Cutty Shark I

[LeeWay]

Okay Guys. Its time to get busy. Since I first knew that I had to have a CNC router just a mere few weeks ago (Thanks CNC Zone) I have gobbled up as many different designs as I possibly could from here and elsewhere on the web.
I also took note of the items that I have on hand and developed a design that I want to use for my initial setup. Design has changed several times even after buying some of the materials that won't be needed now. I can see that it might pay to get the design down on paper first.
I make blade guards for tablesaws. The guards are called Shark Guards. Ergo the play on words with the name of this machine.
Anyway, the Cutty Shark I will mainly be for cutting polycarbonate and thin aluminum sheet. I have the basic frame parts already, so these dimensions are what I am hoping for. X axis = approximately 36". Y- axis = approx. 20". Y axis = maybe 4" or 5".
I'll add more details a little later on. Here are a couple of images to get started with. Comments and suggestions are absolutely welcome and the sooner the better.

[joecnc2006]

Looking at your drawing, do you really need the two top interior bearings? I would think the on the top the upper vertical bearing and outer horizontal bearing will work to hold it from moving side to side then on the bottom the lower vertical bearing is the only one needed to keep the gantry from upper movement.

Joe

[LeeWay]

You are probably right. This is most likely too many bearings. It would actually be 10 bearings per side with this setup.

I wanted to make each side of the gantry sorta stand alone on its own without falling off if the gantry weren't there. My thinking is that this may actually reduce any chance of racking. Therefore, I think the top three are a must for starters.
The gantry will be pretty heavy itself. All the parts are some nice steel that I had on hand. The 2" x 2" x 44 7/8" tubing is nearly 3/16" thick and the flat bar is 3/16" x 4" x 44 7/8". The end angle iron is 3" x 3" x 1/4" x 24 5/8".
I was thinking because of this, there would be very little chance that the router would want to lift the gantry anyway, so I might get away with just some delrin. This could be mounted and adjusted a little easier than the bearings.
I bought 100 bearings on Ebay. I have about twenty peices of 3/4" x 3/4" x 4' aluminum square tube and some brass rod on hand already. This was another reason for overkill in the drawing.
I have a mini-mill, mini-lathe and 4"x6" bandsaw to make the build much easier.

Some other details of this build that I have bought are the Xylotex driver board. Three 270 oz. steppers from Home Shop CNC.
A 24 volt power supply, assorted bearings, shaft couplings, fan, bushings switches and what not from Surplus center.

I bought some 5/8" 8 acme rod and 6 square brass nuts from Mcmaster Carr.

I haven't yet bought the license to run Mach 2, but that should be the last thing major that I'll purchase. I managed to pick up a couple of double bearinged 12" long new THK rails on Ebay for the z axis.
The basic design is one that I should evenually be able to retrofit THK rails on for the other two axes if I am able to find any deals on them.
I'll be makin my own contoller box out of aluminum. I'll powder coat it when done. Any suggestions for initil switches lights bells and whistles for the box?
Thats it for now. More updates soon. More thoughts and suggestions are welcome.

[CNCadmin]

Here is my idea for ya-

[LeeWay]

Thanks for a peek at that bearing design. It looks good and simple. I like simple and good. I have had this 4" zinc plated flat bar laying around for a long time. At least I have managed to cut it into shorter pieces now. I wanted to see how straight I could get it mounted, so I put one side together last night. It came out great. Its as straight as my T-square in both directions. I will use it for starters. I should have the frame complete this evening and will add some more photo's then. It feels good to start building it already, rather than just spending money and amassing parts.
After lifting the frame and track assembly for just one side, I am starting to think that this thing may weigh nearly as much as some of these smaller MDF rigs.

MDF and I do NOT see eye to eye. If thats all there was to cut in the world, My tablesaw would be on the curb.

[LeeWay]

Here's the next installment. I was able to get all my holes drilled for the 5/16" carriage bolts that hold the frame together. They also hold the rails on. Everything came out as square as I can measure. I had it leveled up in the picure and the frame is dead level. The rails tightened up great as well too. I am a happy camper at this point.
I had originally intended for the machine to sit on this stationary table in the corner of my shop. Now I know that it has to be on casters. All sides of the machine will need to be accessible at times. Plus a steel framed base with casters will actually have less of a footprint.
I ordered 4 casters from the Surplus Center. They had what looks like a great deal on them.
Here are a couple of photo's so that ya'll know it did happen.

[LeeWay]

I have just a little more progress to report. I worked on my all in one control panel this afternoon. Got a good start on it. I'll get it all together soon. I have a micro motherboard that will go in here. The fan on the bottom of the power supply is nearly as big as the big fan in the photo. Don't think I'll need to move quite that much air. I have two smaller normal size fans that I'll stick in there somewhere.
I will need to put a filter on the outside somewhere as well. Perhaps on the back. I won't be cutting ANY MDF with this thing. No fine dust. I use a dust collector in my shop too, so that will help. I will be hooking up a dust port for the router as well.
The box is .063 aluminum and 3/4" square aluminum tubing. All drilled and tapped with 10-24 screws. Could have used rivets, but just wasn't that sure I wouldn't need to take it back apart. Thought about powder coating it, but now that its going together....
The dimensions are 18" wide x 15" tall and 12" deep. Should be plenty of space in there. Thats it for now.

[LeeWay]

Todays update is a little more done on the control panel.
I found out that when I sand blasted the front panel on one side only, that it cups the panel. Like the glass beads actually stretched that side. Wow! Learn something new every day.
I reckon I'll have to blast the inside of this panel too.

I found some hammertone paint in a charcoal color that looks nice. I think I'll use this on the whole machine. Control panel and all.

I never thought I was going to get the computer part to work. This is my fourth mother board. The others were just spares from older computers. I could not get the bios to load. Guess those are bad. I picked up this computer monitor at a repair shop. They normally throw these little things out. I think it will do for this.
I want to try out Turbo CNC first. Got it loaded and I'll run with that first. I think its capable of doing what I want done.

What type of controls, switches and leds would ya'll suggest for the control side of the panel. I have the 3 axis Xylotex board. I just have the normal stuff for the computer side. I want to wire the big power supply up using an old socket from another power supply. Then I'll have a detachable cable. Both power cables will then plug into a surge protector with a switch.

Thanks for looking and suggestions are always welcome.

[LeeWay]

Todays update is short, but a little progress. I have worked a little more refining the control panel. It will sit on a shelf about 8" higher than the bottom bracing on the cart in the pics. I may put the little monitor down there as well. It would be tilted to be seen from a standing position. Keyboard will be covered with a big ziplock bag or maybe some press and seal. That stuffs pretty neat.
Anyway, here's the pics of the cart after I got the bottom welded up. The legs are some sort of overhead door track that I picked up. The bottom frame is just part of an old bed frame. I got these nice casters from Surplus center for $4.95 each. These are very good casters with a 200 + weight limit each. Nice rubber tires. These are made in Australia.

[LeeWay]

Well, I didn't wait.
I have been working on the control panel and had some computer problems, switch failures, new power supply short on the computer, wire routing issues, designing on the fly setbacks.
All in all, just about what I expected.
Anyway, I could not resist the urge to test the motors. All was going wll and my son was repositioning the motor and touched one of the untapped center wires on the x axis to the controllers case. This must have knocked a smoke seal loose, because my Xylotex board spilled some out. He felt bad about it, but it wasn't his fault. I should have tapped up those wires anyway.
The good news is that everything else seemed to be working fine in Turbo CNCjog mode.
I have possed another question on the Gecko drive forum here. I will send this board back home for possible fixing, but I was wondering if I should buy a second board as backup.
My motors are rated at 2.8 am bipolar, so this is just a little high for the Xylotex anyway.
I'm not sure what all I need to go with the Gecko's instead.
Any input would be appeciated.

Thanks.

[ger21]

A Xylotex (and Geckos as well) will die instantly if a motor wire is disconnected with power applied, or from any short of the motor power wires. Jeff @ Xylotex will repair it for a reasonable price. If you're careful, you shouldn't need a spare. If you think you'll need a spare, is 1 spare enough?

[LeeWay]

I may just wait on an upgrade to the Gecko's. I'm sure I will want to go that route eventually.
I have contacted Jeff and am awaiting some info.
I think at the stage that I'm at, a second board would be the way to go.
If I screw up again, , time won't be a factor. When I upgrade, I'm sure there are many guys that would like to have the drivers at a reduced cost. Assuming I don't blow them again.
I went through all the research it took for a niovice to get this hooked up and running just to let a stupid mistake set me back. Well, I won't make the same mistake again.

GUYS, cover your unused wires! See, now I can finally contribute some useful information to the Forum.

[buscht]

Lee, the Xylotex will work great with your steppers. That's the setup that I'm using and have been very pleased.

I have two boards, I managed to blow them both up at different times. All my fault. Once I figured out what to do I haven't had a problem in over a year.

Nice thread and thanks for sharing the design details.
Trent

[ViperTX]

I wonder if the Rutex boards will also die instantly....hmmmmmm wonder what their circuitry really looks like....

[ger21]

Gecko has new drives coming out soon that are nearly invincible... G204.

[LeeWay]

Well thats certainly the kind that I will be needing in the future.
I did place another order for a second Xylo board today. As I said, it was all working (jogging) fine. Everything is setup in the panel for them already anyway.
I am over that real bad feeling in the gut already. I will try my best to keep Murphy out of my control box in the future. Now, on to the easy stuff. The machine (he said while crossing his fingers).
Thanks Guys. Ya'll are a tremendous help and a good influence.

[LeeWay]

I made a little progress. I worked some on the bearings for the x axis. I cut the sides out of 3/4" aluminum. This is just what I had on hand that was bg enough, hopefully. I also managed to turn the ends on the x lead screw and get it in place.
I used 3/4" aluminum bar for the top bearing holders and square tube for the guides on the sides. 3" angle held it together.
I made a bunch of brass bushings to fit the bearings and they run nicely in the channels I milled (cut) out for them. I can see just from testing these on the rails that my initial design had far too many bearings. I figured it probably did. Its generally easier to remove elements of a design than to re-engineer to accept more later. Still easy to do with the holders I used. I doubt that there will be any racking. These outer guides are 10" apart. The weight bearing rollers are 8" apart. That part felt good to get done.
In the process, my backup Xylotex board came in. I will indeed wait to do the motor turning test now.
Check out some of the photo's. Its starting to look like something.

[LeeWay]

Today's update shows a little progress. I got the gantry up and running somewhat. I addedd some adjustment possibilty on both sides of the bearing holders and gantry uprights. I will need just a little to preload the side bearings.
I have figured out also that I need some x bracing on the legs. Making this an all in one cart type CNC router has its drawbacks, but seem to be few so far. I will have to have screw adjustable feet for when the machine is in use. Have to level it up to use it. I guess this is normal with any of them though.
Anyway, here are some pics to check out. I am making headway.

[limbo]

Lee,
You are making great progress! Building a lot faster than I am.. At this rate you'll be done next month
Out of curiosity: I noticed your gantry base consists of two seperate L-angles. Doesn't the gantry skew if you hold one leg and push the other? If so, you might want to fill up the room between the angles with a plate or something?

greetings,
John

[LeeWay]

Thanks John.
The Gantry really doesn't try to skew yet. I was planning on adding a plate in the center to catch the drive nuts. There are two cap screws on each end of the angle. It is fairly solid. We will see if this will be sufficient. I may need to add some 4" flat steel to the outer portions of the angles just to insure that it stays square.

I have another question. Duh!
I am planning on simply putting the motors on in a direct drive configuration with Lovejoy spider couplings. The rod I am using is 5/8" 8 acme thread. I have two square brass nuts for each axis that I will kinda preload. Will I have enough torque this way? I know this will keep the speed up, but only if the motors can turn the thing. At any rate, I think I will test this x axis before I finish the rest of the build. Make sure my ducks are in a row.
Do any of you guys think this kind of stuff is fun? I am having a blast, even with some minor setbacks.

[ger21]

You have to be careful with larger diameter screws. As the diameter gets bigger, the torque required just to spin them goes up fast!!

[limbo]

I think you will have plenty thrust. I run my current router at 1:1 gear ratio on a 4mm pitch leadscrew. 8tpi is rougly 3mm pitch. My steppers are weaker than yours, so you shouldn't have a problem. Instead of a flex coupler I used two pulleys and a belt, keeps the stepper inside the machine and allows to alter the gearing if need be.

John

[LeeWay]

Thanks Guys.
I did get a little more done on my gantry. I redid the bolts that hold my bearings in. I had them threaded into a tapped hole in the aluminum angle. A couple were not dead center with the brass bushings, so I bored a larger hole in alignment with the bushings. I then used longer bolts and nuts. This was the right thing to do. Now the gantry will roll the entire length of the x axis with just a slight push. Kinda like a roller skate.
It is amazing now how well it glides being as heavy as it is.
I also have the drive carriage mounted. I had bought some square brass nuts to use, but these really seem to have too much slop for my liking. I have some delrin and will try that. I did get a makeshift tap made out of some of the 5/8"-8 acme rod.
No pics yet.
I was reading a thread somewhere at CNC zone the other day and a fella was looking for some connectors that could be used repeatably for the motors.
I think I have found what I will use. They are the four wire Hoppy connectors used for hooking up the lights on a trailer. About three bucks each at a local auto parts store. Don't think these are available outside the US. I think Germany had better connectors. I had a popup camper while over there and for the life of me, can't recall the connector type.
Anyway, I think these will fill the bill for my needs. Pics will come a little later.

[LeeWay]

Just another small update. Been busy, but not with the router. Well, not very much.
I made a drawing that kinda shows the design to this point of the ganty bearings and such. I am somewhat proud and glad that it works so well. We'll see how it does undder power.
I was working on getting the lead screw ends turned down. I was also figuring out the motor mount.
I was able to install a manual crank on the lonely end of the lead screw. I think this may just come in handy. I had bought two of these for another project from McMaster Carr. They were about $5 each. Just pot metal, but look great powder coated.
Anyway, here's how she sits currently.

I am editing this illustration. Can't see too much as a JPG. I am including a link to a Flash image. It can be manipulated a little better.
Flash File.

[LeeWay]

A little more this evening. Here are a couple of pics and a Flash video of the first powered movement of the gntry. Okay, not powered by the stepper, but still moving right along. No sound with this. It is also rather large.

For those that may nly have woodworking tools, I show the last two pics. Forget that these are mounted in a Mini mill. They could be in a drill press. I used a Forstner bit and a brad point bit to mill out the aluminum block for the motor mount. Aluminum can be done with woodworking tools. I also cut up the 3/4" plates on a Ryobi BT3100 tablesaw with the stock blade. It works really well. Judicious use of candle wax is suggested to give very smooth cuts.

Video.

[xairflyer]

Interesting to know a forester bit will cut ally.

Could'nt have been a standard blade in your table saw was it !!

[LeeWay]

The Forsner bit needs to be sharp and preferably NOT Tin coated like the one I am using. This coating doesn't work the best for aluminum. You have to take it easy with it, but it will shave off foil thickness chips.
The blade in the tablesaw is the one that comes with the Ryobi BT3100. It is made by Freud and is a 10" 36 or 40 tooth carbide tipped thin kerf blade. Nothing special about it. You have to go a little slower than with wood, but it cut it nearly as clean as the mill did. I satuate the cut line with candle wax.
Of course I had a top quality blade guard with dust collection on it, but thats another story.
I don't think they sell these BT's over in your neck of the woods anymore, but it is one amazing saw. Dirt cheap too. They nearly pay you to take one.
If anyone is interested in just what this little saw can do, Google a search for BT3Central and check out Sam's site. Its where I hang my hat.

[xairflyer]

What are these Ryobi power tools like, I do see them now and again over here but generally thought they were not very good, maybe I am wrong.

[WP1]

Cutting *some* aluminum can be done with woodworking tools. There are many grades of aluminum and some are soft and gummy and are a pain to cut even with "proper" tools. The harder grades fare better though the -T6 temper grades get pretty hard.

I've always had low expectations of Ryobi myself, staying with Makita and Milwaukee and Porter-Cable.

Last year I needed a small buffer to wax and polish my truck and I ran across a Ryobi 6" RO duffer kit complete with case for $20. I figured at that price it was disposable if I at least got one good detailing out of it.

As it turns out it's really pretty decent, more than adequate power decent size and ballance, really nothing to complain about. So it seems that at least some of the Ryobi products aren't bad.

Pete C.

[LeeWay]

The aluminum that I use mostly is 6061. This isn't real soft, but not the hardest either. I don't recall what the temper was on the 3/4" plate. If I was going to be cutting a lot of plate, I might look into a specila blade, but this blade did do a fine job.
As for Ryobi tools, I really have mixed feelings about them. They have good and bad products. The BT tablesaws are standout as far as design and cost go. It's a bunch of saw for $299. High precision that you do not find with many of the lower end tablesaws. I am on my second one, because my Father in Law had to have mine after he seen what it is capable of.
Anyway, I have had to return a couple of Ryobi tools. They simply were not up to par. Bad designs. This was a biscuit joiner and a 16" scroll saw. The other Ryobi tool that I do own is the 9" bandsaw. BS901.
It is small, but don't let its size fool ya. It is a little work horse. It cuts any grade aluminum that I have tried. Bimetal blade, of course. So.....two absolutely great tools and two returns. About a 50-50 shot as to it being a keeper.
No more progress on the router yet. Sometime soon, with a little luck.

[xairflyer]

6061 and 6082-T6 machine very well, and are the standard used in most aircraft that I work on in my day job. Very good quality ally.
6063 is great for tube easy bent and won't snap/break when bent like 6082 but is a bit soft for machining.

[LeeWay]

Here is a question. This one should be simple. After contemplating over and over about the lead screws, I decided to order ball screws for the remaining y and z axes. I chose 5/8" screws with a 13/64" screw lead. Now my x axis is 5/8 8 thread. These are similar in rotational distance, I think. How would I allow for the differences of the screws on a particular axis? Is this something I might set in Mach 2?

Next question. I ordered these ball screws from Mcmaster Carr. Why was this particular size so much cheaper than all the rest? Is this just a larger used size?
Catalog page 960. Part number 5966K26 and the ball nut is 5966K16.
Thanks in advance for a little enlightenment.

[ger21]

Originally Posted by LeeWay Here is a question. This one should be simple. After contemplating over and over about the lead screws, I decided to order ball screws for the remaining y and z axes. I chose 5/8" screws with a 13/64" screw lead. Now my x axis is 5/8 8 thread. These are similar in rotational distance, I think. How would I allow for the differences of the screws on a particular axis? Is this something I might set in Mach 2?

Yes, just set it in the software. Each axis can use different screws, if you like.

Originally Posted by LeeWay Why was this particular size so much cheaper than all the rest? Is this just a larger used size?

Yes again.

[LeeWay]

Thanks. I went ahead and ordered the other ball screw and nut from Mcmaster Carr for my x axis. These look to be nice units for the price. I might as well make them all three the same since its much more efficient. I was worried about the wear on the brass nuts anyway. They may have worked well, but I wouldn't want to have to switch this all out later if there was a problem.

Now these ball screws and nuts are made by Thompson. They come seperately of course. Are there any particulars to watch out for when installing the nut on the screw? I sure don't want to drop the ball(s).
They have a cardboard tube holding the balls in place now. Do I simply and extremely cautiously thread one in while pushing the tube out the other side with the screw?
Thanks in advance.

[buscht]

Lee, here is what I have done.

Note: The balls will fall out if you aren't careful!

I had the ends of my ball screws turned down for bearings and coupler attachments. This diameter fit perfectly inside the cardboard tube that came with the nut.
I cut the plastic tie and carefully placed the tube and nut over the end of the ballscrew.

I held the assembly vertical and the nut more or less just threaded itself onto the screw. The tube just pushed right out the top.

Hold your hand on the screw below the nut so it doesn't spin down and fall off the bottom.

It's very easy.
Trent

[LeeWay]

Thanks Trent. That sounds about like how I imagined it should go. Confirmation is appreciated. You mean the weight of the nut will spin down the ball screw without having to turn it by hand?
Well, that is efficient.

[LeeWay]

Well, just another small update.
I now have the machine back to where it was before I ordered the ball screws. I have the ball screw milled for the x axis. Man! That is some tough steel. It was all my little mini lathe could do to get it milled down right. I did use carbide cutters, but I think this was actually more than what is recommended to be cutting with a ML. Only four more turnings in hardened rod, though. It will handle that.
What I had to do was to adjust everything tighter than normal to keep the carriage from moving out of the way instead of cutting.
I had anothet ML that I sold to my Father in Law. I had that one tuned already, but never really did much to this one. I can see that I will have to work on it some. Just a little too lucy goosy. I normally just cut brass with it, so I hadn't seen a problem with that.

I have also decided to make my Y axis similar to the X. Two tracks. You see one in the photo's above. I am making an identical one for the front of the gantry.
I think this might yeild the best results. I will be using a PC 690 router in the Z. There seems to be enough roon for everything. I have some small THK rails for the Z axis.
The only diffeence other than the distance apart between the X and Y will be that the ball screw will be on one side only. That hopefully shouldn't present a problem.
Does anyone foresee any problem with my Z axis ball screw and motor being in the center between the two Y tracks? Off to one side if looking straight on from the long end of the X. Most of the ones I have looked at are behind the router near the Y lead screw.
If I get a chance, I will draw up a little something to help visualize my intent.
Thanks for looking Guys.
Hopefully have another update soon.

[LeeWay]

Here are a couple of photo's of the build so far. These show some progress with the front rail and the trollies for the Y axis. The router will of course, be inside these rails and the Z axis movement will be on the right side as you look at it in these pics.

One drawback I see is that access to bit changing won't be a easy. Doable certainly, but not optimal. I think that the rigidity of the Y will be worth the trade off though. Since the machine is so small, it is easy enough to reach it from any side.

I will have to add two plates. One on either side of the Gantry to catch the lead screw for the Y axis. There simply wasn't room between the rails for both the Z and the Y drive line.
I am using 3/4" aluminum plate for the base of the Z and it will have an ear at the top rear of this plate that will catch the ball nut.

I used adjustable Delrin pads under the rails for the X axis. This seems to be a good soloution to keep it from lifting so far. I will use this same technique on the Y axis trolly.

From the looks of the way everything is working out so far, I should see about a 22" by 36" capability with the Cutty Shark 1.
Thanks for looking and thoughts, warnings and comments are always welcome.

[xairflyer]

Is there anyway you could make a sort of quick release clamp so you could remove the whole router when changing bits.

[LeeWay]

Well Duh! Heck yes I can.
Thats how I have used it since I bought it. Its upside down in my router table and it mounts with a quick rel;ease. Thanks for the idea. I might have hit on it myself later on, but you most likely saved me a lot of work.

I almost decided to raise the gantry some as well as widen it. I would only have had to replace the two sides, but there was a whole bunch of precision drilling and tapping that went into those already.

There is always the Cutty Shark 2.
Thanks again for the idea.