft so I done the same in the all thread and fitted a roll pin to secure it to the shaft.

Tapped the 1" nylon block I made for the simplicity bearings with a tap made from the all thread, and it works good.

Need to start painting as I don't want to take this apart again.

Pics to follow, camera batteries were flat !!

Sounds good! That lead screw would work well for another project once seperated from the motor. It is teflon coated steel, and really nice! It is very unfortunate that the motors are not very strong. We think they were origionally used horizontally, as they seem to work much better that way. Can't wait to see those pics!

I am going to keep the stepper/leadscrew for a small pcb machine I am going to build, it will work ok for that.

Here is some pics.
I am away for a week so the work has stopped.

Nice job!

Eric

Yes very nice. Very good quality work you are doing there..:cheers:

I have became a massive fan of the flat wood bit. The skate bearing used in the end plate is 22mm OD as you know, so I ground down a 22mm flat bit to about 21.75mm.

I then had a squeeze fit in the end plate for the bearing.

Great bits these, you can as accurate hole as you want with a little of regrinding !

Been away for a week and could'nt wait to get back to finish my machine.

Spent yesterday completing the Z and making a clamp for the router.

The z axis works very well, the 12mm all thread lead screw suits it perfectly, with the 127oz ins stepper.

Still think the Y axis is the weak link in the machine, I am going to make supports for the rails and see how it goes.
I will probably change them down the road for 20mm (3/4") shaft and Simplicity bearings like I done for the Z.

Pictures below show the Z temporarily fitted to the carriage as I am going to paint it before I bolt it up for good.

Also pic below shows the router spinning with the lights ON !!

I dont know if I missed it up thread but anyway.
What are your expectations about precision?

Won't know for certain until I reasemble it all this week as I have been painting. (a lot of painting)

Time spent on the setup will determine how good I get it, If I can't get it within what I expect for this first machine then I will change it. Would expect to get it as good or better than what is normal for rollar bearing machines.

xairflyer,
that machine looks like the dogs 'whatsits' have you drawn any plans up?
Very very impressed at the design, if you do have any plans/drawings/ sizes I would be very grateful.
Keep up the excellent work
Gus

I do intend to produce a plan, as it is difficult to get any outside the states.

As an update, I have stripped the whole machine and have it all painted. I am in the middle of building it up again, and setting up the rails etc.

Glad I decided to dowel most of it as it has made the reassembly much more streight forward.

xairflyer
daft question but here goes.
The router is just plugged straight into mains and is not going to be controlled by P.C.? You plug in to switch ON and unplug to switch OFF!
Gus

Yes, but some boards also have a means of controlling that as well.

Yes any type of bits at a good price in the uk is a pain. The price and getting plans steppers and linear bearings etc well every time i look at the US theres loads and at good prices. Keep up the good work on your mill i am just about to start mine.
Mdf is what ill have a play with. I am only working to A4 size for pcb drilling. Iwas thinking of 400mm across and 600mm towards me on the bed in 16mm bar and the same sort of bearing you are using on the rails but slightly different way of using them.
Have some old type 23 70oz steppers 2.25 volts so should do the job. And kellyware software.

Glen

I am going to build a PCB machine as soon as I finish this one, I am already gathering up the bits !

I am interested to find out more on the whole making pcb's process with type of machine.

xairflyer,
I started cutting MDF today (how heavy is that stuff) and have got a similar design to yourself but I am using solid ground steal shafts bought from RS supplies (I got a free CD from them by sending an email) they have a lot of stuff on there that we can use including stuff like linear bearings, they also do steppers but they are very expensive. I was lucky and got given 4 100oz steppers but there are some electronic salvage yards that strip old machines and sell the bits out of them i.e. steppers etc try WWW.distel.co.uk.
I to will, when I have made this monster make a smaller router board (I plan to use this one to make the smaller one) and plan to use either a dremil or a dc motor for the router.
Best of luck and keep the pictures coming
Gus

Have a look at the self lubricating bushings from rs 243-9710 (20mm size) you can get them in a pillow block as well 217-9805 also the IGUS drylin range 20mm = 311-3480.

I used the 12mm 217-9697 for my z axis with 12mm shafts RS shafting is also not bad value 285-0396 is 1M length of 20mm it is about £22.

I might upgrade my y axis after I have things running.

A dremel will be OK but have you seen the one I am using from B&Q on special at the moment for £29.98 !!!

I posted a thread for it some time back

http://www.cnczone.com/forums/showthread.php?s=&threadid=2814&highlight=b%26q

Ill have a look in there tommorrow. I brought my leadscrew from them. Nice 8mm one from them 98 pence per meter.

Glen:D

I got 608ZZ for 50 pence each. Ahhhh it does pay to shop arround these are 8mm inside and 22mm on the outside. My design uses 30 ish. I brought 50 for that price...

Glen:D

I must say having looked at the router you posted it does seem to be a very good buy.
The RS stuff also has 'draw slides' and other interesting stuff that people have used for making there own tables with. Having had a look at a table made with these I was a little unsure but having seen it work (making pcb boards and small balsa parts) it does work very well. We used a vernier and found it good for 0.3mm (I kept rechecking because I couldn't belive it) the cutting size is around 300x300 mm with the z axis having 80 mm travel. The slight problem with it is the time factor for milling. A pcb around 250 x 200 takes a good hour and then sum however as my freind said IT GETS THE JOB DONE!
The total cost was around £120.00 which I thought was a very good buy, and I want one.
So many things to build, so that I can then get on and build other stuff!

Keep up the good work

Gus

Slides I was thinking of using were Igus drylin N they look very good and well priced example no. ns-01-27-06.

The B&Q router is excellent value I am going to but another one as I want to leave one in the machine, I find the flexible drive and the angle grinder so useful for other things, I don't want to keep taking it in and out.

xairflyer,
just back from B&Q with the router (yet another router mt wife asked).
I cant find stainless tube of good quality and diameter so for x & y axis I'm going with the 20 mm linear bearing shafts from RS and will be using the alluminium alloy housed linear bearings, they come supplied with a linear bearing and although not cheap will I belive produce a very good quality table (if I can keep the rest working to tolerance that is).
My friend with the pcb (draw slide version) router is using a brushless electric motor as a router (they are made for model electric aeroplanes) it is very quiet and very, very powerful. Its called an 'outrigger' because the outside rotates with the prop or in this case a collet. He uses a brushless controller and speed is from nothing to very fast but the cost is ALOT. He was lucky he had one lying around.
Gus

Can i ask a quick qestion to u as this is one which has been on my mind for a few days etc. WE put so much effort into the bearings either linear or like i am using 22mm skateboard bearings and the slides in my case from ondrives there ground steel bar. What the question is the we stick it on MDF for the bed etc. This cannot be truely flat. What is the error on this. Ive spent pounds etc even over a hundred on the metal bits. But then £9 on some mdf.

Whats your thoughts on this???

Glen

Glen,
I know what you are saying, I and everybody else must have thought the same. I am welding up a table which will also be a stand for the machine and it wll have supports underneath every 8" as long as I try and make everyyhing true then thats all you can do. MDF properbly isn't the best thing to make it from and we should be using aluminium or steel but as it was explained to me, when you have built this machine and get it working use it to make replacement parts from aluminium or steel. Or it it aint broke don't fix it. Both arguments are very valid.
I'm using MDF because others have tried it and they have had very good results but I will when finished try and make it better.
Cranky always says KISS and he is proberbly right.
Gus

yeah thats what i thought. Mdf o.k for pcb drilling but not so hot when milling metal or wood where the deepth has to be spot on.
Its all down to the length of what you are milling i suspect.

Glen

Glen,
my mate has just pointed out to me a simple way of making sure the beds is level. When you finished your router and its working have the machine mill the bed from 'home' to the furthest point away. With luck you will remove very little but if you do then you have removed the high points, if you remove 0.05mm all the way from 'home' to end then its flat! It might need doing every now and again.
Back to simple draw slides for a moment Milford Instruments Ltd do a 3 axis machine that uses them and its cutting area is X axis 185mm, Y axis 185mm and Z axis 160mm they quote a resolution of 0.1mm!
You can down load a manual off their website for this machine, check out www.milinst.com.
Gus

That makes sens... Mill itself...

Yeah the millford one is the one i first looked at but it didnt do A4 boards. In the end i went for kellyware software and the slides from ondrives have just turned up. Thought about going the draw slide way but thought s*d it and brought the rod. Got the stepper drivers from Quazar electronics and built those this morning. £9.95 a kit so £30 for the 3 motors. Will need to add some resistors but who cares.
Stepper motors i was given this end but might not be upto it but ill have to wait and see. Drill is a dremel £60 from argos but will look at b&q at the router and also going to get the mdf from them.


Glen

Glen,
interested by the kellyware software, where, who, how much?
Gus

http://www.kellyware.com/

About £50 ish. U can try it for free just download and if u buy he sends u a code.

Glen

Cheers Glen will check it out!
Gus

It depends also on the thickness of the mdf 1" actually 26mm is as ridged as hell, my base is 36 x 34 I have made a steel frame out of 2 x1 box.
If 1" mdf is well braced (end rails etc) and painted it will be ok.

RS do various different types of shafts the numbers I posted a couple of messages ago are the best value but still excellent quality.

26mm good call i have 18mm but will try to track some down.#
Missed out on the B&Q router deal southend have only ones at £54 ish.

Glen

Hi all,
downloaded the kellyware and am playing about with it, first impressions looks good.

xairflyer, I,m using the 20mm steel shafts form RS my tables cutting area will be 12" x 24" with a Z axis of around 4-6". Its design is a bit of yours and a bit of balsamans. What driver card will you be using for the steppers?

As for the next table (I know get this one finished first) it will be for doing PCB and have thought that I would design it with 'cardboard' so that all parts interlock and then transfer these shapes to the cad package and mill it from 2mm aluminium (cutting size will be around A4 size). Had a thought of using brass or copper and soldering the thing together but if done properly the aluminium could be simply epoxied together on the thin stuff and tapped and screwed on the thicker stuff.
This router would be a lot smaller but (hopefully) more acurate than the bigger one, hopefully.

Thoughts?

Gus

I'm using the k179 kit from quasar electronics for now.

If I was going to buy a commercial unit I would get the Xyolex.

Glen try B&Q online www.diy.com you can by it there as well

Cant seem to find it on there. Can you if so whats it under...

Glen

It is not there anymore, just comes up this product is not available, try another B&Q store, bound to be one with it in stock.

I searched most of today loads of stoes etc but none to be had. Not to worry back to the dremel...

Glen

What about the little Trend router?
http://www.axminster.co.uk/default.asp?part=TRENDT3EK
I think it would serve better than a dremel, but the collet may be a little large?

Not bad, and a good make. How do they do this stuff for this money... And post free...


Glen:)

that's an ideal router, 1/4 collet is what you want as ypu can use a whole range of milling machine catters and it fits all the standard router bits too.

XAIRFLYER,
What software are you going to use?
I don't know if you have seen it but there is some free stuff from Emachine which you download and design your 'whatever' on then send it back to them and they produce the goods! What we need is a cad package as good as theres that then converts it to G code and then controllers the steppers. I would like to think that someone will say 'hay have you not seen this' and point us in the right direction but I doubt it.

Any thoughts

Gus

Gus, there's plenty of cheap stuff around. You can use Ace converter to generate 2d g-code, or if you buy the Mach2 cnc controller, it will import your dxf or jpg files to generate g-code for you. It also includes a toolpath verifyer. Well worth $150US. As for cad, I use turbocad. You can get it cheap on ebay, but I got mine from Australia - http://www.narellansoftware.com/ but it worked out that the shipping was more than the software! There is also a freee version which will do 2d only somewhere on the net.

xairflyer,
hows that table coming on?
I'm stuck in to having to move house (hopefully bigger workshops no neighbours, she in doors wants more bedrooms!)
How about a few more pics.

Gus

HI,Gus
Could do with some more room myself in southend on sea and i have people next door. Hope all goes well with your move.
Just about to start my build soon.

Glen

southend on sea -cool - does that mean Gus is related to the "Prince of Prittlewell?"
http://www.southend.gov.uk/content.asp?content=3112

EDIT: yes sorry, should have said Glen not Gus
this all started cuz I was half asleep and had to google to
comprehend that "southend on sea" was a "place"
I'm gonna go have a nap now....
:confused:

I dont think gus does live in southend but i do. i dont no were he lives..
Glen

A trial version of Mach 2 is available free. It can do something like a thousand lines of gcode, more than enough for most hobby things. I use it and it is absolutely fantastic!
co

Will give Mach 2 a test run, as it were.
I'm based in Yorkshire, Southend isn't that near where 'dads army' was based?
Has to be 'nation's best sitcom', got my vote.
Have been looking at houses all day, very boring but found one with 3 rooms in the celler and a double garage!
That will do for me.

Gus

sounds nice. No dads army filmed in Norfolk about an hour and half from this end.
Germen: YOur name will also go in the book. What is it!
Manering: Dont tell him Pike

I am in the middle of re assembly and setting up after painting, took a long time getting all painted the way I wanted it.

Will post some pics in the next couple of days.

I am going to use TurboCNC for now, also desk engrave for some simple starting to learn stuff.

xairflyer,
hows that table coming?
I'm living in a house full of cardboard box's (the wife is getting ready to move) and my workshop is full of rubbish that she should have thrown out years ago, so I am stuck in front of the pc and cant do anything.
You where finishing off the painting last I heard, is it finished, any pictures.
Keep going mate, you have come to far to leave it like this.
Finish this baby, and with luck you will be making parts for you own flyer!

Best wishes

Gus

Nearly have it back together, I am busy trying to get my new aircraft finished so I am not getting as much time on the cnc as I would like.

I have a couple of parts I want to cut out of lexan for it so I would like to get it running fairly soon.

Below is a pic of how it is coming together to wet the appetite.

xairflyer,
That looks like the 'dogs whatsits' absolutley brilliant.
It really is coming together and looking great, the scateboard bearings are better than I thought they would but I will be using ground steel rods and bearings from RS supplies (because I have them already).
Where do you get your supply of white nylon from?
It really does look great, keep at it!

Gus

I have a mate who works in a toolroom and he gets a bit for me now and then.

Radionics do it but not cheap, I recently bought some round nylon on ebay, nice and cheap.

many thanks for that xairflyer, the wife just asked me 'what does the dogs whatsits' mean and I then thought that I hope you know as well. Incase you don't it means the best thing since sliced bread (the saying is usually used by blue collar workers (like me) on the shop floor).
Anyhow very impressed with what you have done and am looking forward to seeing it start cutting with vengence.

Best wishes

Gus

xairflyer,
whats happening, any more done to your table?
They say moving house is the most stressfull thing you can do and they are right, I am sick of estate agents, seeing houses, and people telling me that subsidence doen't matter but above all I am completely lost without my workshop. I had hoped we would have moved by now, but there are a lot of 'muppets' out there who pull out of chains without warning!
Lets see some more pictures and updates I am going out of my 'shell like' up here!

Best regards


Gus

I'm a bit frustrated at the moment as I can't get working at it.

I am in Taunton somerset at present, finishing off customers aeroplanes.
Back in a couple of days but then have our big trade show a week later and will be flat out getting ready for that !!!:(

Might get a day a couple of evenings next week to connect it up to the PC.

Bu sure to let me know how the Lexan cuts and what feeds you use. I am going to be mass producing parts in Lexan...

xairflyer,
don't drink to much of that 'scrumpy' or you will be sick as a pig for a week, I know my wife has an relative down there. Learn from my mistakes, she still brings it up when we have an arguement!
Being a monk sometimes sounds quite good.

Best regards

Gus

I have been pondering this a while,
IMHO-I'm finding the roll-tap as a bit counter-intuitive when applied to MDF.
If it's purpose is to displace material- that is perfectly logical for
sheet metals in a flanged / flared hole.
To displace MDF suggests breaking the glue-particle bonds.

If it makes an undersized hole then I can understand how the
screw is grabbed in the threads and shank but otherwise I don't get it?.

:confused:

The simple difference is when you tap a hole with a normal tap you remove material to cut the thread, the roll tap takes what it removes from the bottom of first thread and pushes it into the peak of the next, so strengthening the thread form.

Still having trouble applying this to MDF, can't see how it's that plastic? Anyways, whatever its doing in that hole - its make a good thread so I'll shutup.

MDF is really pretty soft under the surface layer, that's probably why it works well.

Hope to have this machine up and running shortly (at last). Unfortunatly I never got it finished before I had to begin work on my new aeroplane which needs to be finished before 10th June due to airworthiness requirements.

So the past three months nothing has been done to my machine bar the odd collection of tracking etc for the cables.

During building the plane I had to make a couple of parts from Lexan which I could have easily done on the CNC and was tempted to spend a week finishing it off, but had to resist and cut the bits out by hand.

Will come back shortly with the progress, just need to set up the rails and wire it all up again. Then the fun begins with the software.

xairflyer, how is that machine of yours coming on?
It has been a while since I was able to visit the thread and you had a plane to finish first, so the CNC had to go on the back buner. Have you got anymore done, all my stuff is in bits in the new garage along with a mountain of boxs that still have to be unpacked for the house. Still got the PC working and have been busy earning money so she who must be obeyed can spend it.
Any photos?
regards
Gus

Hi Gus

Yes finally back working on it. I am setting up the rails at the moment, got all the motors fitted again and Just have to cut out a replaceable cutting table to fit onto the main one.

Next job will be connecting it to the PC - could be fun

Here is my desigh so far. Ihave not added any rails because I don't know what kind I am getting yet.

xairflyer,
My friend with the pcb (draw slide version) router is using a brushless electric motor as a router (they are made for model electric aeroplanes) it is very quiet and very, very powerful. Its called an 'outrigger' because the outside rotates with the prop or in this case a collet. He uses a brushless controller and speed is from nothing to very fast but the cost is ALOT. He was lucky he had one lying around.
Gus

Do you think you can get a picture of the brushless outrunner motor your friend is using? I am interested in the specifications. I have hand wound several motors like this and think it would be cool to make a custom spindle.


Bill

I'm back at my machine again, had a very busy summer with a new aeroplane we are working on and I have found that even though flying (both models and full size) was once my hobby the full size side of things has now taken over my life !

So I have dusted down my CNC Machine (glad I got to the painting stage before I let it go for a while) and have now aquired a PC especially for it so I can get my motors wired up.

There has been probably loads happening since I last viewed the site (Aug) I expect there is some new software, so once I get things connected up I will be asking the questions !!!

Any of you guys who corresponded with me before have there machines working I would love to see how they turned out so let me know.

Seamus

I have decided to order HobbyCNC's board (very well priced, I think it worked out about 80 euro delivered hard to beat that) and keep my single driver boards for manual testing etc.

I am trying to set up my rails and it takes a bit of time to get right, I think I will need to add some supports to prevent flexing especially on the Y axis. Dont know whether to go with a fixed piece of wood or some sort of adjustable screw.

Next stage will be getting the PC to move my steppers !!

why not both. fixed wood to a Point AND THEN a 2-3 peice screw setup to ensure there is no movment at the highest point of movment, being the center of the two rails making up the Y axis on your machine.
I'm thinking if you use two screws you can basicly do the same thing a 4 screw mounting block does. Just matching the two screws to be at the opposite of your bearings on your Y axis. That will remove all up down and foward and backword or twist if you will, flex generated by resistance of the cutting tool. Would also dampin vibrations generated by the cutter bit kicking when it hits something hard to cut.

Cant put anything on the inside of the rails due to the Z axis, The z axis will keep the rails apart ok, just need to prevent widening of the rails and fore and aft movement.

Y axis is the weakest link, when I get it running I will change it to soild bar and use pacific bearings like the z axis.

I dont think you are following what I'm trying to say due to my wording. Ok, here is the deal. you have your Y axis travling on the INSIDE inbetween the two parallel rails. with bearings. Now the problem is the bottem rail can bow down a bit and the top rail can bow up a bit. either or and you get a lot of extra play in the Y axis due to this gap created. So what I'm saying is becuase your only covering one half of the rail using the bearings in a V shap. You should make like a HALF mounting chuck like you have your RAIL's alined with. do a half block looking like a V on the TOP rail and a v on the bottem rail. So all you have to do is tighten the screws till they make contact. Then add even tightening, to make sure its secure. This would be in the middle of the rail, and the Z is the transfer unit of tention. I could draw and post a PICTURE if you would like but its an EASY and sound way of making the Y axis 100% secure and stable.

I understand now what your getting at, I will try it out.

I am having problems with my z axis motor stalling. The motor is new and 127 ozins all I am ding is running the carriage up and down with no router attached.

I think it is my leadscrew (which is 10mm all thread) is tight in the nylon block, I am running it manualy with a driver board single phase mode and not by the PC so I was wondering would it be ok in 2 phase mode which will give it more torque.

Just been reading MVaughn's log and I think I will remove my drive block on my Z axis a make sure it is running freely, and try stick it in the freezer to shrink it before re tapping.

Took apart the Z axis again today, and my 18v cordless drill had a job turning the screw !! So I thought I'd better strip it and free it up.

The drive screw is 12mm x 1.75 pitch all thread not 10mm as previously posted, approx equivelent to 14 teeth per inch.

Made the tap from a piece of the all thread originally so I decide to run a proper 12mm tap down it. Done that then ran my homemade tap in it a few times and all was well.

Fitted a IGUS flange bearing to the turned down end of the drive screw and All nice and free now.

you may want to think about gearing, that motor is plenty strong enuff to lift your Z, HECK thats 20x more powerfull then the motor on my Z BUT I have my setup geared. 50/1 ratio aprox. Sure I loose some speed but at least I have 10lbs of lift with a 2" wide x1" tall motor 7.5* stepper. An other question I have is what are you running again for power to your stepper motor? remember you can run upto aprox 15-20x the ratted voltage on the motor so long as your using a chopper driver to keep the current in check. For your setup I'd reccomend at least 30v provided your motors are ratted for at least 2volts. voltage + proper current = fast powerful motor.
Also the 2 phase suggestion you had mentioned. If your motor is a 4,6, or 8 wire mtoor you can set it up as a bipolar 2 phase motor which will give just shy of 2x the tork. Highly reccomended provided your coil resistance is below 30ohms.

Also how did that mod that I had suggested to you work out for you, on removing the flex in the Y axis?

I am just working on the Y axis again today, I have actually drilled into the middle of the bottom rail and fixed it to the gantry, so now there is no flex. I have it set to the X axis and now I am going to set the top rail to that.

Obviously I can't do the same to the top rail as I will have no adjustment, so I will use roughly what you suggested, only snag is I will have to make the adjusting blocks probably from alum, as there won't be sufficent clearance to allow much 'meat' between the tapped hole for the adjusting bolt and the edge if you know what I mean.

Got the Y axis rails set to the X axis so everything is nice and square and perpendicular. Took me a while to figure out how to do it so I have done this out for my own benifit as well for reference in case I forget it again !!

Clamped a piece of aluminum channel (nice and streight) to the top of my table and set it square to the X axis rails/table edge.

All ready had the bottom Y axis rail level to the top of the table, so I then positioned my square (looks old - it is, but accurate) between the aluminium channel and the Bottom Y axis rail.
Brought the table forward so the square was just touching the rail then moved it across to the other side and set it the same.

Once I had the bottom rail set I, roughly set the top rail, then re fitted the Z axis in place.

I then used the square again to set the top rail flush with the bottom one on both sides and checked in the middle.

Spacing between the rails is set by the Z axis, once I felt it was right and all the bearings were turning on the full travel, I checked the measurements in between with a large vernier, and adjusted the rails to get them to match.
This process went back and forth until it was right.

Only thing left to do is finish the half chuck for the top rail to prevent any flexing.

Added a support to the top rail of my Y axis as suggested by Berin.

Not much room as the Z axis comes very close, so I had to use a grub screw for the outer one (hard to see in picture) so there was sufficent clearance.

Mainly wanted it to prevent any upward or forward flexing and it seems to have stopped that. Will make a new one once I have the machine running, as I have a few extra holes in this one !

Everything is setup now so I am ready to connect to the PC.

I think I will play about with a few spare motors on the bench first to I see how everything works, I have as yet not really looked at any software or how to use it. I bought turbocnc so will try it out first.

Anyone got a file I can use to get me going, something simple just so I can get all the motors moving in a simple cut.

Just found this thread guys, great stuff. Keep the UK links coming as I havn't started building mine as the prices for motor's etc here are high compared to the US. But this thread has got me going again.

If you have a plan that can be built without milling machine's etc any chance of a copy/ link

Steve

xairflyer, just set up Turbocnc and use the jog buttons, or simple G00 moves . That will be plenty to get the motors moving.

There is a set of plans available to down load on this site.

http://cnczone.com/modules.php?name=Downloads&file=viewfile&id=4

Thanks Kong, going out to the workshop NOW to connect things up

Just found this thread guys, great stuff. Keep the UK links coming as I havn't started building mine as the prices for motor's etc here are high compared to the US. But this thread has got me going again.

If you have a plan that can be built without milling machine's etc any chance of a copy/ link

Steve


If you're looking for steppers in the UK, this site may be worth a look.

http://www.distel.co.uk/asps/all.asp?TR=53

Regards Terry.....

Thanks guys

Had a look at the distel site, would these be ok for a cnc machine to cut balsa/ ply etc.: 5.1V @ 1.3A 4PH 110-OZ 200 STEPPER MOTOR

Steve

Xairflyer, so tell me how did the that fix I had suggested work out? you made it exactly how I was thinking. I would reccomend you considering adding maybe 4 more to have 6 of those half arches between the top and bottem rails to mop up any more play that may rear its uggly head SHOULD you find that that is the case. But in any case if your looking for some good example files. there are a lot of them on the net or look me up and I can set you up with some good files to play with.

berin1 at hotmail dot com
I've made guinness logo, i've made a logo for the local chines food resturant (my best firends parents own it), I'm working on making stuff for a local bar ect.......
Also if your looking for ways to ensure squreness there are some tricks you can do. For example take some kind of wood pine maybe? and cut exactly equal in demention peices 4 of them. or just get precut stuff and make some squars out of them. Then put one squar in each farthest corner and clamp it down. Then put some kind of a routing bit on your rotory tool. next make a half depth cut into the wood at each corner. either dive or router in via a side. Do this for each of the 4 corners. Next un clamp them and mesure the depth from the bottem to the wood to the bottem of the cut. If its off then you know that side is to high or low.

Thanks guys

Had a look at the distel site, would these be ok for a cnc machine to cut balsa/ ply etc.: 5.1V @ 1.3A 4PH 110-OZ 200 STEPPER MOTOR

Steve


Those are the exact ones I bought. Been cutting MDF and some aluminium with my machine. I'm driving mine with Alans PICStep drivers at the minute (Bipolar half winding).

Regards Terry
www.terry-is.f2s.com

Those are the exact ones I bought. Been cutting MDF and some aluminium with my machine. I'm driving mine with Alans PICStep drivers at the minute (Bipolar half winding).

Regards Terry
www.terry-is.f2s.com

Thanks Terry, looks like I've started collecting parts :cheers:

Steve

Xairflyer, so tell me how did the that fix I had suggested work out? you made it exactly how I was thinking. I would reccomend you considering adding maybe 4 more to have 6 of those half arches between the top and bottem rails to mop up any more play that may rear its uggly head SHOULD you find that that is the case.


Yes Berin they are working out fine. I will make up new ones probably form ally when I get things working.

Connected my hobbyCNC board to three spare steppers on the bench and eventually found out how to jog them about after I set things up in the configuration.

Had to do this twice as I lost it all once I came out of TCNC did'nt realise you had to save the file and then reload it every time you open the program.

I know nothing about G codes but eventually got the motors to run on there own with a sample file in the program.

Can't figure out how to jog to a position and start from there as any sample files I have returned it to the beginning again !!

When I press F8 and go into the Jog screen, I can get a axis to go to a point, but it won't let me zero it at that point ? going to have a look on the turbocnc forums to see what I can find out.

Connected up to my machine tonight and finally got a gcode program to work that I could understand.
Figured out how to setup deskengrave and typed the word JOE, after a few attempts got the sizes right and cutting (drawing) speeds.

Going to put together a step by step "how to get going" file and post it on here, as I spent a lot of time myself the past couple of nights on what some would consider basic stuff, but not that simple when you have not done it before.

Stuck a pencil in the collet of my router and left the Z axis motor on the bench (did'nt want to break my pencil :-)

So below is a picture of the first thing my machine actually done on its own.
It works !!!

Might get brave tomorrow eve and wire up the Z axis and try a cut (after I make the actual cutting table) - first cut will have to be JOE again as that is all I can figure out at the moment !

Excelent, that will help others also.

when I get home I'll a good file for ya, but I'll worn ya early, this will require a FINE tip! either one that comes to a fine point? or just a fine ball tip. (in other words 1/8th dremel bits). I'll also scale the thing I'll send you up a bit. I'll also take it one step firther hee..hee..hee..! the file I'll send you I'll code it so it requires a cutter bit at the end of the processes and will cut the thing out. So you'll have to raise the work peice or set it on top of an other bock of level wood so as to not cut into your cnc working tray.


P.S. THIS ALSO MEANS YOUR FIRST TOOL SWAP, I'll explain IN the file live how to set the right depth on the fly using turbocnc. Becuase there is a PAUSE function which which works great. because I can also add comments into the gcode file which you can read on the fly ;).

when I get home I'll a good file for ya..........

Is this something you will be willing to share? I'm sure it would be helpful to all of us! :banana:

I've made guinness logo, i've made a logo for the local chines food resturant (my best firends parents own it), I'm working on making stuff for a local bar ect.......
.
Mmmmm...Guinness...along with Bushmills, the necter of the gods.

Looking good Xairflyer! Glad to have you back, and working on your machine again!

Not fair I will have to wait until tomorrow due to the time difference !

I gues I could share the file with the world but i wont be home till late tonight fri. due to the fact that I have to go hang out with my parents tonight :p .... Oh well got to be the good son. xairflyer will prob give an explosion of delight on this post after he runs the file I emailed him.
by the way I'm in the USA/eastern time zone

I have some sort of snag with my measurements in turbocnc, 600 on the screen for the X axis is only 300 on the machine, also the Y is also half what the screen says (I am using mm).

I have some sort of snag with my measurements in turbocnc, 600 on the screen for the X axis is only 300 on the machine, also the Y is also half what the screen says (I am using mm).

Cut your step size in half. Under scale in the motion parameters.

Cut your step size in half. Under scale in the motion parameters.

Is this what is wrong or is it just a fix ?

Xairflyer, if you have microstepping on your drives, this could be the cause of the mis-calculation.

its only a miss calculation easy fix, I belive you have your setup straight connected no gearing, ok simple to do the math.
say your rod is 20 turns per inch, and your stepping motors are 100 steps per rotation on whole stepping. (tpr=turns per rotation/tpi=turns per inch) 100tprx20tpi=2000 steps per inch. ok now to turn that into a dec. which is what turbo runs on 1"/2000step 1 inch devided by your total steps per inch. yields .005 or five thousands per inch per step . Ok so if your half seping that would be .00025 25 thousands per inch per step.
Just remember the number of steps your motor takes per rotation * the number of turns the screw, lead screw what ever takes per inch is your total steps per inch. Then devide 1 inch which is what your mesuring by that large number to get your decemal. Thats on a direct drive though which you have. If you are using a geared system like I am there are just more numbers involved. And that is nothing more then counting the number of teeth to do a ratio.
so to cap off if your half stepping a 100 step per rotation motor then your going to end up with 200 steps, or 1/4 stepping you'll end up with 400 steps per rotation etc......

Is this what is wrong or is it just a fix ?

Both :)

Tell us your lead screw tpi, and what microstep setting your HobbyCNC board is set at.

OK, I see in one of your posts that your screws are 1.75mm pitch. Under the motion parameters, highlight the scale line and hit "C" for calc.
Enter 200 for steps / rev, 1.75 for Pitch, NUmber of microsteps (8 if set to 1/8), and leave gear ratio at 1:1. You should see .00109375 for your settting.

xairflyer have you run the file? and what do ya think? To the rest of ya who wanted that file of mine here it is.

let me know what ya think!!!!!!!!!!!!!

Brilliant! :) I can't run it yet, but would like to in a week or two, give or take a month or two. ;)

Nice job so far, Xairflyer. Interesting thread.

ger21, the settings in the controller make little difference. Its the controlling software which must know what the controller is doing PEIROD! Also pitches and all that also make little difference in the equastion. The only thing that matters is the number of turns of the leadscrew per inch, and the number of steps it takes to turn lead screw one turn. Then you * those numbers togeather and you have the numbers you need to know period for any controlling software. 1" is an easy unversal mesurment.
So if its a straight shaft driven or geared via gears or belts etc..... doesnt matter there are the only two numbers you need to know period! Number of steps by the stepping motor to turn the lead screw once and the number of turns of the lead screw to move one inch.
Just for an example if your motor is on a geared setup with a 50/1 gear ratio, and your lead screw is a 20tpi. and the motor is a 48step motor 1/4 stepping just to make it tricky ;). Remember if half or micro stepping multiply the denominator by the base number of whole steps of a stepping motor. So half stepping is 2xspr motor 1/4 stepping is 4xspr, same with 1/8-1/16 etc....(steps per rotation). Because its the number of times your increaseing the RES.-resolution of turns per rotation from the base whole stepping number of steps capable of the stepping motor.
well 4x48step=192 steps per turn, ok now 50/1 gear ratio 50 turns * 192 steps= 9600 spr OF the lead screw. So now if we know it takes 9600 steps of the motor to turn the lead screw once, and it takes 20 turns of the lead screw to equal 1".
20 leadscrew tpi*9600steper motor-spr of lead screw=192000. Now to make a decemal which turbocnc runs on to tell how many steps it takes to move X distance. X being 1" in the equasion that we are using. 1" / 192000spi=.000005208 520 hundred thousands per step per inch.
Any question's class? turbocnc runs on decemal, kcam runs on spi, so does mach1 I believe.

The information I gave was entirely correct.

1" is an easy unversal mesurment.
Unless your using metric screws and cutting in mm.

The settings in TurboCNC make all the difference. I explained what he needed to enter in TurboCNC to make it work correctly. TurboCNC will do all the math for you.

I see your talking about his microstep setting. again, you can enter this in TurboCNC.

Also, he's using metric screws and mm, not inches. Metric screws are specified by pitch, NOT turns per inch. Again, TurboCNC has a place to enter this info. I explained the easy way to do it. With the 1.75mm pitch screw, and 1/8 microstepping, you need 8*200 steps per revolution, or 1600 steps to move 1.75mm. 1.75/1600 = .00109375 mm per step, which is what I also gave in the example above.

The method you describe above works fine for inch units.

The difference between TurboCNC and Mach2, is that in TurboCNC, you specify units/step, and in Mach2, you specify steps/unit.

xairflyer have you run the file? and what do ya think? To the rest of ya who wanted that file of mine here it is.

let me know what ya think!!!!!!!!!!!!!

Berin, what did you create that with. It look like a raster to vector conversion. It looks like if it was cleaned up the file would be a fraction of the size it is now.

No Berin I hav'nt ran it yet as I need to make sure my machine is actually setup properly first.

I think I know the problem now as I forgot about the half step which I have the hobbycnc board set at.
I have entered 200 for the steps instead of 400.

Why would you want 1/8 or 1/16 step would the movement not be extremly small ?

I am going to have a look at the setup now tonight and if OK I will try to run the file tomorrow.

The reason to use 1/8 step is that the motors should run a lot smoother. That's the main purpose for microstrepping.

oh i'm sarry didnt catch the metric part first time. As to the file, no that was done free hand TOOK FOR EVER!!!! I have all of the micro jaged movments because when blown up to a certin size and routed it looks rather nice routed in clear plexy. Though that was my final beta not my final final. My true file peice is flipped over backwords so as to see the file from the back side of plexy. But the file was designed to be cut with a needle point milling bit. The file was created using dolphin cad.

and yes as ger21 said the micro stepping smooths out the motion of the motors. I'm sure in your bit of playing you've found that the entire machine vibrates considerably as the motors turn. The thing of it is is that the only time you get vibration is when your are at total magnetic stop point of one coil. if you run half step and run the machine slow, on every HALF step there isnt an impact sound of the magnet and shaft locking. Where as on the whole step which is the true stopping point there is an impact sound. The vibration can cause problems espcialy in find detail. And the smaller the micro step the higher the resolution is.

and yes as ger21 said the micro stepping smooths out the motion of the motors. I'm sure in your bit of playing you've found that the entire machine vibrates considerably as the motors turn. The thing of it is is that the only time you get vibration is when your are at total magnetic stop point of one coil. if you run half step and run the machine slow, on every HALF step there isnt an impact sound of the magnet and shaft locking. Where as on the whole step which is the true stopping point there is an impact sound. The vibration can cause problems espcialy in find detail. And the smaller the micro step the higher the resolution is.

But also the slower the machines goes, right? Just asking to satisfy my own curiosity...

But also the slower the machines goes, right? Just asking to satisfy my own curiosity...

No. If your using 1/8 step microstepping, for example, the computer just sends 8 steps in the same amount of time it would normally send 1 step if using full steps.

The exception, which usually only applies to servos with higher encoder counts, is if your computer can't send steps fast enough, than your speed may be limited. Mach2 can output 45,000 steps/ second. DeskCNC 125,000. And Gecko announced that in a few months, they'll be releasing a pulse generator, which Mach2 will support, which can output I *think* 400,000 steps per second.

In the instructions with the HobbyCNC board they mention that using 1/8 or 1/16th step require's a lot of computing power. Are they referring to the software or the actual pc hardware processor, memory etc.

The only thing it requires is a faster pulse rate from your computer. With TurboCNC, faster computers CAN output faster pulse rates, up to a certain point. I really doubt you'd have a problem.

if you have less then a 486-25mhz using turbocnc and less then 16megs of memory NO WORRIE MY FRIEND NO WIRRIES!
Javadog the speed of the machines doesnt matter period, the only thing that matters is the material your working on. Because if its a precision machine think about it why would it be less accurate if the machine moves faster? (aside from flexing of the machine) unless your loosing steps the machine will always do correct movements. You just have to watch out for the way the material your cutting cuts. So say if you where routing metal like aluminum, you can only cut it so fast depending on the bit you have. If you have a cooling system you can cut faster but if you cut to fast you can also gum up the bit. Now if you are drawing plotter style using a machine, you really have no problems with speed. Heck the faster you go the sooner you finish :)

Looks great,

Have read through all of this thread with great interest!! Great looking machine and will hopefully be really solid and rigid. I would definatley pay to get hold of the plans for this... Please let me know if your interested in selling your plans !!!!!

Keep up the good work :banana:

I am using 2 vexta 266 2A motors and 1 shianano Kenshi 2.4A motor and my 400W computor PSU is having none of it.
Although it is rated to 15A it is switching off when I try to run all three motors.
Total draw is 12.8A so it is pushing it, so I decide to search through my other steppers and find the one with the highest torque with less amps than the one on my X Axis table which is 2.4A for now anyway until I build a 24v PSU.

All my my motors apart from the Vexta 266's are second hand and I have not been able to get any specs on them.

So I have decided to test them myself.

I connected up each stepper in turn to one of my 6A single driver boards and made sure I had the resistors correct on each motor to match their ratings.
The motors were stopped so I could test a holding torque. :idea:

I then made up a lever from a piece of aluminium strip which I bolted to the stepper, and marked off segments for where I would apply a torque load.
I went with this method as I could grip the shaft in the vice, as It was easier than making up something that would'nt slip if I applied the torque load direct to the shaft and gripped the stepper in the vice.

As I really only wanted to do a comparison it would work just fine and the actual torque of the motor was not needed to be found, just the best one.

The amount of load applied depends on the length of your lever, I found that a little force gauge I had that went up to 350grms worked fine at 10-25cm depending on the motor. Just push or pull the lever at a measured spot until the motor slips.

As an example of some I tested my 2.4A 2.88v motor was 320g @ 20cm which equals 6400gf cm or approx 89 ozf ins

Another motor 1.2A 8v was 340g @ 25cm =8500gf cm or 118ozf ins
this was my best torque motor at the 12.3v of the PSU but being 8v was also the slowest.

I assume the lower voltage motors eg 3v turn faster at say 24v than a motor rated at 8v or is speed down to the motor itself ?

anyway for next time I will make a torque loading lever for the stepper shaft just to get better readings, but as I say for comparisons above works.
:cool:

if your PSU is cutting out the problem is more along the lines of the amount of resistance, and rate of draw.
put it this way, most COMPUTER PSU'S will trip if the resistance in the load is below 2-4ohms.
Also you mentioned that your 8v motor was very slow, something you should check on is the COIL resistanc of the motor. The rattings on the motors are the tolarences not the SET rattings. Stepping motors which have an ohms resistance between .5-10/15 ohms are always very fast and powerful, but the higher the resistance the more voltage the motor will require just to overcome its own resistance. If you want to try a test get a few 1-5ohms 10-20 watt dropping resisters (you know the kind that have a ceramic shell around them and are white and often squar-ish). And put each one in line between the motor driver and the computer PSU. you should find that the psu wont kick out on you any more. To be honist if you want a better setup, pick up 3 transfomers which output between 12-30v 2amps+. An other option which I took was to use multi laptop psu's which each output between 12-24v 2-4amps. works very nice and there is no sharing bandwith of the current problems :). Just have to watch out for the load requirments. happy cnc-ing