Joe's CNC Model 2006

[David Da Costa]

The only pre-load I have is the small amount using just the dumpster clamp.

[Glidergider]

Joe,
Where did you get your signfoam? A local supplier or internet source?
Dave

Originally Posted by joe2000che Here is a sign, i just cut for my daughter, ... 1st) Painted a 8"x8" signfoam Yellow then clear coat it and let dry. .... Joe

[sdantonio]

Hi Joe,

I cut a aquare today, actually it is supposed to be a square. I find that I am a little out. Attached is a diagram and was wondering which threaded rods you would suggest tightening and which you would suggest slakening.

I the square I cut distance ad is greater than bc. It seems logical to me that if I tighten up the front rods of the gantry that may pull things a little more into square. I've been trying to think whether pulling any of the table tortion box rods tighter would do anything and I can't see it in my mind. Of course, if I had thought to put in 2 running diagonally from corner to corner those would probably help a lot. That's for the next build I guess.

I might also just take one of the motorcycle tiedowns and run it corner to corner in the ad direction around the legs and pull on that.

Thanks
Steven

[sdantonio]

My nacklash problem.

I think my preload is just wat to tight. I totally removed the spring from the x axis and part of it cleared up. I'll try the y also next.

Thanks

[joecnc2006]

Originally Posted by Glidergider Joe, Where did you get your signfoam? A local supplier or internet source? Dave

they were samples from signfoam.

[joecnc2006]

Originally Posted by sdantonio My nacklash problem. I think my preload is just wat to tight. I totally removed the spring from the x axis and part of it cleared up. I'll try the y also next. Thanks

I would not think that preload would do much to backlash, the anti-backlash nut needs to be just barely tightened enough as to not allow the slight movement between threads.

As far as being square, the x-axis torsion box can be out of square and not affect the function of the machine, because its the rails that the gantry ride on, and they just need to be parrallel, and i'm sure they are.

take a large carpenters square and place it on the x-axis and draw a line on the main table, perpendicular to the rails, then jog the machine to one side and place inline with the mark, (I used a v-bit) then jog the machine to the other end of the table. and check for square, if it is out, then adjust the bolts on the side of the gantry in and out in pairs, the front two together and the rear two together, this will slightly move that side of the gantry forward or backwards, you can see it with the bit and the mark you have made, then adjust it acordingly, and repeap until you are satified, this isd also how to adjust the height from one side to the other, by adjusting the top two together and the bottom two. (you can start to get a feel of how it starts to fine tune the machine). same principle aplies to the Z-axis to make it plumb.

Joe

[sdantonio]

Thanks Joe, I'll give that a try.

I didn't mean to say that the excessive preload was causing backlash. Poor choice of words on my part. I think the excessive preload is causing the skate bearings to stick (I used regilar 1/2ID 1-18OD skate bearings on the lead screws rather than the more expensive angular contact. Under light axial loads the skates are fine. I just think Ioaded mine a little to heavy and they may be binding a bit.

[joecnc2006]

yea if you have to much of a load on the skate bearings, they will bind, lockup from lateral force, but they do work good if you snug everything up to them.

Joe

[AndrewN]

Question Joe!

I have been looking at your EDrawings of your machine and see that in the X Torsion Box you have the long braces split into 2 parts. Is there a reason for this? Is it due to the size of sheet stock you are able to buy or is this meant to be this way in the design?

I look forward to building this machine soon and will be posting pictures as soon as I start. But in the mean time I am redrawing the parts into Autocad 14.

Andrew


Edit: Right after typing this I ran across a DWG to DXF converter that can convert your DWG files to DXF or back to DWG for Autocad 14. So if you see my other post in these forums asking for the DXF files please pay it no mind as I can take care of it now. But my question above still stands. Thanks

[bp092]

Joe designed those parts to be cut in and then assembled because they are long for the machine to cut. They are easy to assemble, glue and clamp and they become very strong, especially after the torsion box is assembled. If you're cutting the parts, and can make them as one, do it. If you can't, then split stuff up like he designed. But that's why he designed those parts that way.

[sdantonio]

When I made mine I only had a manual router table and a table saw (don't get me wrong, actually I have a fully equipt violin making shop, but a 1/4 inch curved sole hand plane isn't really going to help make the router), so I made my X Torsion Box you have the long braces all 1 piece. It's a bit diffacult to hold while you cut the insets for the crosswise pipeholders, but it can be done. I suggest 2 people for this operation for safety.

Joe. I adjusted the sides and everything seens to be tracking square now. Will try a test cut sometime this week. Thanks for the suggestions. It also seems to be running smoother, but this could be my imagination.

[AndrewN]

Thanks guys, I run a cnc router at work that can make them 1 piece so I think I'll go with that. This would be more fun if I had the machinery at home to do this, but but next time it will all be done at home. Look forward to it.

Thanks again!