South Bend 9A Back gear

MBY9A

MBY9A

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Looking for just the 2 gears. Don't need the whole assembly. Guy I bought it from said there were no broken teeth. 2 teeth broken off on smaller gear. There just about opposite each other. Not sure if thats a big deal or not.

Thanks, Mike
 
Missing teeth are never a good thing, whether in our mouth or part of a machine, with a machine, it tends to put a higher load on adjacent teeth, possibly causing loss of more teeth, effectively causing loss of function.
 
there's a guy (tommo1010?) in the South Bend section of PM that's selling 9A back gears for $150 each. One of them has already been claimed. For that money I'd try the set screw and JB Weld fix, but your aims (or wallet!) may be different.
 
My SB9 has had 2 teeth replaced on the small back gear.
I’ve had the lathe 35 yrs, have cut threads many, many times, works great.
Didn’t even know it had been repaired for years.
Looks like drilled & tapped for 6-32 screws, then filed to fit. Probably by the shop teacher after a student engaged the back gears & hammered on the chuck to remove it.
The lathe was abused for many years by students, & lived to tell the tale.
And still makes accurate parts.
 

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I didn't realize I should of inquired about dental insurance when I bought it, live and learn!!
 
mattthemuppet2 said:
there's a guy (tommo1010?) in the South Bend section of PM that's selling 9A back gears for $150 each. One of them has already been claimed. For that money I'd try the set screw and JB Weld fix, but your aims (or wallet!) may be different.
Click to expand...
That is a little pricey so maybe I'll look into getting implants. I saw a couple on ebay and they were upwards of $200, wow! I'll have to see if I can find some videos on that fix.

Thanks, Mike
 
Manual Mac said:
My SB9 has had 2 teeth replaced on the small back gear.
I’ve had the lathe 35 yrs, have cut threads many, many times, works great.
Didn’t even know it had been repaired for years.
Looks like drilled & tapped for 6-32 screws, then filed to fit. Probably by the shop teacher after a student engaged the back gears & hammered on the chuck to remove it.
The lathe was abused for many years by students, & lived to tell the tale.
And still makes accurate parts.
Click to expand...
That's good to know. I saw one video on youtube where the gap was filled in by brazing and then filed to fit.
It just makes me mad that I checked every gear on this lathe before I bought it and wouldn't you know that one I didn't check. If I knew more about people using it to release a stuck chuck I would have checked it. Maybe the PO didn't use the back gear and wasn't aware of it. I probably won't be using the back gear anytime soon for anything but I'll keep searching and researching on fixing it.
I like how your's was fixed, that's pretty clever.

Thanks, Mike
 
Last edited:
martik777 said:
I had 7 missing teeth on my bull gear, repaired them all with custom made screws in a couple hours. The smaller backgear was completely stripped, so I made a new one out of AL and pressed it on with a keyway. You will have to click on the 6th image of the custom screw: (for some reason the limit is 5)
https://imgur.com/prnt9K6
https://imgur.com/iYT1f2e
https://imgur.com/zRqlVIp
https://imgur.com/uwD1py2
https://imgur.com/d8KSS7n
https://imgur.com/u2ew3Uz
Click to expand...
That's impressive! You did a great job on that repair. Working on a wood lathe for over 50 yrs is nothing like the problems that you have with a metal lathe. The only thing on a wood lathe is replacing bearings that may go bad or a belt/ motor. If I can't come across a used one for a reasonable price which I probably won't , I'll give it a go with the screw method like you guys have did. Thanks for sharing your pic's on that repair !

Mike
 
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