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Messed Up My SB Lathe

C

Chris Campbell

Plastic
Joined
Mar 8, 2020
Hey All,


New to your forum. I needs some help and advice. This morning I made the fatal error of moving gears while my lathe was still just moving... BANG! a few choice words after that, I knew I screwed up.
Pulled the cover off the left side and found I had sheared a few teeth off a gear. Not sure what this gear is called so I posted a couple of pictures.
Is it possible to find this piece? It's Sunday so I will call SB tomorrow, I think it's a Government unit, S/N 105631. No letters, they will most likely tell me nothing.

Dimension are; Center hole 1.1225". Outside Dia. 4.190. & .5" thick. The smaller gear was pressed in and not damaged.

I sure would appreciate any help at all, I really enjoy this lathe. Owning it for well over 20 years I just can't believe I did what I did.

Thanks guys,

Chris Campbell
 

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My best guess would be this gear on Amazon.

You'll have to bore it to size and press the small gear in. They both should be pinned together and not rely on the press to hold them together.
 
I wish I knew the model, It has a 13" swing that is what makes me think it's government, that and the green color.

Thanks so much for your help.
 
You need to know the Diametral Pitch (DP) of your gear. DP is number of teeth + 2 divided by the outside diameter (OD).

DP= (N+2)/OD

If you recheck the OD of the gear and find it closer to 4.125", then your DP is 16, like that in the link.
 
SLK001 said:
You need to know the Diametral Pitch (DP) of your gear. DP is number of teeth + 2 divided by the outside diameter (OD).

DP= (N+2)/OD

If you recheck the OD of the gear and find it closer to 4.125", then your DP is 16, like that in the link.
Click to expand...

Just ran over to the shop it's a 4.25" outside diameter.
 
It's old, not sure how old but it works great. literally built all my suspension bushings for a formula ford now building parts for a land speed roadster. Really makes you feel good to build stuff on an old loose machine.
Gear should be here tomorrow, I have a friend with a 10" SB. He has a large chuck that we can bore the center out.


Chris
 
Bore it to a light press fit. Too much pressure will crack a cast iron gear. Then, drill a hole the size of your pin right on the line where the two gears meet and pin the two together.
 
SLK001 said:
Bore it to a light press fit. Too much pressure will crack a cast iron gear. Then, drill a hole the size of your pin right on the line where the two gears meet and pin the two together.
Click to expand...

IMG_3424.jpg

Works perfect. I hung the old busted gear right above the lathe... Just a reminder :-)

Thank you so much for all your advice and help,
Chris
 
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