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9A Worm Gear Collar

NCarolinasailor

Plastic
Joined
Oct 28, 2019
I don't know if I have just lucked into the most stuck lathe ever but I got the retaining pin out but the collar is seized up tight (I saw in that video from Mr. Pete his looked to only be a bit more than finger tight. The trouble is finding some way to put force on it that holds the worm gear from moving, and doesn't damage any gear teeth. Has anyone dealt with a stubborn collar?

Thanks for all your help!
 
Curious, what part of NC are you in? Could probably give you a hand if you’re not too far from 28571.
 
Depending on how torn apart your whole machine is you have options. I've inserted the leadscrew and worm key back into the worm gear and then used rubber jaws in my vise on an unimportant part of the leadscrew to hold it in place while I use a sturdy pin punch inserted ONLY into the collar as a lever to break it loose. Kroil can help.
 
I just watched the video I took in July 2016 when I disassembled my 1948 9A. I had forgotten the DIFFICULTY of removing the pin from that collar (it eventually yielded to drilling), and the EXTREME DIFFICULTY of unthreading the collar. I was finally successful by using channel lock pliers -- very well cushioned -- to hold the worm while using a punch as a lever -- through the collar only -- to rotate it. It was very tight. Once it broke loose, after a bit of back-and-forth turning, it soon could be easily unthreaded using just my fingers.

I then chased the threads on the worm and dressed the pin hole.

I think the next person who disassembles this part will appreciate that I replaced the pin with a set screw.
 
Got it done and here's how. Inserted leadscrew and key back into worm gear then used a wrench at the smooth part with keyway and used an allen wrench laying in leadscrew keyway with a wrench to hold the whole thing in place then used pin punch to turn the collar. It was tight enough to bend the punch but got it moving and after that it came loose quickly. I think it is the combination of a slight bit of rust on the threads at the end and a burr created by the pin. Thanks for the suggestions everyone!
 








 
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