[How do I?] Take this part of the quick change box apart?

Jmanb13

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In my quest to take apart every major component of my lathe and clean it, I am now down to one of the final parts, the quick change gear box.

BTW if you think I'm crazy for taking all this stuff apart, lets just say nothing on this lathe could be operated effectively (aka sh*t was stuck in place). You can see how gross it is in the picture below, and that is after I already cleaned it as effectively as I could before I started taking it apart. Most of this machine required me to use a screw driver to carefully scrape away hard grime before I could even tell the difference between the castings and a bolt, nut, or screw.

Back on topic.

I got all the gears removed but I cannot for the life of me figure out how to get the tumbler gear (21) out so that I can remove the yoke (24). The yoke sits on cylinder (30) but the tumbler gear prevents it from sliding off either end without being removed.

I know I have to remove the shaft (23) but seeing as it is inside of a very tight space inside of the gear box, its not like I can get a hammer or punch to either side of it and actually be able to tap it.

Anyone have any ideas on how I would remove the tumbler gear shaft (23)?

Also fun note, pin (22) was absent. The hole is there, but the pin was either misplaced/fell out/never installed


quickchange2.JPG
quickchange.jpg
 
Are you sure there isnt a piece of pin 22 still holding it together? Or perhaps someone put another pin through in a different position? It certainly looks like thats the key piece that holds it together.
Does your shaft 23 rotate in the yoke, or does gear 21 spin on the shaft? If the shaft doesnt rotate perhaps someone has pinned it into the yoke.
Could you get a small g clamp in there? Cut a piece of tube to provide clearance at one end for shaft 23 to slip in to and a small piece of solid at the other end to press on the shaft

Cheers Phil
 
Kieth Ructer out at Vintage Machinery is bringing a LaBlond back to life.
LeBlond Lathe Restoration - Part 5: Quick Change Gear Box Cleaning and Disassembly
There are several videos of removal, disassembly and reassembly of the quick change gear box.

 
Are you sure there isnt a piece of pin 22 still holding it together? Or perhaps someone put another pin through in a different position? It certainly looks like thats the key piece that holds it together.
Does your shaft 23 rotate in the yoke, or does gear 21 spin on the shaft? If the shaft doesnt rotate perhaps someone has pinned it into the yoke.
Could you get a small g clamp in there? Cut a piece of tube to provide clearance at one end for shaft 23 to slip in to and a small piece of solid at the other end to press on the shaft

Cheers Phil

23 rotates in the yoke along with the gear (21). In my inspection it doesn't look like the gear has any pins holding it in place. I can see that the taper pin hole is not in perfect alignment between the gear and the shaft, it has slipped slightly, so I do not think there is anything holding it from rotating or sliding except for friction and grime. I don't have a clamp that small, but i'll pick one up and try the tubing method. its a really tight fit, so I'm not sure if even a small clamp would be able to clear the yoke but still have clearance for the clamp screw.



Kieth Ructer out at Vintage Machinery is bringing a LaBlond back to life.
LeBlond Lathe Restoration - Part 5: Quick Change Gear Box Cleaning and Disassembly
There are several videos of removal, disassembly and reassembly of the quick change gear box.


Thanks Reeltor! I have actually watched several of those videos, they have been very informative and helpful on several parts of the lathe. Unfortunately those videos are for a larger version of the leblond and the quick change gear box on the 15" is different. That one in the video is easier to take apart :)
 
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I don't have a clamp that small, but i'll pick one up and try the tubing method. its a really tight fit, so I'm not sure if even a small clamp would be able to clear the yoke but still have clearance for the clamp screw.
Hmmm ... instead of a traditional C clamp, you might be able to get a Kant Twist to work. Unlike a C clamp, the clamp screw is perpendicular to the working axis. The only downside/caution I can think of is that the Kant Twist has swiveling contact blocks, so holding everything in alignment might be a bit tricky.
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Not sure if I should start another thread, but I do have one more question.

How the heck do you remove a pin that isn't fully through?

Pin 38 is labeled a straight pin, thus I assume it is not tapered. The hole it is in does not go all the way through so I cannot punch it out from the backside.

2017-01-12 20.44.06.jpg 2017-01-12 20.44.24.jpg
 
Kudos for your success outside the box!

As for your next question, it's kind an interesting problem. Might you able to disassemble the rest of the plunger, leaving the pin and the small shaft (37) permanently in place? If so, you could simply treat parts 24, 37 and 38 as a single unit. What I can see of the parts diagram doesn't seem to show any features on 37 that would permanently hold on to the other parts (31 thru 36).

If you absolutely have to remove 38, you might be able to do so by drilling a smaller diameter hole from the opposite side and using some kind of drift to knock it out. By making a smaller hole, whatever feature keeps the pin from going in too deeply would still be largely there.
 
You could drill pin #38 and maybe use an ezy-out.
Or drill through the full length of the pin but not the hole it is in, (might be hard to gauge). Then use grease and a neat fitting punch to hydraulic it out.
Or drill it as close as you can to the diameter and just collapse the wall.
Or drill it oversize and replace with a larger pin.

Cheers Phil
 
pin 22 looks a similar length in the drawing.
work out how you think pin 38 is likely to be holding what ever it is holding
you should be able to make a good estimate of the pin length and drill the pin out.

pete
 
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