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12" Atlas Reverse Tumbler Gear Stud

paul s

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I bought the gear on ebay - the PN, "10-242", is cast into it. Interestingly, the bushing on the original part is loose as well - very loose. Like maybe 0.020 under.
 

RobertB

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The correct part, then must just be well worn. Should still function but may be a bit noisy and have some extra backlash.
 

wa5cab

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So both gears fit the new bushing loosely? Where did you buy the new bushing from?

What about the old bushing? Is it also a push fit in both gears?
 

paul s

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Yes, very loosely. The bushing came with the new gear off ebay - I'm assuming that's the original bushing that came with the gear. There is evidence of the new bushing having been media blasted on its OD.

The old bushing is loose as well. Both bushings measure about 1.750 to 1.751 OD, while the new gear measures 1.756 in it's bore. The ID of the new bushing is around 1.504, while the old measures about 1.502.

The old gear measures about 1.797 it it's bore.
 

wa5cab

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I don't know how well it will work on sintered bronze but I would try knurling and then install it with Locktite. You will need an expanding arbor. There used to be a cheap Chinese set on eBay pretty regularly. I think it went up to 1-1/2".
 

paul s

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Might be easier to drill and tap down in the root of one of the gear teeth for a small setscrew to retain the bushing. If needed, I could wrap some 0.001" brass shim stock around the OD of the bushing to equalize the gap.
 

RobertB

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If needed, I could wrap some 0.001" brass shim stock around the OD of the bushing to equalize the gap.
That would be the option I would choose, whatever thickness you can get a good fit with a full wrap to keep it centered. Loctite doesn't grip oilite very well unless you remove all the oil impregnated in it, but knurling like wa5cab suggested would probably be enough to let the loctite hold it

If you had a working lathe you could just make a new bushing :bang head:
 

wa5cab

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Might be easier to drill and tap down in the root of one of the gear teeth for a small setscrew to retain the bushing.
I wouldn't try that. Considering the bushing as being rigid, the set screw will push the bushing off-center. And worse, compared to the gear and the spindle, the bushing is flexible. so after pushing it slightly off center, further tightening will distort the bushing where it is under the set screw. At the very least, knurling does not have either of those disadvantages.
 

wa5cab

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... There is evidence of the new bushing having been media blasted on its OD. ...
Sintered bronze bushings often have a surface appearance similar to one that has had light media blasting, except not shiny.
 

paul s

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If you had a working lathe you could just make a new bushing :bang head:
You mean like this? But then I would have to order a chunk of bearing bronze ($$$). McMaster-Carr has bronze bushings, but the OD is 1.750 -0.000, +0.001, not much help.
I wouldn't try that. Considering the bushing as being rigid, the set screw will push the bushing off-center. And worse, compared to the gear and the spindle, the bushing is flexible. so after pushing it slightly off center, further tightening will distort the bushing where it is under the set screw. At the very least, knurling does not have either of those disadvantages.
Brass shim stock wrapped around the bushing will keep the bushing centered, and drilling the hole with the bushing installed, I could lightly drill a depression in the bushing so that the setscrew wouldn't have to be tightened down much. A little blue loctite on the setscrew, and done.

Or just shim stock and loctite - is the bushing oilite? If so, I suppose that rules out gluing it in.

P8242715.JPGP8242715.JPG
 

wa5cab

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Brass shim stock wrapped around the bushing will keep the bushing centered, and drilling the hole with the bushing installed, I could lightly drill a depression in the bushing so that the setscrew wouldn't have to be tightened down much. A little blue loctite on the setscrew, and done.

Or just shim stock and loctite - is the bushing oilite? If so, I suppose that rules out gluing it in.
Well, its your machine. But I have never had any luck with shim stock that was too thin to itself stand up to being pressed into a bore. What usually happens is that the shim stock will go just a little ways into the bore that you are pressing it into and then it stops going in with the bushing (or shaft or whatever) and just balls up around the outside of the hole. Whereas lightly knurling the OD brings its OD up enough to be a tight fit in the bore without any shim.

As to whether or not the three bushings (one in the gear and two in the pulley) are Oilite or not I don't know for certain. They don't really have to be as there is supposed to be a gap between the two bushings in the pulley into which oil from the oil hole can exit. And from there, it can run fore and aft along the spindle. The gap acts as a reservoir for a while.
 

paul s

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Finally getting back to this - I ended up using 0.001" brass shim stock in four places around the bore of the gear to keep things centered and take up some gap. Held it all together with Permatex sleeve retaining compound. It's not coming apart again, at least not without some intention.

Now I'm putting the headstock back together, and I would like the lathe to start it's new life with a fresh spindle belt.
The original is marked "S7-126". I measured it two ways: by making a mark and rolling it - 31.5"; by a string around it's OD - 32". An online search wasn't definitive - some sources say 32" (4L320), some say 31" (4L310). Opinions? Or is the tensioner range enough to cover either?
 

wa5cab

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As best I've been able to determine, it should be a 4L310. S7-126 says that it was first used on the Shaper, which came out a little before the 101.07403. The 101.07383 spindle belt is shown as L4-126. My guess is that one of them is 31" and the other 32". You could just buy one from Clausing to see. :cool:
 

paul s

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As best I've been able to determine, it should be a 4L310. S7-126 says that it was first used on the Shaper, which came out a little before the 101.07403. The 101.07383 spindle belt is shown as L4-126. My guess is that one of them is 31" and the other 32". You could just buy one from Clausing to see. :cool:
Yep - but I'd need to take out a 2nd mortgage
An A29.5 or 4L315 would give you the 31.5" that you measured. These guys (never dealt with them) https://www.vbeltguys.com/products/s7126-atlas-press-oem-equivalent-conventional-v-belt say 32" and vintage machinery says 31" http://wiki.vintagemachinery.org/Atlas-V-Belt-P-N-to-Length-Cross-Reference.ashx
Yep - lots of conflicting information out there.

I think I'll roll the dice and go with a 32" - thanks all!

In the meantime, I've been disassembling the tailstock and can't remove the quill because the quill lock is bound up. I've got the lock handle and bolt removed, but the two lock sleeves are stuck and I can't get them out of the casting. I'm guessing one needs to come out the top, the other out the bottom. I may try to tap and thread the ID on the top one and use a slide hammer or just drill it out and make a new one. Is this another case of the swelling Zamak?
 
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RobertB

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In the meantime, I've been disassembling the tailstock and can't remove the quill because the quill lock is bound up. I've got the lock handle and bolt removed, but the two lock sleeves are stuck and I can't get them out of the casting. I'm guessing one needs to come out the top, the other out the bottom. I may try to tap and thread the ID on the top one and use a slide hammer or just drill it out and make a new one. Is this another case of the swelling Zamak?
Could be swelling, but also corrosion or over aggressive tightening are possible. You can remove the crank, key, endcap and feed screw. Soak with penetrant and then with a brass punch gently tap the quill fore and aft and see if that will break them loose. Tapping the top one as you suggest could work. You could also remove the anti-rotation bolt and try and twist the quill. Heating the whole assemble a bit may also help. With the quill out both parts will come out of the top.
 

paul s

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Well, I've got the handwheel off, but the endcap is not moving. I've tried wrapping thick leather around it and using pliers, and I've tried a rounded piece of metal in the radial slots, no go. I'll attach a picture, you've no doubt seen it before; is there a special tool that engages the radiused slots? The piece of metal that I used was a somewhat sloppy fit, wondering if I need to turn something exact on the lathe? By the way, if you're wondering, I was able to turn the feed screw with a magnetic tool through the big end of the quill, to get it out of the way. I could, of course, tap on the end of the screw and try to force the quill out, but I'm not sure that's in the best interest of the feed screw threads. And after soaking in WD40, the quill lock is still stuck.

For a machine that's relatively unworn and not rusty in the least, it's just fighting me every step of the way.PB112752.JPG
 
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RobertB

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Try some heat around the endcap. Wrap some fine (like 400 grit) sand paper around the endcap, grit against the cap and grip it with some channel locks. With some heat they usually break loose pretty easy. Get something better than WD-40 for penetrating oil, like Seafoam or Kroil.
 

paul s

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I Kroiled it, didn't make a difference. Here's what I used - turned it on my South Bend, a "coin" 1.125" dia. 0.125" thick. The thickness was a perfect fit in the slots, I think the diameter could have been a little larger. Still took a fair amount of force with a large adjustable wrench. When I got it out, there were metal filings in the threads.

I was able to tap the quill out with a brass drift, still can't get the lock out. I've tapped the ID of the upper lock to 5/16-24 (it fit well enough without drilling). I can lift the entire tailstock by the tap, so I'm not optimistic as to the lock coming out peacefully, but I'll get a 5/16-24 fastener and try the slide hammer.PB112759.JPG
 

RobertB

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Now that you have the quill out you can Kroil the inside ends of the locks. You can use a 3/8" or 1/2" drive socket that is just large enough for the lock to fit in and use it as a puller base. Thread the bolt with a washer under its head through the socket into the tapped lock and tighten to pull. If the lock didn't rotate when you were tapping it, it may be quite stubborn coming out.
 

paul s

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Now that you have the quill out you can Kroil the inside ends of the locks. You can use a 3/8" or 1/2" drive socket that is just large enough for the lock to fit in and use it as a puller base. Thread the bolt with a washer under its head through the socket into the tapped lock and tighten to pull. If the lock didn't rotate when you were tapping it, it may be quite stubborn coming out.
Good idea - better and easier than the slide hammer. I'll try some Kroil, but I'm betting that I'm dealing with swollen Zamac. And no, it didn't try to rotate while being tapped.
 

wa5cab

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That is probably the best way to break the upper lock/lock sleeve/sleeve loose from the tailstock. But after 2 or 3 turns of the wrench, it will probably begin turning in the hole instead of the bolt threads continuing to extract it. When that happens, shift to the slide hammer puller. Then use the slide hammer puller and the original bolt that is still in the hole to remove the lower lock.
 

paul s

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Success! The puller idea worked very well, a bolt, a washer, and a socket. I knocked the lower one out with a drift and hammer. There did appear to be some corrosion where the lower one sat. Onward and upward.
 
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