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Back GearAdjustment

Kevin T

Stainless
Joined
Jan 26, 2019
Back Gear Adjustment

I have been trying to tackle the very noisy back gear on my machine. It's such a violent noise at cone position 1 or 2 (small end) that I basically just don't use those, but that bothers me. I set aside some time today to mess with it and I can make it really quiet compared to how noisy it has been up to now but....only if I have it adjusted real tight to engage. Makes me want to ask how much force does it take you guys to pull that back gear up into position? I had it adjusted "light" just so it didn't pop out of engagement and wasn't satisfied at all.
 
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If I'm reading you right, you adjusted down or tighter on the bushing for internal shaft of back gear. So that the effort to move handle is more stiff.

If that is correct, I dont have a problem with it. But mine is not personally tight, It moves kind of nice. A little resistance, but not too heavy at all.

What I would be interested in also, is the gear lash on both gears on back shaft to both gears on spindle. If your gear lash is excessive, it will be noisy. And if the gear lash is zero, thats bad, and maybe noisy.

I do believe there is a way to adjust that gear lash, but knock on wood :D, I have not had to it. Not sure if the bushings for back gear are drilled off center, so rolling bushing might change lash. Or perhaps stops on the back gear for engage/disengage. Not sure, I'd need to look at it closer, and research a little.
 
My "farmer" way of setting gears, at least 16DP and up, is to take a piece of copy paper, which is about 3.5 thou thick, set it between the gears and adjust till it is hard on the paper. Remove paper by rotating gears, I've got about 3 thou clearance.
 
If I'm reading you right, you adjusted down or tighter on the bushing for internal shaft of back gear. So that the effort to move handle is more stiff.

If that is correct, I dont have a problem with it. But mine is not personally tight, It moves kind of nice. A little resistance, but not too heavy at all.

Yes this is right.

My "farmer" way of setting gears, at least 16DP and up, is to take a piece of copy paper, which is about 3.5 thou thick, set it between the gears and adjust till it is hard on the paper. Remove paper by rotating gears, I've got about 3 thou clearance.

I tried to mess around with the gear engagement depth but couldn't tell if I had it right. The noise comes from the spindle end of the back gear. I think you guys both tried to help me before on this and I need to go through setting the gears again it would seem. If for nothing else but peace of mind, but I noticed that tightening the lever rotation made a big difference in the noise so I wanted to ask about that. Thanks
 
Normally one face of a gear tooth contacts another one face of a gear tooth of opposing gear, during normal gear rotation.

But if you have one of a few problems, one gear tooth may contact on both faces of its tooth, as it sort of bounces back and forth, between two teeth of opposing gear.

From your description, it sounds like this. And my guess is by tightening engagement handle, you have reduced the ricochet of bouncing. I would say no doubt an improvement, but my guess is the underlying problem of why is not solved.

Maybe gear lash, or alignment (though doubtful here, as both shafts are held by bearings on both ends). Or maybe excessive bushing/bearing wear on something, like cone pulley bearing, a back gear bearing, spindle bearing etc.

Besides Rudd's trick for setting clearance, you can also check what the actual number is, prior to a change. If you can finagle a dial indicator so pointer reacts off a gear tooth, or a small clamp near outer diameter of a gear and react off clamp. . . Hold one gear/shaft solid, and just lightly rotate back and forth on gear your measuring for a reading on back lash. At least get a general idea if its .001" or .1" :D

Might want to get a pry bar and lift up and down on back gear shaft, cone pulley, and spindle, might find something pop out at you.
 
OK so quick check on the backlash looks like I am about .00675. But if I crank everything down right here all seems quiet..(er).

Let me know if you see me measuring wrong please.

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Zeroed and got this.

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.006"-ish is not bad for gear lash. No doubt there is a spec somewhere, but I wouldn't call .006" excessive. North of .010" would have my attention, and .020" plus I'd need to fix.

Do you think you're .006-ish on both gears of back gears ? Might be hard to tell, if big gear is stopping first, or small gear of back gears.

Another question. When you say you adjusted engagement handle really tight. . . No gauge I know :D, but how tight would you describe it. Like two hands and a pipe to move it :D :D. Or just pretty hard with one hand ?
 
Another possibility, is you might be getting some transference from further down the line in the total gear train. A weird stress or vibration that's tranfering to those gears, though they are fine.

Like maybe leadscrew alignment, or end gears or something.

Might run some tests loaded and unloaded. Or sections engaged or disengaged. See what varies. Is saddle and crossfeed travel real smooth or ever noisy or bindy ? etc.
 
..."Another question. When you say you adjusted engagement handle really tight. . . No gauge I know :D, but how tight would you describe it. Like two hands and a pipe to move it :D :D. Or just pretty hard with one hand ?"...

As hard with one hand as any large football player on roids or a 20 year rock mason could do with one hand and a 3 1/2 inch long (vintage wrench of course) could! So pretty tight... like where a beta male or a gender confused snowflake could never undo it with two hands, but not stupid tight where special tools and spray nitrogen and mapp gas are needed! ;-) LOL

disclaimer: I always open the pickle jar on the first try! even the old crusty one with dried goo around the rim!
 
Are all your teeth clean? No, not those, your gear teeth? Your second picture above shows some white stuff in the gullets.

Dang you've got a keen eye! I have gone over and over them but yes you are seeing the remnants of a futile attempt at applying an ever so small amount of grease to the gears. It will be removed sir. I could clean up some more maybe? On the large backgear gear there are dark areas on the teeth that I have had a heck of a time with. It's almost like gunpowder residue. I stopped trying to get it all off because I thought it was too thin to matter but what do you think? Aw heck I better check that box off and clean it bare yeah? Does anyone have a recommendation for how to get that stuff off?

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I cleaned up the gears and reset the gears to .003 with the paper trick but it really didn't help too much with the noise. So I took the backgear assy out of the machine and found what is probably part of if not all of the problem.

The large gear (Quill Gear) is wobbling on the shaft!

I have a worn out quill sleeve or a worn out gear, or both :-( I pulled the large gear off the shaft by hand!

P1060731.jpg

Shows up as .010 out at the teeth. I guess that would explain some of the chatter marks on the gear teeth in the close up!

P1060735.jpg

Now what to do about it? I could probably remake the quill sleeve except for aligning up the keyways and cutting them for the gears. I am not sure I have the stuff to make that right. I could sleeve the gear too. What do you guys think? If I sleeve the gear how thick of a sleeve do you think I'd need? The other thing I could do is make a spacer to go over the end of the sleeve to help keep that gear from wobbling so easy. This is totally in my wheel house. I could press fit on a beefy shoulder maybe fashion up a thicker key to hold the gear but wanted some thoughts before I do. I guess it couldn't hurt to try that first and if my back gear operation improves dramatically I'll be good for a while. What say you?

P1060733.jpg
 
I cleaned up the gears and reset the gears to .003 with the paper trick but it really didn't help too much with the noise. So I took the backgear assy out of the machine and found what is probably part of if not all of the problem.

The large gear (Quill Gear) is wobbling on the shaft!

I have a worn out quill sleeve or a worn out gear, or both :-( I pulled the large gear off the shaft by hand!

View attachment 301570

Shows up as .010 out at the teeth. I guess that would explain some of the chatter marks on the gear teeth in the close up!

View attachment 301571

Now what to do about it? I could probably remake the quill sleeve except for aligning up the keyways and cutting them for the gears. I am not sure I have the stuff to make that right. I could sleeve the gear too. What do you guys think? If I sleeve the gear how thick of a sleeve do you think I'd need? The other thing I could do is make a spacer to go over the end of the sleeve to help keep that gear from wobbling so easy. This is totally in my wheel house. I could press fit on a beefy shoulder maybe fashion up a thicker key to hold the gear but wanted some thoughts before I do. I guess it couldn't hurt to try that fist and if my back gear operation improves dramatically I'll be good for a while. What say you?

View attachment 301572

That gear is not original...
 
You know. . .I'm looking at your pics last night, and I'm thinking something looks funny. Just couldn't put my finger on it. Even went out to peak at mine, and check travel, tension etc.

Again today, with your new pics. So I go out again. Its a good thing it wasn't a snake, I'd be dead ! :D

Someone has replaced at least the large gear on yours. Factory or not, I don't know. But style is different like its a made gear. Besides possibly not concentric, gear teeth potentially a little different would be noisy against mating spindle gear.

I might check for an original back gear. Cost might not be terrible. Could likely mate better as well.

Our machines are close in year of manufacture. One pic off my 2H, the other I happen to be going through the head stock.

103.jpg 104.jpg
 
You know. . .I'm looking at your pics last night, and I'm thinking something looks funny. Just couldn't put my finger on it. Even went out to peak at mine, and check travel, tension etc.

Again today, with your new pics. So I go out again. Its a good thing it wasn't a snake, I'd be dead ! :D

Someone has replaced at least the large gear on yours. Factory or not, I don't know. But style is different like its a made gear. Besides possibly not concentric, gear teeth potentially a little different would be noisy against mating spindle gear.

I might check for an original back gear. Cost might not be terrible. Could likely mate better as well.

Our machines are close in year of manufacture. One pic off my 2H, the other I happen to be going through the head stock.

View attachment 301574 View attachment 301573

There's a quill assy on ebay but not cheap at 275! If Ted doesn't have one I may have to go there.
 
There's a quill assy on ebay but not cheap at 275! If Ted doesn't have one I may have to go there.

I looked myself out of curiousity. Was a bit surprised by that too. It was $150 a couple of hours ago ! :D :D

Joking of course, but that higher price did surprise me. I'm sure I've seen them pop up sub $200 from time to time.
 
I got the replacement assembly today. It is much lighter than my custom quill gear! I can't wait to get it installed and hear the difference!

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