Hello, I am building a router to cut foam sheets, lite plywood (up to 1/4") and balsa wood with the occasional light gage aluminum cuts. my problem is that I have an x axis of about 5 feet, and from a little research on the zone here I think a belt drive system would be better and more cosst effective for my router. i have picked out what slides I would like to use from vxb.com. the router will have a moving gantry and be constructed out of aluminum tube, 2X2X1/8". the y axis will be just over 2 feet and a z axis of about 6". the frame is being built right now and I have 2 steppers that are 117 oz in tourqe. I plan on getting the 3 axis board from hobbycnc.com. ok, so what I would like to know is how well does this system work, what parts do I need, and will the steppers I have work, or do I need a bigger one for any of my axis? the belt system I like the best so far is the open loop system with the stepper mounted to the underside of the gantry and clamped at each end of the router. I estimate the weight of the gantry to be around 50lbs max. Once I get the frame finished welding I can post some pics, but anyone got some help with the info given?

I would think 117oz/in steppers are going to have difficulty in moving a 50lb gantry; I would probably go wth the 305oz/in hobbycnc motors. That's what I'm using on my belt-driven machine.

Another thing to consider, is that your steppers will need to be geared down in order to drive the pulley. The gearing will depend upon the type of belts you are using (how many cogs per inch). Your resolution will be very coarse if you don't gear down. This ads complexity to the drive mechanism that is wise to engineer before you begin construction IMHO.

Check out David Steele's design at www.solsylva.com. A modification of his machine is what I am building.

nice link, lots of ideas. I have attached the ACad file for the router to help out. the router is a modified version of twistedfuse's router. I figures I was going to need a bigger stepper for the x axis. will the 117 oz steppers work for my y and z axis? I plan to have acme screws on them. the speed of the router is not as critical to me (i'd like to be in the 250-200 ipm)range and the precision needs to be about .006 over 4 feet. I don't know if I am wording this all right as I am still learning, but I hope that helps. I will be cutting RC airplane parts out for the most part from balsa and up to 9mm depron for the foamies with the occasional odd-ball stuff.

(i'd like to be in the 250-200 ipm)range and the precision needs to be about .006 over 4 feet.


You might be able to get that with a HobbyCNC board, 300 oz steppers and 1/2-10 5 start. Maybe. Those 117 oz motors won't get you 100 ipm.

I had a feeling that those steppers wouldnt work to well after lurking around on here. so i guess i'll ditch the 117's and just get the whole kit from hobby cnc. I will use the acme screws on the y and z axis but i wanted to use a belt system for the x axis, which is where I am stuck at. I saw a pic on here yesterday that looked exactly like what I had in mind and now I cant find it. i'll keep looking and post it when I find it.

Sorry, forgot about the belt drive thing. With belt drive, it can actually have more speed than with acme, but with less torque. All depends on how you gear it.

I still can't seem to find the sketch I saw but it was a direct drive off of the stepper with 2 rollers (one on each side of the stepper) that made the belt run in a U shaped path. it looked fairly easy to make up and work with. dang I wish I could find that sketch!! I should have my frame home this week and get the full visualisation of the build. if anyone is intrested I can post some pics. this will be a slow build bacause of the whole cash issue.

ok, here is my own little rendition of what I can remember, I know there has to be a tensioner somewhere in the belt system, but any thoughts on how this will work??

I spent a lot of time looking at the details of a belt drive system, similar in concept to what you have drawn. The basic conept is simple, but there are a lot of details of the belt and pulleys which can have a huge impact - such as backlash from tooth gaps, etc.

After adding up all of the parts needed, including fairly precise timing pulleys, etc, I am strongly THINKING that it is better and cheaper to use rack and pinion ( looking at boston gear, but there are others as well). My INTENTION is to use direct driven pinions from fairly beefy 1/16 th micro stepped motors.

Something like 20 - 25 tooth gears with 20 tpi rack and 14.5 degree pressure angle. (lots of more informated opinions in this area than mine)

In theory, this will provide something approaching 0.001 inch micro steps, and is similar to the mechmate concept. Backlash is a bit less clear frankly, so I am still trying to figure this out.

Bottom line, is that to get good (design) precision with belts, required really good belts and timing gears. Getting timing belts even close to rack size tpi is not feasible. It appears that rack and pinion is just really reasonable to produce especially if you are willing to accept some industry standard high volume part concepts.

Hmm, I looked at the rack and pinion idea, but thought belt drive would be easier. Hey I am open to all options here, I just need to keep the cost down (thats why I am trying to get away from the ball screws) all good points keep em coming I will most likely not be able to afford any of the screws/belts/racks or whatever for a while. I just want to purchase the parts once and not twice. :)

From what I am seeing, the best way to keep costs down and obtain reasonable precision, is to focus your spending on as few of components as possible.

An example - the rack and pinion option. There are a number of assocated parts that go into a drive like this
- Rack (s)
- Pinion (s)
- reduction gearing
- stepper motor
- stepper motor driver
- one motor on each side, or a mechanical linkage
- Mounting the pinion on the stepper motor

Each part adds either to the precision, or frankly, non precision of the total system, so just like a chain, the most out of precision part, or installation of a part, can really harm the end result.

For my own project, I have NO fancy tools to build up the system, and I have poor craftsmanship, so it has to be constructed as simply as possible or it simply will not work.

First items on the list - get rid of gear reduction - nothing good can come from building this up myself - so I am going down the path of hefty stepper motors with lots of low end torque, direct driving a modest size pinion gear. This is done routinely by the mechmate projects.

Rack is actually quite cheap - esp if you stay with the one I pointed out.

Second item on my list - driver circuit - I don't have $ 100 / each for 6 stepper drivers (2 per axis) - so I am using linistepper drivers. They aren't perfect, but for $ 35 / each, it is ok. Even with only 1.5 amps, you can get some amazing torque from a nema 34 motor. That brings up another point - sometimes, a nema 34 motor is CHEAPER that a nema 23 motor for the same torque due to the cost of high end small magnets.

Third item - drive from center, or both sides - I have decided to drive from each side - this is my splurge area, but it gives me more confidence that the motion will be under control. I thought about a mechanical link between sides, but once again - lots of room for mistakes / imperfect components.

Linear rails - I am still deciding on this area, but it won't be a fancy linear truck concept - budget drive decision.

HARRYN, you got a web-site for that boston place??

HARRYN, you got a web-site for that boston place??

Sometimes, life is simple. :)

Boston Gear = www.bostongear.com

Let me know what you are thinking for linear rails. I am still stuck on UHMWPE slides (diy) vs pacific bearings redi rails 65mm size vs Frelon type bearings (also pacific bearing) vs ?. I am not a big ebay fan, so I am trying to avoid that, perhaps to my detriment.

As for rack and pinion, etc., may want to give these guys a try:

Superior Bearing Company
www.SuperiorBearing.com
937-470-9524

Excellent service and prices. A lot of people building a mechmate cnc router(mechmate.com) are buying from Superior Bearing Co.

Cheers,
Bernhard

Well after some more surfing on the web, I found that the r&p method will be a lot cheaper and sounds just as precise. as a note I was re-reading my posts and where I stated I need .006 precision over 4ft well that actually should be like .03125 or 1/32". oops. so here is an idea i'd like to run by you guys. If I get a nema 34 stepper (how big do I need to be looking at) and mount it to the underside of my gantry and mount the rack to the lower portion of the frame, will that work well? I found a local supplier for boston gear, so I am leaning towards them with the rack (20 diametral pitch, 14 1/2degree press. angle, made of steel) and for the pinion (20 diametral pitch 14 1/2 degree press. angle, made of steel) so now I have some probally stupid questions. since I am going with a nema 34 for the x axis, do I have to use them on the y and z? once all built how will I be able to callibrate this thing so that everything on the 3 axis jive speeds, steps per inch? and finally, will the hobby cnc board still work with the larger nema 34 motor? sorry for the long post and stupid questions, thats why I am a newbie!! thanks!!

Hi, glad to see progress - at least on your build - maybe someday on mine.

As far as the question on motor size - this really does not matter as far as axis to axis, but in my case, since I am using 2 motors on the X and Y, I am planning to use the identical motor on each location. Since this already makes most of the motors the same, then I am strongly leaning toward using the same motor for the other axis as well, even if it is excessive, just to keep life simple for wiring, mounting, etc. This is not a requirement.

As far as the driver boards plus motor matching, this requires a bit of an exercise in learning about steppers - which I think I just barely understand well enough to point you to the electronics / stepper motor section for real advice. If you post your idea for starting points for motors and driver boards, you will get plenty of feedback there.

Just to keep life simple, I am planning to use the same rack specs and pinion size (tooth count) for all of my locations. That way, even if my settings in mach are wrong, a circle should still be a circle, just the wrong size, which seems easier than if I have to program each setting separately. - I am a beginner too. :) I am thinking about something like 20 - 25 tooth pinions.

There are a number of build threads where people used rack and pinion- some very good ideas there. Takes a bit of reading, but a lot of good insight.

Also, can you tell us about the botston gear distributor and pricing ? Sometimes, this info is not so easy to come by without asking for individual quotes, which can be a pain.

bml6116 - Thanks for that vendor link. Edit - that is all far east import stuff isn't it ?

I don't think it's possibble for you to get positioning accuracy of .006" over 4 feet, even with ball screws.

As far as motors, buy once, and buy right. I would suggest nema34's with 500 to 1000 ozin. You can be sure that this will not be a point of failure/weakness with your new machine.

Paul

fatal exception, thanks for the input, do you know who would sell a nema 34 stepper in a 5,6,or 8 wire arrangment? i didn't have much time today to search but all I found was 4 wire steppers?? I want to use the hobby cnc board,mach 2, and mastercam for my setup. I also made an error in my post regarding .006 over 4 feet accuracy, I actually meant .03125 or 1/32". oops. I got the frame home today and hope to post some pics here by the end of the evening.

....
bml6116 - Thanks for that vendor link. Edit - that is all far east import stuff isn't it ?

Not sure where Superior Bearings sources their wares. But if you take a look at the mechmate site, that company receives high marks for quality, price and service. And I am a satisfied cusomer, too.

Cheers,
Bernhard

ok here are some pics of the router frame after I got it home today. now I can research the crap out of anything and everything cause it's gonna be a while till I can get anymore parts, but hey, I am on my way!!

looks great so far, even on the iPod touch!

I would think 300 to 500 ozin would be enough. Try keiling, he might have a cheap solution... He has a forum here.

The basic conept is simple, but there are a lot of details of the belt and pulleys which can have a huge impact - such as backlash from tooth gaps, etc.

Only if you don't use the correct belt and pulley ... any supplier will guide you

I am strongly THINKING that it is better and cheaper to use rack and pinion ( looking at boston gear, but there are others as well).

Define better ... irrespective I have found belt both cheap and easy to build


One of the major reasons I went away from rack and pinion is that the cutting head torque for the X plane is only as strong as the pinion spring.

So, if you are building for plasma where there is zero torque at the cutting head, then R&P should be fine.

Alternatively, if you want to mill material such as aluminium, you may find the pinion spring is limiting your cutting ability.

Belts are pretty tough given the metal strands embedded within them.

Andy

andy, could you provide an adequate setup for my x axis? (meaning manufacturer, and sizes/part numbers) as I said I am not set on anything as far as the drives go except that I will use a hobby cnc kit, and at least the linear slides from vxb for the x axis.

Hi

I should be able to help you with that pretty comprehensively.

My machine is manufactured but not yet running. I bought a camera a couple of weeks ago and am creating a portfolio of sub parts which will soon be going up to my log.

I've still got the receipts for the belt and pulleys and will drag out the info.

Make sure though that you don't treat this as prescriptive as you will still need to affirm with local suppliers, etc.

I should have something for you in a few days.

Andy

Hi Andy, thank you for your post. I am not saying that belt cannot work, but from what I am seeing, there are a number of people that only look at the strength / deflection / stretching of the belt, and don't look very closely at what is going on at the tooth interface of the belt and timing gear.

If you look at my build thread, which is more of less still my efforts to understand how much each approach will cost, you can see that just going from "standard gap teeth" to "zero gap teeth" on the timing gear can easily double the price and lead time, esp. if you cannot machine items yourself.

I am not sure if I posted there all of the info I received back from Brecoflex, but I was fast approaching using AT 10 steel wire embedded belt, 50mm wide (almost 2 inches) with zero gap timing gears to obtain similar mechanical tooth strength sufficient to really kill backlash.

I do agree that it does require considerable pressure to keep the pinion driven into the rack, and a split pinion would be better than the single pinions commonly used. This of course is a pain since it is not quite so easy / cheap to obtain rack wider than 3/8 inch in 20 tpi.

Last but not least, I am basing my thinking on a commercial router spec (maybe it was mechmate ?) that called out a restraining force of 80 lbs in every direction on the router at all times. This is entirely feasible, but not a trivial number to achieve without real planning. This is not going to happen without substantial belts. I admit that I have no idea if the holding force spec is a valid one or not, but 10 lbs certainly is not enough to hold my Bosch manually.

I don't see any mention of Acme screws. Have you dismissed this option?
They are relatively inexpensive and easy to implement. Look at Mcmaster for 1/2" precision Acme screws and dumpstercnc.com for AB nuts and couplers. You can direct drive them from the motor shaft. With 1/2" 8 2-start screws you can get 200+ ipm rapids with a hobbyCNC kit and 305 motors. With the 1/2" 10 5-start that can go up to about 350 ipm depending on the weight of your gantry. If you use 2 motors for the X you will have plenty of power. You can see examples of both on the Joes2006 (1/2" 8 2-start) and Joes 4x4 hybrid (1/2" 10 5-start and 2 motors for X). Precision is .009" per foot over a 6" screw (Mcmaster). Acme screws may not be as precise or efficient as ball screws, but they still do a good job. Screws have great repeatability. The precision may be only .009", but you are off the same amount each time you pass location X.

Hi

There are quite a few threads on this forum around belt and backlash parameters.

Its been a couple of years since I read them all but recall that the profile is the important criteria. Some profiles have high backlash (eg constant direction profiles).

Without being able now to justify the purchases I made (erased memory), my receipts show that I purchased T5 profile belts and pulleys.

I ended up with 3 to 1 reduction driven by stepper. I wanted 5 to 1 but the pulleys didn't allow for it.

I might put in a further 2 to 1 reduction at some stage.

The pulleys are 20-T5-16 (tooth-profile-width)and 60-T5-16.

I used roller bearings as pinions.

Not being an engineer, I can't justify belts vs RnP but can confirm the cheapness and ease of build of belts.

For the X axis, I have used 3 * 20-T5-16 and 1 * 60-T5-16. The smaller pulleys cost me A$22.30 each and the bigger A$46.20.

I haven't got the receipt for the belt but I'm pretty sure it worked out to about A$8 per foot. (For my X axis, that is 4 foot each side and 4foot for the Y.

Pictures to follow.

Andy

You can see my x belt setup in the attached pic. I used XL series pulleys with 3/8" belts. The belts are dirt cheap, but the pulleys were about $25 a piece. I used the same on all axis'. They are very easy to bore to the shaft size you need. I kept a 1:1 ratio, but I'm using 900ozin servos, so power is not a problem.

The spindle pulley setup is totally different. H sized pulleys and 1" belt. That's a different story...

Paul

wow, that dumpster cnc place has ALOT more reasonable prices than what I have seen before!! factoring that all in, using acme screws and dumpster cnc parts, puts the acme screws in about the same (a little more) cost than the r&b and belt drive. fatal exception, Nice setup, definaltly heavy duty. what size screws are you using? I was afraid of getting "whip" with having a long x axis and that was the reason I hadn't mentioned it. I also didn't think it would be cost effective for me cause the little research I did estemated that I would have $1k in just the x axis slides and screw setup. now I am seeing that I could have the vxb slides and either belt,r&p,or acme screws for about half of that. I was looking at my router and screws would be a simple setup on all 3 axis. so, 3 questions; what size acme screw do I need (diameter ansd tpi) so that I don't have to worry about "whip"? my gantry weight 26 lbs right now, can I still use the 305 steppers direct drive?(remember I wont be cutting metal very often and at max it would be 1/8" aluminum) and finally, can someone please explain what single start,2-start and so on means for a screw setup, what do I need?? thanks a bunch for all the input!

oh yeah I will be using a dremel for a spindle, not a big heavy setup like most use.

???

I'm using 5/8" screws with .2 pitch. They are OK for my setup, but I would go bigger next time. If your driving is a dremel, they would be overkill, depending on the span.

Put a pillow block on the end of each screw to prevent whip. It's not expensive.

300 ozin will probably be ok if you are using linear slides and ball screws. It all depends on the friction of your system, which is not something anyone but you can determine. If that's what you already have, try them. If they don't work, sell them and buy bigger ones, not nessesarily in that order... Almost gauranteed that you will be able to make the parts move, but you will find out if they are strong enough when you try to get them to move fast...

Paul

Multiple start screws have multiple threads wrapping around the screw. A single start 10 thread per inch screw turns 10 times to move 1 inch. A 2 start 10 thread per inch screw only turns 5 times to move 1 inch. This is because the 10 threads are actually 2 separate 5 thread per inch threads. Multiple start screws are more efficient than single start, and the higher the lead, the more efficient they are.

For such a lightweight machine, I'd look at 1/2-10 5 start acme, which will give you 2 turns per inch. The problem, though, is that you'll need a 6'+ screw (according to your drawing). There's a very good chance you'll get some whipping, but the 5 starts will minimize help to reduce it because it will be spinning slower. It should be good for at least 100ipm at that length, provided it is well supported at both ends. If you go with a bigger screw (3/4"), your acceleration will probably need to be much lower due to the increased inertia of the larger diameter screw.

300 ozin will probably be ok if you are using linear slides and ball screws. It all depends on the friction of your system, which is not something anyone but you can determine. If that's what you already have, try them. If they don't work, sell them and buy bigger ones, not nessesarily in that order... Almost gauranteed that you will be able to make the parts move, but you will find out if they are strong enough when you try to get them to move fast...

Paul


Fwiw, guys are building Joe's new 4x4 machine (which is about 6 ft long) using the HobbyCNC 305 oz motors and the 1/2-10 5 start acme and getting 200-300ipm rapids.

1/2-10 5 start acme with delrin nuts has an efficiency of 75%. Not that much less than ballscrews 90-95%, and a lot less money. Much better than single starts efficiency of about 40% or less.

All great info guys, thanks a bunch! I have made up my mind that the electronics will be the next thing I purchase. I see that the hobby cnc kid does not come with an transformer, question is, the one that they reccomend, with the 305 oz steppers, is it going to be able to supply the system with enough power to run the steppers at thier 35VDC as recomended?
Fatal-exception, I would rather go a bit overkill and not stress anything beyond it's limits if I get a bit carried away with this thing(I have been known to do that) and keep it in budget, and accurate.
Gerry, thank you for the explination, that all makes sense now.( I have never seen a ball screw in person before) I also have determined that after the electronics I will get the screws and additional parts for the crews from dumpstercnc.com. that leaves the slides which will be the big kick in the wallet, but i thin it will be worth it in the end.

If anyone has 12 and 20mm blocks or hardened rods that would work on my router and would like to donate, I'll cover the shipping!! LOL, I think I have a better chance of getting hit by a car. truly guys I appreciate all the help and advice!

ps. ger21 I see you are a moderator, could you change the title of the thread to: First CNC, Need guidance. it seems I may be going with screws after all! Thanks!!

Well, I got some time, and some small stuff done. I have determined the location of the routers new home and painted the area and made a very sturdy table for it by acnhoring 2X6's to my block walls. all that is left to build as far as the table goes is the safety plate between the router and the control area and a set of bi-fold plexiglass doors with a nice looking frame to close it all off. I had planned on putting a post in the middle of the span but it is so strong that I don't see a need to do so yet. I am hoping to get the electronics next. attached are some pics of the router in its new home.

ok, so I took my drawings of my router to a local cnc machine re-builder and he said that I should use servo motors /encoders/amplifiers, not steppers, and that my frame is really weak and it will not be accurate even running a dremel tool as a spindle!! now I am no engineer but, having personally tried to flex this thing (unsucsessfully) I don't think it's that weak. he also said he wouldn't have used aluminum to build it, again, I question why not given the application. so anyway, what are your opinions as far as strength of the frame? am I missing something big, or am I getting some bs off this guy? Now I am starting to second guess myself.

I would say he's full of ****.

I think you have a good start, but don't get discouraged if you find it to be too weak, just add more material. That's the beauty of the whole thing, it's not done until you say it's done.

Paul

My guess is that he's trying to score himself some business. Servos are better, yes, but not necessary by any means. Steppers will do everything you them to do. Your frame is probably more than sturdy enough for what you're doing, and if it racks at all you can use the newly (ish) found method of securing it with a moving knot.

You're looking good! Keep up the good work!

Thanks for the replys, This guy shocked me when he said it was ONLY 2'x5', I'm standing there thinking this thing is pretty big as far as a hobby router goes in my opinion. then I saw some machines he was working on.....freaking huge cnc's, He kinda killed my rush when he didn't have anything nice to say about it. anyway, what is a moving knot?? We will find out if it really works.... hopefully by the end of fall.

i just went back and reread your post,as i had not been following it from the beginning.as i am a machinest i can tell ya,your machine will not cut 1/4 inch deep with a 3 inch face mill in cast iron,which is prolly what the machine re-builder was meaning when he said what he said about using aluminum and servos,...but....thats not what you were building was it? so id say just what others have said , build it as you need it...you said in the first post you were going to cut wood and foam....the re-builder guy prolly didnt know this and was offering some good advice on building a machine which is "build it better than you THINK you will need"....if he did...then GIR was right,hes prolly just trying to get some business, you dont need a cast iron machine to cut foam ,but cast iron IS a must if you are going to be hogging big cutters and deep cuts,your machineshould do what you want...if not....just do some bracing here and there .hey at least you have got a REALLY good start on your machine...im starting to think ill never even get started on one...lol :)

xXACEXx thanks for the input, yeah I told him I was only cutting wood and foam and using a dremel as a spindle, so maybe he didn't understand me correctly, whatever I will continue on and see what happens. I got my computer all hooked up last night, and have a network in my house that I tied into so I can draw on my good computer and cut with the router computer. the mach program is all installed and ready to go, I figure I may as well do what I can while I wait for the cash for the rest of the parts.

anyway, what is a moving knot??Here is the thread (http://www.cnczone.com/forums/showthread.php?t=51485) talking about the moving knot. It's described very well several times in different ways, so keep reading and it should start making sense. As mentioned in the thread, it was originally used in draws to keep them square, but has an excellent use in our kind of machines that aren't always as accurately built as they should be.

Tyler

To me, your setup looks like a good hobby machine. If you stay within your end use goals, it will be fine.

One way to look at his comments, is to ask yourself the same question that we all ask ourselves - If I had a project that needed more power, more precision, less vibration, more speed - what might I change / improve ?

Usually, you can find 4 - 5 things that we all wish we had / could have
- Maybe a little thicker metal parts (1/4 vs 1/8)
- A little better spindle (perhaps kress vs dremel)
- Stronger motors with flatter torque curves (either a good quality stepper or servo setup - personal choice IMHO)
- Better linear motion parts (many options, but we all have to deal with budget reality - no point putting 10 K in motion parts on a home balsa cutter)
- Vibration dampening - could a few pieces of rubber here and there help - you will know when you hear it sing. :)

My brother and I have similar conversation on "how rugged" to make things. He has real journeyman manual machinist training and knows the "right way" to do metal work. His experience is mostly steel and some aluminum. My needs / experience are wood with dabbling into foam and aluminm.

He stocks steel and Al but there is not a 2x4 in his house. I have only a few Al parts (for the router), no steel, but various kinds of wood stock for projects. (if only we lived in the same state).

Anyway, keep moving forward. Just don't buy wimpy motors.

OK, I am back! I have aquired enough cash to get the hobby cnc pro 3axis board with the 305oz steppers. I have one question before I order though. does anyone know if this setup will be able to move ALL 3 AXIS at the SAME time? i plan on doing some 3d shapes to make molds and I need to have the X,Y,Z move together. sorry if thats a stupid question but I just want to be sure before I order.
Thanks

Any drives can do that. It's the control that you need to be concerned about (Mach3?), but all the hobby software controllers can do full 3D.

sweet, I guess I'll place my order then. thanks for the help!!

check this package:
http://www.kelinginc.net/CNCNEMA23Package.html

Thanks for the link kelinginc. I had been to your site previously, after considering all the options, and hobbycnc.coms sale on complete packages. i went with the hobbycnc pro chopper board with the 305oz steppers. (just finished ordering it!!) I did see some things that I may need in the future ie;e-stop button, so ill probally still order something from you in the future.

ger21, all of my drawings will be done in mastercam x2, then sent to mach 2 or 3 for processing. i see that some companys have setup files for thier drivers. does anyone have a setup file for the hobbycnc board that works with mach? thanks!

Well I got a box yesterday from hobbycnc.com!!(only 3 buisness days to be delivered,not bad!) opened it up to find a very well packaged kit and steppers. after removing all the bubble wrap I did a complete parts check and everything was there! now I have to get a xformer and some home/limit switches and I should be set in the electronics area. anyone have any suggestions on these items?

well, in light of all the rain and storms we are getting at the moment I took a break from the french drain fiasco i am working:confused: on and decided to solder up some parts. :)2 hours later I have all the proper voltages on the board and my vRef. is set up for all 3 axis, and best of all NO MAGICAL SMOKE!!:) this kit has been VERY easy so far. now I need to find a xformer and intall it in my case. I am a very happy camper so far.

here are some pics of the HobbyCNC board and the begining of my enclosure.very easy to build so far. transformer is ordered and on it's way.

I'm building a cnc router table 4' x 8' for wood with 3-305oz servo motor with drive belt
I'll use a 25mm ball screw but don't now if I should pick a 10 or 20 pitch

I need some one guide me, please anf thank you!

oscar

hey oscar welcome to the zone. I wish I could help, but I am also new at this. this thread has been quiet for a while but maybe someone will chime in and help ya out. good luck!

ok, well I got my xformer and went to work. this is what I ended up with. everything worked fine and all voltages are good. after finishing up this kit I would give the instructions a 9 out of 10 and the completeness of the kit a 9 out of 10 also, it would have been nice to get the heatsink compound and transformer with the kit instead of having to make a second order for these items. I hope it works as easy as it went together.

OK, I may have a lead on a small hydraulic collet system that would let me use a larger variaty of bits on the router. My question is this; what type of spindle motor would i be looking for so that i can have direct drive? I was thinking a dc motor would be good because I could change the rpm. remember i am not doing anything like steel so my loads would not be that great, however I do think I would need a high rpm to do most of my work. any thoughts or ideas??

ok, the chuck systems are from Sandvik Coromant, http://www.coromant.sandvik.com/
i believe one of these two chucks are the one that would work best for my application
Coromant Capto, pencil type High precision chuck
or
HSK, pencil type High precision chuck Cylindrical shank

anyone using them or have experience with them?

Anyone??

ok, I'll try another question. is there any other suppliers of hdpe other than McMaster Carr? I am going to need either 2- 3/8"x30x6'-0" or 3-1/4" of the same size to make my vaccum table.

Oscar The pitch you are looking for is much to fine for your application. 5 pitch (.200 per rev is the proper screw and readaly available at a reasonable price. I have 50 plus years in the manufacture,operation and sales of Machine tools and would be glad to help you. Contact me at melatthewhitehouse@cox.net

Mel

Rcpilot
The best plate to use for vacum tables is ground aluminum tooling plate available at most metal suppliers. This plate is flat and parralell to a close tolerance.
Mel

Mel White, do you have a link so I can see what it looks like? also, remember i am primarily going to be cutting foam, lite ply, and balsa wood.

anyone got any info on the collet system mentioned in post #59?

ANY METAL SUPPLY BUSINESS SHOULD CARRY ALUMINUM TOOLING PLATE. iF YOU ARE ONLY GOING TO USE YOUR MACHINE AS YOU DESCRIBE YOU MIGHT TRY CABINET QUALITY PLYWOOD WITH A DENSE CORE. CHEAP AND I BELIEVE IT WOULD WORK FOR YOU. YOU WILL NEED TO DRILL A LOT OF SMALL HOLES ON A PATTERN NOT OVER .062 DIAMETER TRY .500 BETWEEN HOLES TO START YOU CAN ALWAYS COME BACK AND DRILL BETWEEN IF NECESSARY.
MEL WHITE

attached are my updated plans for the router along with some sketches of my idea of a vaccum table. I wanted to be able to have a "grid" that i could select where i wanted the vaccum to be applied. this is where i came up with the hdpe material. also as a note when I am using the vaccum table the weight of material on the table will be 5 lbs at max.I will have a solid mdf table to be used with heavier materials or materials needing additional hold downs.

Ok, I have another question.(probally another dumb noob?) what differences would I see between these two acme rods, 1/2"-10 5 start, and 1/2"-8 4 start? If my understanding is correct, I would see faster rapids with the 1/2-8 but im not sure.

I also have some problems as a begginer. I need to decide about step motors&drivers, so I need an information about the question bellow.


I would like to know how fast (max. speed) can a spindle go in a material like
MDF or Extrudepolistyrene (XPS).
Not theoreticly, but really from you ekspiriences.

x mm/s = ?

1 (inch) divided by 10 (threads per inch) , times 5 (number of starts) =.5
1 (inch) divided by 8 (threads per inch) ,times 4 (number of starts) =.5
..so i would guess if your motors can turn a thread like that, you would do fine with either one...any particular reason you wanted one over the other? price? availibility?

Ok, I have another question.(probally another dumb noob?) what differences would I see between these two acme rods, 1/2"-10 5 start, and 1/2"-8 4 start? If my understanding is correct, I would see faster rapids with the 1/2-8 but im not sure.

Both are two turns per inch, so speed would be about the same. The one with higher efficiency would be the better choice, but they are probably very close.

XXACEXX, no particular reason, I saw on other threads that some were using one and others were using the other and just wondered if I was missing something in my design.thanks for the replies. I have 305oz steppers all up gantry weight should be around 50lbs or less.

Ger21, thanks for verifying that. I was starting to think nobody was watching this thread anymore.

what do you guys think about this router mated up with the above (post #59) hydraulic collet chuck? I can make an adapter to mate the two, it seems like a decent router.
http://www.lowes.com/lowes/lkn?action=productDetail&productId=117513-67702-KM12VC&lpage=none

what do you guys think about this router mated up with the above (post #59) hydraulic collet chuck? I can make an adapter to mate the two, it seems like a decent router.
http://www.lowes.com/lowes/lkn?action=productDetail&productId=117513-67702-KM12VC&lpage=none

First, do you have any idea what that chuck costs? I'd guess more than the router. And second, how do you plan on mounting it to the router?

Yeah I'm pretty sure the chuck is more than the router but it may be very discounted or a freebie. we plan on using a lathe to make an adapter to mate the two up. it should be a really sweet setup. :)

Ok, the other spindle I was looking at was a kress 1050fme. problem I am running into is I cant find a US dealer, or a price on it. so anyone know where to look for a US dealer? anyone have experience with this product? and finally how would I go about adding a way control the rpm through mach3?
Thanks!

Or this one: http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10051&langId=-1&catalogId=10053&productId=100634368&N=10000003+527284+10106010

Well, the spindle choice is no longer an issue. I stumbled upon a new freud 2 1/4 hp router with variable speed. I lucked out and got the whole thing for $89.00 (they were clearancing the freud line at lowes $200.00 list). I think thats a good deal! I compared the specs to the hitachi router and they are similar except that the freud has more amps and 1k rpm less on the low end, but same high end rpm. I'm glad thats over with! another piece of the puzzle in place, next stop.. linear slides.

glad ya found a router! been keeping up with your build but had no experience with any routers..so i didnt comment.....glad ya found one

glad ya found a router! been keeping up with your build but had no experience with any routers..so i didnt comment.....glad ya found one
yeah the only thing that kinda sucks about this router is that it's 4"in diameter...slightly larger than a dremel LOL, oh well i think it's worth it.

ok, I am wanting to be able to use mach 3 to activate relays to turn on/off my spindle and cold air (coolant). Can anyone provide a schematic of how to do this and pictures? my spindle is rated at 13 amps and the cold air selenoid will be about 1 amp rating. is there a DIY way to do this or do i have to get something like the xylotex board?

Ok, I got another question, does anyone know what series of collets this freud router uses? I couldn't find it in the manual anywhere, and it's not marked on the router. the model number is; FT1702VCEK. any help would be greatly appreciated.
Thanks

Ok, well after looking at the hydrogrip system I determined that it wouldn't be ideal for my application. the shaft would end up being about 6 1/2" beyond the router which is too much for my liking. I ended up finding a ER collet chuck that will require NO modification to anything to make it work and the length will work out to what I need. I alos ordered the Pillow blocks for the acme screws and the electronic components to build relay boards to actuate the spindle,coolant, and vaccum. the air selenoid and regulator are also on there way. :) looks like I am finaly going to be making some progress again! My dad has an enco mill that he hasn't used since he got it about 8 years ago, sooo..I talked him into putting in my garage so I can play with it. it may also be the next item to turn into cnc. gotta finish this project first though.

well the good ol UPS man deliverd more parts today. I got all the bearing flanges for the acme screws and the air selenoid and regulator. all of this came from surpluscenter.com. it may only bee a few pieces but it is one step closer to a working router!:)

any part is progress right? :) so......




good job! :)

Well, I just bit the bullet and ordered all of my linear slides from vxb.com:confused:I am still in a state of shock as this is the most $$ I have spent in one place in a very long time. I hope I won't be dissapointed and that everything makes it's way from cali to PA unharmed. (nuts) gosh I hope this thing will work well after all this. Hey, I got a free digital vernier caliper for spending all my money there though.:confused:

Ok, I got a question before my slides show up, what is the best way to mount the supported rails for the x axis so there is no binding? here is a link to what I ordered; http://www.vxb.com/page/bearings/PROD/20mmLinearMotionSystems/Kit8389 What is everyone using as a reference point so set up all 3 axis so they are parallell and perpindicular to eachother? is there anything else I need to be aware of before I start drilling and bolting?

If you can give me some info on your machine construction I can help you with technical support.

mel

mel,the thread has all of the construction info on the router with pictures. please read the thread and if you need more clarification on something I'll see if I can explain why i did what :)

I GOT SLIDES!!! I came home today to a VERY heavy cardboard tube from vxb.com opened it up and everything looks great! No damage to anything and very well packed. I'll post some pics once I start the assembly process. The next item to order will be the acme screws. I plan on ordering the 1/2"-10 5 start screws from mcmaster-carr unless anyone can direct me to a cheaper place! Does anyone have any thoughts about using these particular screws for all the axis before I order them (work well, won't work at all)?
Once they are ordered I am committed to using that pitch/start. if things keep going this good I'll be running parts by mid december!

I GOT SLIDES!!! I came home today to a VERY heavy cardboard tube from vxb.com opened it up and everything looks great! No damage to anything and very well packed. I'll post some pics once I start the assembly process. The next item to order will be the acme screws. I plan on ordering the 1/2"-10 5 start screws from mcmaster-carr unless anyone can direct me to a cheaper place! Does anyone have any thoughts about using these particular screws for all the axis before I order them (work well, won't work at all)?
Once they are ordered I am committed to using that pitch/start. if things keep going this good I'll be running parts by mid december!
I can't find the info on your machine? Good choice and excellent buy on your round ways.
Mel

Mel, the design drawings are on post #66. They are in AutoCAD 2008 format. if you don't have acad you can download a viewer from here, http://usa.autodesk.com/adsk/servlet/mform?siteID=123112&id=9131297
you don't have to register to get the program. I guess I should have clarified that. soooo, take a look!! remember this is a medium duty machine with NO STEEL cutting abilities.

I can not find thread #66
Mel White

POST 66 in this thread, not thread #66. look in the upper right hand corner of the post. this post is #93

thats a pretty good set of plans by the way,you draw em?

How do I get to 66 I can scroll to 83 only.?
Mel

At the upper right corner of the most recent post is a box that shows page numbers. Click on page three and scroll down to post #66.

CarveOne

Well, I've been a bit under the weather lately so today I felt good enough to work on the router a bit....4 1/2 hours later I have a completed x axis slide system with the gantry attached. :) Best part is that when I push the gantry with one finger, easy constant pressure, it moves easily and continues to move for about 8" after I let go. I loaded up the gantry with more weight than what will be on it when done and it still moved easy, just took more inital force. I figured I'd go for broke and threw on the top frame and measured the height difference at the extreme ends of the x axis. the error was about 1/32" over 5'-4"!!not bad IMO.:banana: ok well enough rambling here are some pics! I am officially AMPED UP over this thing now!

Mel, Here is another copy of the file if you cannot find it anywhwere:)
xxacexx Yes I drew them myself.. a couple times till I figured out what i wanted.

OK found your drawoings and pictures.Excellent Job. What are you going to use this machine for? If your frame is straight you can mount an indicator to your Gantry and run it up and down the frame to check to see if they are both on the same plane if not you can shim up under your way support to bring it close. A thirty second is not acceptable to me. The ways you bought are an excepptional value. What are you doing on Y? Ball screws are not expensive over a long period and probably for your use you could use Rolled screws which are cheap. If you are commtted to Acme screws you should look into Nylon nuts as they will outlast any metal nut and permit you faster travel. For the size machine you are building you need at least 200" per min or even faster for your rapid traverse. Compare this with your computer that never is fast eneough and we always want them to operate quicker the same applies here as you use your machine you will find that the faster is better. You will spend a lot of time building this machine so do it right Ball screws is the answer.

What kind of control are you using? What motors and drives?

I will be happy to share some of my experience with you.

I am building a high precision 5 axis mill for a Jewler to use in making jewelry. Overall accuracy will be under 0.0002. Travels X 10" Y11" Z 5" Gantry type. I am retired but have to keep busy.

Mel White

MEL, Glad to see you got the file finally! The 1/32" figure was with no bolts or shims just clamped down, I havent even ground down a few welds that probally are causing the error. I was just impressed the the overall straightness of the frame so far. believe me 1/32 is NOT acceptable to me either, I will have it right by the time all is said and done. I have committed to acme screws and will be using delrin nuts from dumpstercnc.com. I am trying to get up to 300ipm rapids out of this setup. controll is mach3 drive is a hobbycnc pro 3 axis and motors are 305 oz steppers. Computer is good for the speeds. as for the y and z axis, both are 20mm shafts on closed trucks. here is the link.http://www.vxb.com/page/bearings/PROD/20mmLinearMotionSystems/Kit7705 I will be making my own flanges that are similar to these. http://www.vxb.com/page/bearings/PROD/20mmLinearMotionSystems/Kit7231. I will use the same acme rods to translate the motion.

More progress, I got to cut out my mounting flanges today at school along with cutting my linear rods to the proper lengths. I also got my collet chuck for the router and some delrin to make miscellanious parts as I need them. My buddy and I also decided that we are going to make dampers for his steppers and mine, so thats in the works also. I have plans for this evening so I'll post pics and hopefully get some more done tomorrow. The goal is to have all the slides done by mid week.

Today I got the y axis slides all setup and started on the z axis. this is the hardest part so far of building this router, very time intensive! but well worth it.here are some pics of the progress.

More Parts are on the way! I ordered all of the anti-backlash nuts,clamps, and couplers from dumpstercnc.com last night, along with the acme screws (1/2"-10 5 start) from McMaster-Carr. Aside from designing standoffs for the steppers, a router mounting system and tooling, I think that I have everything ordered to make this thing move. all 3 axis move with an easy push of one finger from limit to limit so it should be good. I just hope the acme rods don't come in bent!

You will find that 1/2 screws are way to small and will give you nothing but trouble. For the travels you have I would use nothing smaller than 3/4" and preferadly 1".
Mel White

They are using the 1/2" rods on the joes routers and they are working fine. I am pretty sure my ganty weighs less and has less friction than the joes. just to lower the rpm of the shaft I went with the 5 start threads. Remember this is not an industrial router. besides that it's all I could afford.

Are you talking about 5 start threads or 5 threads to the inch. 5 starts are 5 separate threads. You are doing a great job on your machine and you can be really proud of what you have done.
Mel White

1/2-10 5 Start, here is the mcmaster part# 98940A627 www.mcmaster.com

Well, I have had a bit of a setback, I was involved in a car accident on the 18th and it beat me up pretty good. I now have everything delivered to the house to finish the build but I am in no shape to work on it. :( When I start to build again i'll be sure and post pictures, but it may be a few weeks untill I can get back into it.

Have not posted but have been following your thread. You are doing great, I really like your machine.

If you don’t mind I think I will steal some of your ideas and give this a try in 8020 with belt drive. Still trying to decide which direction to take on some aspects. Have some time, won’t start until after new year, and will only be able to throw a few hundred a month at this for the first few months.

Sorry to hear about the car mishap, know how you feel, I rolled a Chevy Nova three times many years ago and can still remember feeling like someone had me in a punching bag for a week.

Have not posted but have been following your thread. You are doing great, I really like your machine.

If you don’t mind I think I will steal some of your ideas and give this a try in 8020 with belt drive. Still trying to decide which direction to take on some aspects. Have some time, won’t start until after new year, and will only be able to throw a few hundred a month at this for the first few months.

Sorry to hear about the car mishap, know how you feel, I rolled a Chevy Nova three times many years ago and can still remember feeling like someone had me in a punching bag for a week.
Glad you like the machine, go ahead and give it a shot, I don't mind at all. I had originally thought about doing a belt drive, but changed my mind. I would love to see the results of a belt drive system, do a build thread! I like Novas, my dad had one when I was a kid. yeah I don't feel that good, it was a bad accident, head on impact. it sucks.

ok, I am back with another newb question. how fast in rpm will my steppers turn? I am able to hook a drill up to the acme rod and run my x axis at 550rpm with no whip, no resonating. I understand that resistance of the moving parts and all plays into this number but I am just curious what is the max rpm for a stepper? I wish I would start feeling better so I can get this thing making chips!

rcpilot82,
Looks like you will have a very nice machine when your done. Hope you start feeling better so we can see it work with you.
I'll be following for sure.

Bud

ok well my previous question has been answered. I hooked up the x axis tonight to check it out while waiting for more hookup wire to do the other 2 axis. after a little motor tuning in mach3 I am getting consitant 280IPM rapids! I think there is some room to mechanically improve some things as well so I should be able to hit 300 no problem! It's amazing to see all that work finally start moving with a G00 and G01 instead of me pushing it along! I can't wait to get the rest done and see it move all 3 axis in concert.

congrats on getting it to move under its own power! and thats a pretty fast rapid also,glad to see it coming along :)

Congrats on your progress! I picked up a number of ideas as I read through your thread from the top. It's been very helpful. Thanks!

I am building a similar sized machine using 80/20. My build log is at: http://www.cnczone.com/forums/showthread.php?t=68720. I sometimes think that I decided to go way too big and that I'd encounter problems like screw whip, rigidity issues, etc. Based on what I've seen in your build I am reassured that there are solutions within a hobby budget to these potential issues, and that I can still end up with a good cnc router to build my rc planes.

Looking forward to see a video of your router in action!

cheers,

debetto

debetto, I did LOTS of lurking around here on the zone before I decided on my build. I like you was unsure of my design capabilities and didnt have the ability to do a "trial and error" with parts. i am glad with the router so far and think it will do what i designed it to. good luck with your build!

Just to make sure I did this right, could someone verify my understanding of microstepping and mach3? I have steppers that are 1.8degree or 200 steps per rev. (1.8x200=360) I am using 1/4 microstepping on the hobby cnc board, so every one step is broken down to 4 steps. I have 1/2-10 start screws that require 2 revs to move 1".

so here is my understanding; I take 200(stepper) multiplied by 4(microsteping value)=800
then since I have to make 2 revs to move 1" with the screws I multiply 800 by 2=1600
therefore, it takes a total of 1600 steps to move 1" for my setup. this is the # i put in the motor tuning section of mach3. is this right?

here are a few pics of the start of final assembly

Nice! Are you planning on coming out with your own rc kits? That's what I am planning on doing with my CNC router.

debetto

Nice Looking Machine.

Joe

debetto, Yes I plan on producing "foamies" and making indoor competition planes for my buddy. I am not trying to make a million, I would just like to fund my obsession....uhh hobby. I also would like to get into some composites and wood kits. guess I have to get the ting running first :) as of now for basic operation all thats needed is to wire the y ans z steppers, and mount and wire the limit/home switches for the y and z. To finish the router as planned I have to make 3 relay boards (spindle,air coolant,and vaccum) and install the above 3 systems. I figure if I can get it to run I can use it to make mounts for everything else.

Joecnc, Thanks for the kind words!

here are a few more pics,

Well, today has been a buisy day. All of the steppers are wired, limit and home switches are mounted and just need final termination. Mach 3 is set up and ready to roll. So I went into Mastercam x3, wrote a quick program, and sent it to mach3. powered up the hobby cnc board, all 3 steppers came online, moment of truth.....cycle start..Holy crap it WORKS!!! Now all thats left to do is the cold air setup, and spindle on/off electronics. This has been a great experience so far and it's awsome to see all 3 axis moving together under thier own power! I'll post some pics tomorrow.

well, I ran into a problem here. I am having issues with my home/limit switches! check out here for the link to the thread; http://www.cnczone.com/forums/showthread.php?p=540338#post540338
anyone got any ideas? IM SOOO CLOSE!!

UPDATE! Limit switch problem resolved! the final piece left to fabricate on this puppy before having some fun is the relay boards to turn the spindle, cold air, and vaccum off and on. collets and tooling are on the way also.

well I finally got to run some parts off the cnc! I started out by cutting a plain foamy (indoor RC aircraft) which went well. I was so excited I didn't get any pictures of that. I then kicked it up a few notches and re-designed an existing foamy so that it would be lighter by milling out pockets in the airframe. I did get pictures of those, so here they are!

Well I am getting the bugs worked out of my router and figured I would make some "upgrade" parts to stiffen up the z axis and to clean up my stepper mounts. I had a bunch of 3/4" acrillic laying around from old car stereo installs and figured it would be great for my parts. these are the first parts that I have run off this machine with NO problems at all. Now I have to find time to finish drilling and tapping some holes and put em on.:) so here a few pics of the parts fresh off the router.

Here is another version of the foamy that i also cut out this week.

What bit did you use to cut the foam with?

I used a .25 4flute cent.cutting end mill for the pockets, and a .0625 2 flute cent.cutting end mill for the rest.

nice parts !

good to get to use the machine huh? on the 17th you were having problems and now you are making parts

good job!

Wish I knew how to weld. That machine looks awesome.

Thanks for the kind words guys. xXaceXx, I am still having the issue with the limit switches but have turned them off for the moment untill I can sit down and go through it step by step. I am really having fun with the router, now I need to make some stuff to sell to make it pay for itself!

Looks like alot of fun, I remember finally finishing my machine and being able to cut the first part, It was so exciting! Great job!