# Single Tumbler Gearbox - Bushing worn out



## kf4zht (Apr 27, 2017)

I am most of the way through rebuilding my 10L, down to the gearbox and getting the spindle shimmed correctly. 

Gearbox is in pretty good shape other than the tumbler gear. It is the older bushing style and it appears the oil passages got clogged. The gear bushing is worn to a taper - .682 on one end and .668 on the other, plus heavily grooved. The tumbler arm is egged slightly. 

Can I fix this by boring out the arm slightly, turning the pin down and making a bronze bushing? I don't have a spare lathe, but I do have a mill. I can put my lathe back together except this arm as long as I don't need to cut threads. 

Or is there a way to convert this to the bearing style?


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## just old al (Apr 27, 2017)

I would do as you suggest. As long as you can maintain the parallelism and basically keep everything square it should work nicely.


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## kf4zht (Jun 3, 2017)

Finished this up the other day. Got the bushings for around $1.50 off McMaster, got 2 in case I screwed one up. It was easy enough to turn down the spindle, hardest part was getting it centered with such little grip area. Kept it to an interference fit, tossed the spindle in the freezer for a while and pressed it on. 

Getting the tumbler arm setup was harder, mostly due to my inability to come up with intelligent milling fixtures. I decided that the 2 holes should be parallel, so I used a brass bar, held vertical as my alignment pin. The rest of the clamps were just to keep it from moving. The cast cut pretty easily even with Chinese carbide. 

Slapped it back on the lathe and I have power feed again. Very excited. Only thing left to do is the belt replacement. The current one works but is starting to come apart at the lacing
	

	
	
		
		

		
			








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## silverhawk (Jun 3, 2017)

kf4zht said:


> Finished this up the other day. Got the bushings for around $1.50 off McMaster, got 2 in case I screwed one up. It was easy enough to turn down the spindle, hardest part was getting it centered with such little grip area. Kept it to an interference fit, tossed the spindle in the freezer for a while and pressed it on.
> 
> Getting the tumbler arm setup was harder, mostly due to my inability to come up with intelligent milling fixtures. I decided that the 2 holes should be parallel, so I used a brass bar, held vertical as my alignment pin. The rest of the clamps were just to keep it from moving. The cast cut pretty easily even with Chinese carbide.
> 
> ...



That is a beautiful setup!


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