Craftsman (Sears) 109.20630 Metal Lathe Rescue

While at an old tractor/engine show this past Friday, there were also the usual vendors selling just about anything you could think of. My wife and I perused the $1 DVD collection a fellow had and found some videos we liked. He also had an old Craftsman lathe laying forlornly on the ground at the outskirts of his vendor kingdom. I didn't need another project so I didn't even ask a price when I went to pay for the DVDs. My wife then asked me if I'd asked about the lathe. I said no. She then persuaded me to go ask. Big mistake. The guy said he'd take twenty bucks for it. (!) That was even too cheap for me to pass up, so I came home with another project. Friday was a good day to go to the show, if for nothing else but to get the good lathe deal, as it was a pretty quiet day for visitors.

Yes, this poor 75-year-old lathe has seen better days. It was, surprisingly, fairly complete except for a tool post, motor, chuck, and a set of change gears for threading operations, however everything was rusted up solid. Fortunately the cross slide handle was the only thing actually broken.

These tiny lathes are commonly known as "109", as that's Sears' designation for Double A (or AA) Products (Ann Arbor (Michigan)).

At least there were these gears to run the lead screw.

The first order of business was to start the disassembly process. Every nook and cranny was filled with mason bee nests, so the poor lathe probably sat outside for a long time.

The "back gear" drive is a planetary setup and not the typical set of gears on the backside of the headstock. The ratio is 5:1.

I was able to get the gib out of the compound slide and got the threaded rod to move well enough to disassemble the compound. More bee crud.

I initially couldn't get the gib screws loose in the cross slide so I had to judiciously use a hammer and brass drift to slowly get the slide to move. I also had to use vice grips on the end of the threaded rod (gently... and where the handle mounts) to get it to turn. Things finally broke loose.

Everything is back together in the below photos and all the movable parts are, well, moving.

I did have a very difficult time getting the tailstock freed up. Unfortunately it had been left in an extended position during its lengthy stay in the elements. I finally got it moving though.

There is a set screw on the backside of the tailstock to keep the ram from rotating in the tailstock. A word of caution, the set screw cannot be removed with the ram still in place in the tailstock, as it is "keyed" to the ram (more on this later). I didn't know that at first and futilely tried getting it unscrewed. One major problem was that I didn't know the ram needs to be removed first, then the set screw will come out. However, once I initially got the ram free, it cranked out about an inch, then abruptly stopped, making me think that was normal and that the set screw needed to be removed in order to get the ram completely removed.

Fortunately my efforts to free things up were somewhat tempered and I didn't damage anything. Not until I watched a YouTube video from Hand Tool Rescue did I see that the ram was designed to come all the way out with the set screw remaining in place, and that the set screw was "keyed" or slotted to the ram (see 16:14 of this video 1940s Metal Lathe and below for a better look at the set screw). I had erroneously guessed the set screw would be "normal" and have a rounded (full dog point) end to fit into the slot.

It's kind of difficult to see, but there is a rectangular protrusion on the end of the set screw. The thin flat washer is something I made to take the slack out of the ram/handle. It is about .030" thick and before I installed it, the handle would turn more than one revolution before the ram started to move.

The next order of business was to make a makeshift handle for the cross slide. Stay tuned.