[ger21]

What do you use to adjust and tension your rails?
Thanks.

There is no adjustment. Only on one end of one rail, because I needed a litttle bit of room to be able to get the rails through the end plates, as it's a very tight fit. The gantry and base torsion box ribs hold the pipes in place, and each is perfectly flat. (As flat as my 4 ft level, at least). There are threaded rods under the table holding the gantry sides tight to the rails.

[Pat2000]

This is a big concern for me. When the thing is finally running, I'm going to see if I can make some delrin covers that hold a felt wiper over the bearings. We have a large saw at work that uses a system like this. The felt is saturated with oil, which gives you an oiled surface for the bearings to ride on, while wiping the dust out of the way.

Thanks, I see, bit of a difficult kinda shape to cover ! hope that goes Ok

[ger21]

I'm working on my Z-axis, which need some additional panels attached to keep if from flexing (design flaw ). The problem is, there is very little extra room to mount the panels, but I think I have it figured out. I only have room for 1/4" plywood, which is kinda flimsy, so I'm laminating some aluminum skins (.025) on to the 1/4" with epoxy. I'm going to throw them into my vacuum press shortly, so they'll be ready to cut and mount tomorrow.

In the meantime, I made a jig to turn the ends of my acme down with a router table. I bought some 1/2" ID bearings from Mcmaster Carr, as well as some 1/4" shank grinding stones. I set my router to 10,000 rpm, clamped the jig to the router fence, and fed it into the stone while turning it by hand. I'm using rollerblade bearings, so I need an 8mm shaft. I soon realised that grinding the 1/2" down to 8mm would take a loooong time, and if I got to aggressive, the screw got very hot. So, I pulled out the screw, and using my 12" disk sander, sanded all the threads off in about 1 minute. Then back to the grinding jig for basically a finishing pass.

Now, this is not an extremely precise setup, as fine tuning the fence turned out to be a bit tricky. Because of the lack of high precision, I had to end up a little on the small side, but I was able to get a very good fit. The ground area is within .001 it's entire length, .312-.313. 8mm is .3149, so I'm within .002-.003. And the tranition into the threads is radiused, so the bearing self centers. I then used an 8mm die to thread the end, and mount a nylon lock nut. The bearing will mount to the bottom of the screw, with the outer bearing in a 22mm counterbore under a 1/4" aluminum plate, and the top bearing resting on top of the plate. Here's a few pics.

[joecnc2006]

Very inovative, you did an excelent job with what you had, now that something i would do

Joe

[Weldtutor]

Ger
Very innovative solution to turning down the end of the acme threaded shaft. Thanks for the explanation & great photos.
I've been wrestling with a similar problem recently & this certainly helps.
Perhaps you could post a photo of the end of the shaft assembly as you explained.
Thanks, WT

[ger21]

Sorry if these are a little blurry.

[Weldtutor]

Ger
Your bearing mounting technique should do the job quite well!
Thanks for the fast response.
WT

[ger21]

The X and Y axis will use the blocks I've shown earlier in this thread, Just the Z- is like that. All the screws will be done the same way.

[phantomcow2]

Your router is very impressive. Some great ideas here, very innovative indeed.
Have you thought about buying a mini-lathe? They are reasonably priced, and are perfect for things like turning down shafts of leadscrews. I would not have been able to do half of my projects without it, including parts for my own router.

[ger21]

My wife would kill me if I bought a lathe. I don't like to buy cheap tools, so I'd probably end up spending a lot of money on one. I'll probably get one someday, but not in the immediate future.

[phantomcow2]

Yea these little lathes do have their limitations. I would have saved up for a large one, but I have access to a 13x48 Clausing everyday. So for anything large, i just use that.
FOr hte price though, it cant be beat!

[ger21]

Got a little more done.

[santiniuk]

That's one stylish looking machine. Great workmanship !

[spalm]

Dang Gerry, you do good work!

Did those side plates on the Y carraige help? I'm guessing: yes.

What kind of motor couplers are you going with?

(BTW, my wife has killed me several times, really doesn't hurt that much after a while )

Steve

[phantomcow2]

Nice Z axis!

[joecnc2006]

Very nice work indeed, keep the pictures comming

Thanks, Joe

[2muchstuff]

I liked how you wrapped the z carriage around.

[DDM]

Have you noticed any skewing side to side on the gantry, I could see on some of the wider machines having problems if the bearings ride on only one side of the pipe so you only have a total of 8 contact points in 3D. It's something that I've been fighting in my design process. Best of luck the machine looks great.

[Pat2000]

Niiiice !! going to follow with interest - I've just m/c'd a Beam/plate for my m/c that will use two 20mm silver steel dia bars top n bottom, I'll have channel section on the back of a 10mm 1.3m long ally plate, still undecided about bearings tho.

Like it. keep posting

Pat

[Pat2000]

Have you noticed any skewing side to side on the gantry, I could see on some of the wider machines having problems if the bearings ride on only one side of the pipe so you only have a total of 8 contact points in 3D. It's something that I've been fighting in my design process. Best of luck the machine looks great.

use two drive screws instead of one (Ok I'm talking Acme ones) - end of prob, at a price!