10L QC Gearbox Bushing Question (Single Tumbler)

[opsoff1]

I have a 1945 era 10L Toolroom lathe. Model CL 8187ZN that needs some serious freshening up. As I start to tear this machine down (first time - gulp) I am finding other issues - one of which is really eating at me - the bearings on the left side of the QCG (single tumbler type) appear to be seriously worn.
The shafts actually wobble with finger pressure and one of them has no felt in it at all.

Is there any source these two bronze bearings? I have been scouring the internet for everything SB - with no luck.

I am trying to ID the part number - through an old parts book - are they #429 & #601??

Any help would be HUGELY appreciated.

Scott

 

[SLK001]

If all the wear is confined to the inside of the bushing, it should be no problem to make them yourself. Making them yourself will probably be faster than trying to source them for a part that was discontinued in 1947 time frame. Just get yourself some bearing bronze and get with it. If the left side bushings are worn, chances are the right side bushings are too.

 

[opsoff1]

If all the wear is confined to the inside of the bushing, it should be no problem to make them yourself. Making them yourself will probably be faster than trying to source them for a part that was discontinued in 1947 time frame. Just get yourself some bearing bronze and get with it. If the left side bushings are worn, chances are the right side bushings are too.

Thank you. The wera appears to be confined to the ID only. I am starting to wrap my head around making them - I have not taken the gearbox apart yet, so I really don't have a good understanding of what they look like. Are they flanged on the inside? I see the key way cut for the felt. Is there a hole in the side to feed oil to the felt?
The right side looks like the shafts are running on the casting - I can't see any bearing on the right - are they insert from the inside??
Any Chance someone has a picture or even better a drawing of these bearings?

 

[johnoder]

17-C says 601 and 601-A for gear box bushings. They appear as being similar - no flanges.
A good thing to have is the Boston Gear catalog - let's one see what is available

 

[SLK001]

Thank you. The wera appears to be confined to the ID only. I am starting to wrap my head around making them - I have not taken the gearbox apart yet, so I really don't have a good understanding of what they look like. Are they flanged on the inside? I see the key way cut for the felt. Is there a hole in the side to feed oil to the felt?
The right side looks like the shafts are running on the casting - I can't see any bearing on the right - are they insert from the inside??
Any Chance someone has a picture or even better a drawing of these bearings?

I don't have access to a single tumbler gear box, so it looks like you may have to disassemble it partly just to get the info you need on the bushings. It also looks like only one shaft has a bushing on the right side. I have heard of others boring out the shaft holes to make room for a bushing (after massive wear on the cast iron body). Wait a couple of days for someone who may have rebushed the shafts to see if they chime in with dimensions, etc.

Meanwhile, here is the parts drawing for the single tumbler of the H10 variety.

 

[opsoff1]

Crazy helpful! The shafts on the right side ride in the cast housing and ironically - appear to have waaaaay less wear / clearance than the bushing have on the left side.
Guessing the bronze bushing didn't get oil during some stretch of use. Hopefully someone will have rough dimensions so I can order a bushing that is close and I can hone to fit.
Thank you again.

Dimensions anyone??

Scott

 

[kitno455]

If the bushing ID is worn, the shaft OD is also worn. You may need to make a cleanup pass on the shaft. Hence, no one can give you dimensions that will be accurate to your situation. Take it apart, and start measuring.

 

[Gard]

American Sleeve Bearing (https://asbbearings.com) is a company I have used several times, sometimes they have a direct fit but other times I end up getting something oversized and machining it down to size. As others have said take it apart and see what you need. I will be doing the same to my 10L shortly.

 

[opsoff1]

Gaard
Thank you - I was able to find a +OD and -ID cast bronze sleeve from ASB. I should be able to machine it to fit.
The big issue I have is trying to figure out how to machine the - maybe 1/3 radius for the retaining screw that is machined into the OD of the bearing.
Some how - someway the threads must align with the treads in the gear box casting.
Thoughts?

 

[opsoff1]

I don't have access to a single tumbler gear box, so it looks like you may have to disassemble it partly just to get the info you need on the bushings. It also looks like only one shaft has a bushing on the right side. I have heard of others boring out the shaft holes to make room for a bushing (after massive wear on the cast iron body). Wait a couple of days for someone who may have rebushed the shafts to see if they chime in with dimensions, etc.

Meanwhile, here is the parts drawing for the single tumbler of the H10 variety.

View attachment 390464


View attachment 390465

SLK001
Where can I find the publication that has this (and other) exploded diagrams w/ part numbers?

Thanks

Scott

 

[texasgeartrain]

Another tactic that may work for you. Bore and bush the existing bearings. This would allow you to keep existing features for keys, screw slots, etc.

A different machine, but similar issues. I had wore out bushings:


The shaft in this case, was both ends of a worm gear:


I first cleaned up worm gear to know what my new bushing ID would need to be:


I then bored out the old bushings larger, to press a new insert bushing into them. With new bushing inserts pressed in. I bored each ID to .001" to .0015" larger than each mating shaft to allow for oil clearance, which is kinda standard for spinny things. I cut extra oil slots and such, but you don't need to get too fancy:


You could do the same. If your lathe has power to it, you could even manage it without qcgb, so long as spindle spins, and you can run carriage and cross slide by hand.

For raw material, love c932 bearing bronze. Figure out your dimensions, and get a piece of 'cored' or 'hollow round'. And a good source for it here:

C93200 SAE 660 Bearing Bronze Alloys | Bravo Bronze

View C93200 SAE 660 Bearing Bronze alloy bar stocks in solid round, flat or cored shapes, various sizes and thickness. Request a quote!

www.bravobronze.com

 

[SLK001]

SLK001
Where can I find the publication that has this (and other) exploded diagrams w/ part numbers?

It's South Bend's CE3458 PARTS MANUAL for 10", 13", 14-1/2", 16" and 16/24 LATHES. I got it with my lathe and I scanned it into .pdf form. I believe that there are copies floating out in the ether somewhere.

 

[kitno455]

Gaard
Thank you - I was able to find a +OD and -ID cast bronze sleeve from ASB. I should be able to machine it to fit.
The big issue I have is trying to figure out how to machine the - maybe 1/3 radius for the retaining screw that is machined into the OD of the bearing.
Some how - someway the threads must align with the treads in the gear box casting.
Thoughts?

Just file or mill a round-bottomed slot in the bearing, clamp it in place, and run a tap through the existing hole. It will follow the old threads, and cut new ones in the bearing. It is a low-precision part here.

 

[opsoff1]

SLK - huge help - thanks a ton.
Texas - I was able to source an +OD/-ID bronze bushing stock from ASB Bearings.
Kitno - I figured I'd hit the bearing with a ball end mill that is close enough for the tap to follow.

The glitch in this - it is really more of a PITA, in that I will need to remove the headstock to get to the 3rd screw that holds the gearbox on - then reinstall the headstock and machine the bearings to size / remove the headstock again - reinstall the gearbox and reinstall the headstock for hopefully a final time.
This all assuming the gearbox internals come apart without any stubbornness. It is very well lubed and I have been able to look up inside with a small fiberoptic camera - I can't see any issues..

SO!

Question of the Day...
If I drilled / tapped two or even 3 holes in the exterior face of the bearing and used the screws with a small plate w/ a center hole tapped for a larger bolt against the shaft(s) - what's the chance of being able to pull the bearings out of the gearbox this way?? If it worked - I'd be able to turn the new bearings with out R&R the headstock 2 or 3 times.

 

[texasgeartrain]

Question of the Day...
If I drilled / tapped two or even 3 holes in the exterior face of the bearing and used the screws with a small plate w/ a center hole tapped for a larger bolt against the shaft(s) - what's the chance of being able to pull the bearings out of the gearbox this way?? If it worked - I'd be able to turn the new bearings with out R&R the headstock 2 or 3 times.

It is possible, some might come out with some nudging from a pry bar or screw driver from the interior as well. Though I'd remove and re-install one bearing at a time if this way.

One downside, you won't be cleaning up, or truing the mating shaft journals, if this way. . . Though no doubt you'll have tighter clearance than what is currently present.

You also mentioned single tumbler. . . I've found this vintage lathe with single tumbler, one side of gear in tumbler arm is not supported. This can wear and cause great slop in the shaft and tumbler arm. If you have similar you might consider a repair. I bored and bushed tumbler arm much how I described above. A little detail in post #3 here:

Getting Another South Bend 16x6 Operational

South Bend Lathe 16x6 Catalog No. 8117C Serial: 134696 Ship Date: 2/11/1943 I didn't plan on doing a thread for this lathe, as I've already done similar, but I hadn't started a thread in a while and I actually accumulated a bunch of pics, so for your viewing pleasure. . . I purchased this...

www.practicalmachinist.com

 

[SLK001]

Removing the headstock isn't all that difficult. Remove two nuts on two bolts accessible from underneath, remove the belt, then lift the HS off. You'll spend more time looking for the correct wrench to remove the two nuts (7/8", IIRC).

 

[opsoff1]

I have yet to find a single thread / UT video of anyone who has had an easy time of disassembling/reassembling these single tumbler gearboxes.
Waiting for my bushings to arrive...and then its off to the races. <gulp>

Another question - there is a hole on the front of the gearbox - upper left that has an oil tube attached - simple enough. Was there a Gits cap originally in this hole or a plug or ????

 

[texasgeartrain]

Another question - there is a hole on the front of the gearbox - upper left that has an oil tube attached - simple enough. Was there a Gits cap originally in this hole or a plug or ????

No gits, just an open hole. Stick the tip of oil squirt can in and shoot in. Position tumbler under the tube, and let oil drip onto tumbler gear.

 

[opsoff1]

No gits, just an open hole. Stick the tip of oil squirt can in and shoot in. Position tumbler under the tube, and let oil drip onto tumbler gear.

High tech!! LOL I wonder why no Gits?

 

[opsoff1]

Short update...
I did the whole remove / replace drill with the headstock & gearbox - gearbox is off the machine and the headstock reinstalled so I can use it to make the new bushings.
Got in the bronze cored stock and started out to disassemble the gearbox. Happy to report that it came apart very easy. Pins popped out, thin 1" wrench got the nut off the shaft fairly easy. No heatin' n beatin' required for any of it. The old bronze bushings came out very easily too.
The OD is interesting - .968 (31/32). The ID...??? way to worn. The end of the shafts are worn too. They came in at .531" & .538". My plan is to turn to .499 and mate them up with the cored (@ .500") bronze bushings - I may need to kiss them with a reamer to ensure uniform ID but they measure out pretty good. I can turn the OD to match easily enough and I have a broach/insert to cut the felt keyway. I'll mill a small relief with a ball end mill for the lock screws on the OD and drill the oil passage hole when they are in the housing. Once past this, its a deep clean, paint, lube & reassemble.
I appreciate the advice and encouragement - all of this has been an eye opening experience and really satisfying to learn about the internal guts of these machines.
More to follow..

Thx to all.