Gib Adjustment

[wwendorf]

Hi Keen,

From what you are describing, I still think you are onto the problem.

Especially with the differences in backlash on each side of the table. I know for a fact that doing minute gib adjustments isn't going to fix it. I spent 20 hours this past weekend trying every combination of how to adjust gibs that I could, and it did nothing. What is the procedure for adjusting the slideway stuff? How do you remove a gib? What do you look for to "cleanup" a gib?

Wade

I just did that test on my machine last week and with 0.005" Y backlash there was about two thou as described above - I think it is just that I am not communicating the test to you well enough. It is tricky to describe, easier to show.

Your earlier tests do indicate the issue is Y slideway racking, but the above does not. Try RJ's suggestion and just nip the gib screws and see if that helps.

Keen

[wwendorf]

I also reread your test, and I'm guessing I probably don't quite understand the setup for it.

I'd be happy to redo the test. Is there anyway you could post a pic of where and how you want the indicator, and what I should push and pull on?

Not trying to be a pain, just am not quite understanding. You know, pictures worth 1000 words and all that.

I really do appreciate the help tho.

Wade

[CountrySmith]

To remove the gib, you can use the "loosening" screw to push it out enough to grab or I find that it will slide out with the table when the "tightening" screw is removed by moving the table in that direction.

[wwendorf]

I figured that, but my problem is that I don't know what to DO with it after I get it out.



Wade

To remove the gib, you can use the "loosening" screw to push it out enough to grab or I find that it will slide out with the table when the "tightening" screw is removed by moving the table in that direction.

[wwendorf]

I have given up. I need a working machine and screwing with it night after night is just getting me mad and costing me money.

I'm sending it into a company that does machine rebuilding this week to have it tweaked out. They are going to disassemble the entire thing, redo the ways, gibs, dovetails, whatever. Full re-alignment, etc... and warranty on their work. They are guaranteeing that when they are done, I'll have .0001" accuracy.

I'm also having the Tormach ball screws re-manufactured and adjusted by another company. They are going to adjust them so I have at least the same tolerance as mill will have.

I was actually looking at maybe purchasing a Haas Toolroom mill, but that's way too much of a payment for me right now.

I don't have the equipment, time, or knowledge to tweak my mill out myself.

Time for the professionals. It's a lot cheaper to have this done than to buy a new Haas.

I really appreciate all the help you guys have given me, and I'll let you know the results of my rebuild.

Cheers!
Wade

[SCzEngrgGroup]

I have given up. I need a working machine and screwing with it night after night is just getting me mad and costing me money.

I'm sending it into a company that does machine rebuilding this week to have it tweaked out. They are going to disassemble the entire thing, redo the ways, gibs, dovetails, whatever. Full re-alignment, etc... and warranty on their work. They are guaranteeing that when they are done, I'll have .0001" accuracy.

I'm also having the Tormach ball screws re-manufactured and adjusted by another company. They are going to adjust them so I have at least the same tolerance as mill will have.

I was actually looking at maybe purchasing a Haas Toolroom mill, but that's way too much of a payment for me right now.

I don't have the equipment, time, or knowledge to tweak my mill out myself.

Time for the professionals. It's a lot cheaper to have this done than to buy a new Haas.

I really appreciate all the help you guys have given me, and I'll let you know the results of my rebuild.

Cheers!
Wade

How do you get 0.0001" accuracy using ballscrews that are probably +/-0.0005"/foot?? And with open-loop drives, and no thermal compensation, and .... That is an absolutely ridiculous claim for them to make, which would make me seriously question their honesty.

Regards,
Ray L.

[wwendorf]

I guess I'm not surprised to hear you comment back like this Ray. As stated, The ball screws are being remanufactured as well. I have a 1981 lathe that holds between .0001-0002 just fine with steppers. No reason I can't get my machine tweaked to do the same or at least a hell of a lot better than it is now.

We'll just have too see what I get. Regardless, it's going to be a lot better than tormachs stated tolerances and I'll take it. Also I left out a word in my previous post. I left out the word close, it should have said "close" to .0001 accuracy.

Wade

[wwendorf]

keen, I've tried that.

[flick]

wwendorf, I'm sorry for all your frustration. I also found the Tormach to be difficult to adjust for really excellent accuracy until I remove the gibs and scraped them true. My MRR's and accuracy improved massively once that was done - but it was a 100 hour project for me, as it was the first time I had attempted scraping. If you are sending the job to another shop, see if they can get acceptable results just by truing the gibs. It may not be necessary to mess with the ways.

[wwendorf]

I will pass that on flick. Thank u for the suggestion.

Wade

[David Bord]

Wade,

Can you give us an idea on what the two different processes cost to have done?

David

[wwendorf]

Hi David, yes I can. The complete rework of the mill will be about 3K, and the redo of the ball screws is about 2k.

I know it sounds like a lot to stick and a machine like the Tormach, but if I can get the accuracy that I want for that little investment I will do it. My machine suits my needs perfectly except for the problems I'm having keeping accuracy and with the backlash issues.

Wade

Wade,

Can you give us an idea on what the two different processes cost to have done?

David

[wwendorf]

Hi Wade - Sounds like you are committed now ...so no point in arguing with you.

Please keep us posted with all the details - this is a very interesting development.

Wish you all the best.

Keen

Hi keen, I am not trying to come off like I am arguing. I just need to get my machine working. I have been down with this issue for almost 2 months now. I need to get my machine up and running. I can't sell any more of my stuff if I can't make parts. I could try taking out the Gibbs and scraping them myself, and then I could also royally screw them up. I don't want to do that. I did find out from Tormach that Gibbs Armachine specific and they do not sell replacements. I am at the point where I want a professional to fix my machine the way it needs to be. I would be happy if I could find someone who would work on the Tormach, but that does not seem to be.

Wade

[CountrySmith]

I have given up. I need a working machine and screwing with it night after night is just getting me mad and costing me money.

I'm sending it into a company that does machine rebuilding this week to have it tweaked out. They are going to disassemble the entire thing, redo the ways, gibs, dovetails, whatever. Full re-alignment, etc... and warranty on their work. They are guaranteeing that when they are done, I'll have .0001" accuracy.

I'm also having the Tormach ball screws re-manufactured and adjusted by another company. They are going to adjust them so I have at least the same tolerance as mill will have.

I was actually looking at maybe purchasing a Haas Toolroom mill, but that's way too much of a payment for me right now.

I don't have the equipment, time, or knowledge to tweak my mill out myself.

Time for the professionals. It's a lot cheaper to have this done than to buy a new Haas.

I really appreciate all the help you guys have given me, and I'll let you know the results of my rebuild.

Cheers!
Wade

Wade, Good luck with your endeavor!

Tormach had led me to believe that .0015" accuracy was the best that could be hoped for on a small machine. I accepted this for some time but, on another forum, saw that people were getting sub thousandths accuracy on similar sized machines. That is why I started playing around with my 770, trying to improve it. I have made some progress but it is still not the machine that I think it should be.

Please keep us updated on your progress!

Bob

[wwendorf]

Bob, I will do that. I'm not sure there will be a whole lot of status stuff, but I will be sure to do a writeup when I get my machine back in a week or two. My lathe I mentioned earlier is a Southbend Magnaturn, and it is from 1981, and weighs in at 400 lbs. If that can maintain .0001" accuracy, there's no reason a Tormach shouldn't be able to. Besides the difference of US vs Chinese manufacturing of course.

Wade

Wade, Good luck with your endeavor!

Tormach had led me to believe that .0015" accuracy was the best that could be hoped for on a small machine. I accepted this for some time but, on another forum, saw that people were getting sub thousandths accuracy on similar sized machines. That is why I started playing around with my 770, trying to improve it. I have made some progress but it is still not the machine that I think it should be.

Please keep us updated on your progress!

Bob

[CadRhino]

My new 1640 Taiwanese lathe can hold .0001 accuracy but it is not moving in 3 axis while cutting like my tormach 1100 is.

Bob, I will do that. I'm not sure there will be a whole lot of status stuff, but I will be sure to do a writeup when I get my machine back in a week or two. My lathe I mentioned earlier is a Southbend Magnaturn, and it is from 1981, and weighs in at 400 lbs. If that can maintain .0001" accuracy, there's no reason a Tormach shouldn't be able to. Besides the difference of US vs Chinese manufacturing of course.

Wade

[wwendorf]

I hear what you are saying, but i'm not even talking about with a tool spinning. I'm talking about when it is just being tested with a dail indicator. The best I can get is .0015 to .0018" on Y. X varies as well. Z isn't too bad, but I have some fairbacklast there too. From everything I have learned from Keen and others in this thread, I'm fairly confident there is a problem with the gibbs. I don't know enough about machine rebuilding to understand the repair process, so I'm paying professionals to do it.

My new 1640 Taiwanese lathe can hold .0001 accuracy but it is not moving in 3 axis while cutting like my tormach 1100 is.

[CadRhino]

If I were in your shoes I would hire a professional machine rebuilder too. Good luck.

I hear what you are saying, but i'm not even talking about with a tool spinning. I'm talking about when it is just being tested with a dail indicator. The best I can get is .0015 to .0018" on Y. X varies as well. Z isn't too bad, but I have some fairbacklast there too. From everything I have learned from Keen and others in this thread, I'm fairly confident there is a problem with the gibbs. I don't know enough about machine rebuilding to understand the repair process, so I'm paying professionals to do it.

[TurboStep]

They are guaranteeing that when they are done, I'll have .0001" accuracy.

I left out the word close, it should have said "close" to .0001 accuracy.

They are "guaranteeing" that it will have an "accuracy" "close" to .0001? How EXACTLY are you/they defining accuracy? Are you sure you're not confusing accuracy with repeatability?

The complete rework of the mill will be about 3K, and the redo of the ball screws is about 2k.

If I were to give out 5K I'd want to be very sure both parties understood and agreed on the expectations - not just the price.

The ball screws are being remanufactured as well.

How do know the ball screws need to be "remanufactured" (Uhh - what does that actually mean?). For reference, a new Y-Axis ballscrew and nut can be found here for $522.59:
30448 - Y Axis Ball Screw and Nut for PCNC 1100.

Step

[wwendorf]

They are "guaranteeing" that it will have an "accuracy" "close" to .0001? How EXACTLY are you/they defining accuracy? Are you sure you're not confusing accuracy with repeatability?

Yep

If I were to give out 5K I'd want to be very sure both parties understood and agreed on the expectations - not just the price.

They know why my expectations are and are saying they can exceed them.

How do know the ball screws need to be "remanufactured" (Uhh - what does that actually mean?). For reference, a new Y-Axis ballscrew and nut can be found here for $522.59:
30448 - Y Axis Ball Screw and Nut for PCNC 1100.Step

They are going to make sure they are as true as possible, adjust the preload, and install larger balls if necessary to get movement as good as possible within the capabilities of the steppers.