Craftsman 109 broken lead screw sleeve

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ericc

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I have made a little progress on the lead screw gear problem. Earlier, I tried pulling the gear, and ended up shearing off some kind of keyed sleeve. The broken end of the sleeve was very difficult to extract. There was a spacer on it, but the spacer could not be removed, because there was no place to put a puller on it. The other end was covered with a washer, and the washer would not budge. Eventually, I decided that it was time to use some heat and force. I put the puller on the washer, and heated the sleeve with a torch, continually applying force. Finally, it broke free. It was obvious what was sticking things together. The sleeve was pinned with a hidden pin that was covered with the sleeve. With enough heat, the washer pushed the sleeve through the pin, and zamak sand poured out the end. This was not recoverable, but I did try to put the sleeve back together. It did not work.

All the trouble started because the sleeve was too tight in the bore of the gear. A sleeve that is cast that thin should not be made such a tight fit. Also, being made of zamak, it is more prone to shear. Anyway, it is time to make a replacement. One of my machinist friends suggested making one out of steel, but he said if I used this little lathe, I would have to settle for aluminum. Wy is that? Is it that steel can be silver soldered (for attaching the keys)?

As long as threading is not required, the lathe seems to work fine. I was able to turn down the shaft of a junk drill chuck so it would fit in my tool block. Now, the lathe can drill holes in the ends of rods. It was slow going with some chatter, but it cut and worked well. Got chips!
 
I can't even guess why someone, especially a machinist, would tell you you can't make that part from steel and you would have to settle for aluminum. That comment sounds more like attitude than sound advice.
 
I'm supposed to know all about AA109 lathes, and this assy. sounds weird and misguided. Should have two key slots,separate keys,maybe a spacer or small gear a 64 tooth with grooves to match
the keys,all held together with an oversize washer and short round- head screw. Picture or sketch
might help. Happy to offer further help! BLJHB.
 
Hi Spiral Chips. Yes, that is strange. He has some experience with the Craftsman 109 lathe, and says it is only good for aluminum. When I tried it on aluminum and steel, it worked just fine. Just went a little slower on the steel. He does not know how difficult it is to TIG weld a small aluminum assembly like this without leaving a sag or a crater.

Hi Liberal Arts Garage. This is exactly what I thought when I saw the odd design. It is poor machine design practice. The arrangement that you refer to is the way the 109-270 is made. I have the 109-703, which is the later, and apparently, cheaper, model. It eliminates the need to machine two key slots and a circlip groove in the end of the steel shaft, and replaces it with a zamak casting.
 
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