Gib Adjustment

[kstrauss]

Checking a part for roundness sounds trivial but is actually difficult. Other than rotating the part about its exact centre with an accurate spindle and sensing the periphery with a probe of some sort, I believe that any other method can be fooled by various types of lobing. If you are interested in such arcane topics you may want to find a copy of Foundations of Mechanical Accuracy by W.R. Moore (that is the Moore of jig borer fame). The book devotes almost 10% of its 350 pages to defining roundness and suggesting ways to measure it.

See for an example of how misleading simply measuring with a micrometer can be. There are other shapes that are equally confusing to V-anvil micrometers and other fancy instruments. This type of possible error is particularly important when measuring things that are frequently lobed such as interpolated circles.

[twocik]

Wade, It takes time, lots of time. I suggest taking out the gibs "very carefully" to inspect and clean. I found all kinds of casting debris and rough edges that made my machine stall at certain points. I lightly sanded and deburred them, oiled them back up and was able to reduce all of the above. I'd also check all bolts, nuts that you can. My ballscrew housing bolts were loose in Y and X, made a big difference. If you're shimming your machine, look out for twisting. I was chasing my tail for days because of a shim. Hope that helps, feel free to fire away.

[wwendorf]

WAY past that now. I got upset and took my mill in and had it professionally rebuilt.

Cost me a chunk of money, but the machine is nice and tight now.

Wade

[RedneckPhysics]

Wade, It takes time, lots of time. I suggest taking out the gibs "very carefully" to inspect and clean. I found all kinds of casting debris and rough edges that made my machine stall at certain points. I lightly sanded and deburred them, oiled them back up and was able to reduce all of the above. I'd also check all bolts, nuts that you can. My ballscrew housing bolts were loose in Y and X, made a big difference. If you're shimming your machine, look out for twisting. I was chasing my tail for days because of a shim. Hope that helps, feel free to fire away.

Sorry to hijack this thread, but you described a situation I think I'm going through twocik. Gib adjustments aren't behaving as expected, and I've seen some very conspicuous scarring pop up after adjustments (probably not more than a few um, but very visible) on the way flats and dovetails.
I also wonder if this could be related to debris caught in the way oil cutouts/passageways, because it looks like there's scarring happening right where these are located on the Z-axis way, opposite of the gib.
How exactly did you go about removing your gibs without causing any damage in the process?

Thanks,

Mike

[wwendorf]

I actually didn't. I had a company near me do a rebuild on the ways and gibs of my machine.

I can't give you the specifics of removing them, because I don't completely remember, but I believe you just pull that front adjustment screw completely off.... remove the back one, and the gib slid out of the front (on the Y axis).

I never saw the X removed, but I believe it is the same process.

I used Precision Machine Rebuilding, Inc. for the rebuild.

Wade

[mountaindew]

I actually didn't. I had a company near me do a rebuild on the ways and gibs of my machine.

I can't give you the specifics of removing them, because I don't completely remember, but I believe you just pull that front adjustment screw completely off.... remove the back one, and the gib slid out of the front (on the Y axis).

I never saw the X removed, but I believe it is the same process.

I used Precision Machine Rebuilding, Inc. for the rebuild.

Wade

Hi Wade. About how much did this enhance the performance of the machine? Never read about what they did and the original Tormach spec and what you see now. My Tormach makes decent precision parts. I find it makes way better parts the more I use the machine and the better skills and tooling I use to cut them In other words experience and sharp tools help and higher quality machine tolerances improves this more.
Some day like keen and other tormach owners have done. I would like to rebuild my machine. Clean ,inspect and carefully assemble the machine not so much to improve performance but to keep it in top shape for many more years of use.


RedneckPhysics
If you want to know just about how anything works or how to make, take apart, and or destroy it. YOUTUBE is the place to find it.

[wwendorf]

Well, I'd say QUITE a bit. Tormach's official tolerance is about .0013" and I'm now at .0005".

Also, if I machine out a 1" x 1" square, I am now getting EXACTLY 1.000" x 1.000" in 6061 aluminum.

My tolerances were out to about .0028" and I wasn't able to tighten them up at all. Keep in mind this was on a 4 year old machine with heavy use.

Wade

[mountaindew]

Well, I'd say QUITE a bit. Tormach's official tolerance is about .0013" and I'm now at .0005".

Also, if I machine out a 1" x 1" square, I am now getting EXACTLY 1.000" x 1.000" in 6061 aluminum.

My tolerances were out to about .0028" and I wasn't able to tighten them up at all. Keep in mind this was on a 4 year old machine with heavy use.

Wade

Nice
I like the fact that anything can be improved with skill and process. I dont have the tools, skills or process to improve my tormach, nice to know it can be done! hint "youtubers!"
Instant subscribe and follow along! of a complete tear down and assemble with all the proper tools to do it.

[wwendorf]

I didn't have the skill for doing the gibs either, or the knowledge or understanding of the process. I had a professional machine tool rebuilder do the work for me.

Cost me some money, but I didn't screw my mill up either.

Wade

[smorell]

I actually didn't. I had a company near me do a rebuild on the ways and gibs of my machine.

I can't give you the specifics of removing them, because I don't completely remember, but I believe you just pull that front adjustment screw completely off.... remove the back one, and the gib slid out of the front (on the Y axis).

I never saw the X removed, but I believe it is the same process.

I used Precision Machine Rebuilding, Inc. for the rebuild.

Wade

Good to know, they aren't too far out from me. I'm in St. Paul,MN