[bhurts]

In order to preserve room with a vise I made a modular set of jaws. The vise is two pcs and the moving jaw only has 1" of travel. They are attached to the table with 4 tapped holes in the table top per jaw. That way I can make the opening 1/4 inch or 18 inches as needed.

Ben

[nateman_doo]

Sounds interesting... Can you post a picture of it?

[nateman_doo]

Nate, I don't see why you need the gears to fit under the table really. You can still get max travel from a screw without the belt ever going under the table. Placing the nut on the outside of the table will still allow a screw shorter than the rails to gain max rail travel. Traditionally speaking. If you are going for an oversize table, then I can see the need.

I just stared at the table for a while yesterday, and I think I may be able to make the gears larger, but it depends on how far out the ballscrews can stick out over the edge... and if they will fit under the bellows. What I have right now "works", so I will stick with that until I get all the components. Its easy enough to change a pulley.

[nateman_doo]

Z rails arrived. You guys want to see the size difference between 35mm rails, and 25mm rails??







CRAZY right??!

[nateman_doo]

In order to preserve room with a vise I made a modular set of jaws. The vise is two pcs and the moving jaw only has 1" of travel. They are attached to the table with 4 tapped holes in the table top per jaw. That way I can make the opening 1/4 inch or 18 inches as needed.

Ben

Im not letting you off the hook on this one. I can see something in my head, but its blurry. take a picture already!!?
I see a long bar that gets pinned/bolted to a tool plate as the "fixed jaw", but the moving jaw im trying to picture in my head... thats the blurry image. Sort of looks like the holding apparatus that my chop saw uses.

[LeeWay]

Grizzly.com

I have one of these.
It's pretty cool.
It's as precise as you set it up.

[nateman_doo]

OMG?! get out of my head?!?
AHH!!


thats exactly what I pictured! Not as fancy, but yes!

[bhurts]

Ill take a few pictures and download them when I get home. My vise is the same idea as the one shown but its a bit more low profile. Its a pretty simple design but very effective for what I do. It is made from 2 pcs of 1.75x1 inch and 1pc of 1x1 aluminum tooling plate. All are 5.75 inches long. Also 3 Bearing bronze bushings, 2 -1/2x3" ground pins and a pc of
1/2-13 acme rod. The center bushing is tapped for the 1/2-13 acme and the outside two are bored 1/2 inch to match the pins. It will make more sense when I post a few pics.

Ben

[nateman_doo]

how do u address the stock lifting up? Do u just beat it down as your clamping? My vise doesn't have that angle lock, so I have to beat mine down.

[LeeWay]

The one time I used mine, I used parallels.
I did not seem to have a lifting issue. The parallels stayed tight.
I imagine a thin shim placed under either side would angle it even more so the parts would slip downward. These aren't like regular vises that run on ways.
I imagine too, that it has a lot to do with how well the vise is actually machined. Mine has seen very little use in the scheme of things, so your mileage may vary.

[Fastest1]

I have always thought these 2 piece vises would be nice.

[nateman_doo]

As I was bolting the 80/20 under the lowermost plate I decided to check the accuracy of the rails again.


I was rocking the bearing back and forth and I found some decent slop in them. How does one go about fixing this? Can you just put oversized bearings in them, or is this normal? I bought them used from e-bay, so i guess you get what you pay for.

[Spk64]

Looks like the movement is from twisting the car magnified by 12-14"?
Once you have 4 cars mounted on slide I would check the amount of play. My guess is you will not see any side to side or up and down.


Steve

[crazydiamond]

Are the balls caged or contained in the block? The previous owner could have puuled the bearing off the rail and lost a few balls. It's a bit tricky to add more balls (some manufacturers afternate the sizes of balls to create bearing preload) but I'm guessing the block is missing some

Sent from my HTC One using Tapatalk

[nateman_doo]

The balls are very easy to remove. I measured them individually:




Im on Mcmaster, and I found 5mm balls, but I am looking for something smaller. I would agree the play will likely be reduced when I put it all together, but I am guessing there is a reason these rails were on e-bay. Do they fall out of tolerance and they are replaced from working machines then sold and in my hands? Figured balls just a breath wider might help with the slop. If I can find something just barely oversized, I could experiment before I put it all back together and get lazy.

3/16 balls are 0.1875, so that would be 0.00015" oversized. Anyone else have a suggestion?

[nateman_doo]

So does anything think those bearings actually ARE 3/16" bearings and thats what they would actually measure? Its a $7.00 investment to try out a box of 50. That may do one block, so i would need 8 boxes or less if that works.

In other news, here is the stepper vs the servo:

Im very excited to try them out, but that will be a while still.

[LeeWay]

Whatever brand they are, you should be able to look them up and see what size they are. That or contact the maker.
Otherwise I would think that 3/16" might be the closest. I have seen worn balls in some of my THK rails. They get more football shaped when they start to wear. Mic the balls around the circumference and see if it changes. Mine were not that obvious in appearance, but I could actually tell rolling them between my fingers. No, I don't need no stinkin micrometer.

[nateman_doo]

I looked at every pdf I could find on NSK LH 25 guides. WHOLE lot of technobabble, but no actual ball bearing size listed. They probably don't want you experiment. In any case, the 5mm ones are 0.00955" oversized vs the 3/16 being 0.00015 oversized. The manual also says to use 2 blocks bolted to check the rail. The only problem with that, is I loose some of the range to check the length of a single swipe, but I guess I could just continuously re-position the indicator.

[LeeWay]

I did find the info on one of the websites at some point. It was buried pretty deep IIRC. Maybe they were THK.
I would just try to redo one truck if I was going to attempt it. They are not that hard to do. If your balls are not actually worn and there is just a little play like you showed, then maybe alternating new and used balls would get you a tighter tolerance.

I ordered a really tiny set of THK rails early on off Ebay that had the football bearings in them. They were too small for my needs and cost me about $20. I always thought I would put some round balls back in them and REbay them again. Just too much to do and too little time.

[nateman_doo]

Why alternate, and just replace them all? I feel like I remember reading alternating balls in the ballnuts, but I don't understand the point of alternating aside from less contact area is less wear. I thought the idea was more contact area for less play.

My choices in ball bearings are:
Bearing-Quality E52100 Alloy Steel (+/- 0.0001) 100 for $3.22
Tight Tolerance (+/- 0.00005") 5 for $5.94 (too expensive)
Hardened Shock-Resistant S2 Tool Steel (+/- 0.001") 100 for $3.03 (looser tolerance)
Bearing Quality High-Temp M50 Tool Steel (+/- 0.00005") 5 for $7.76 (too expensive)

So I guess the Alloy Steel has the tighter tolerance for only $0.19 per hundred. Sort of a no-brainer. 400 balls for $12.88 I am sure that will be MORE then enough. Will probably have some extra in case I need to tear down the Tormach build and replace some in there too since they use the same rail system.