Last November I did something really stupid: I bought a metal lathe on eBay sight unseen. In my defense, it was ridiculously cheap because the owner knew nothing about it and needed floor space more than 2,000 lbs of cast iron. The process of bringing this home led, in a roundabout way, to the last shopski. I could probably put together a whole post on that story.
The lathe itself is a Hendey 14x6 made somewhere between 1915 and 1918. Back then, Hendeys were very nice industrial-quality lathes; this thing was built to cut threads on oddball parts as well as do most anything else you can do on a lathe. It was made to run off a line shaft. Since nobody uses those anymore, sometime in the '50s it was retrofitted with an electric motor and a transmission.
One problem it has is the pulley on the transmission output shaft is concave, so the belt wants to run off the pulley when I run the lathe clockwise. It's also too small, so the speeds I can get on the lathe are too slow. With the current 4-speed gearbox and output shaft pulley, I have speeds 71-108-142-178 RPM!
Here's a mediocre picture of the old pulley:
Here's a picture after I put the new pulley on:
Now, I probably should have made this out of hardwood, but I have never turned anything in a lathe before and I didn't really expect this to come out that well, so I made it out of some glued up 2x4 scraps I had laying around. Made a roughly 4.5" square chunk, then used my table saw to cut the corners off at 45* to reduce the amount of turning I'd have to do.
Chucked it up in the 4-jaw and got it sort of centered. At first I tried holding the chisel in my hand braced against a tool holder, but that did not work well at all, so I used a tool bit to shim it into a big tool holder.
Roughed one side in pretty well, then turned it around in the chuck to do the other side. Centered it up by spinning it at a low speed and holding a pencil braced against the carriage to mark the high spots.
Rough faced with the chisel held flat:
Then turned the chisel 90 degrees and smooth faced it. This is the second side I did...the first side did not turn out so well, so it is going on the gearbox side so you can't see it very well.
Took me two shims to hold the chisel sideways. The only thing I have to say about this approach for holding chisels in a tool holder is that it works:
Center bored with a 1" spade bit. Should give a hammer fit on the output shaft.
Since I figured pine wouldn't take kindly to me trying to broach a keyway in it, I drilled and countersunk two holes for some blunted wood screws that will sit in the keyway on the output shaft. Hopefully that'll hold it pretty well in combination with the friction fit.
Fit it onto the output shaft, then turned the motor on and sanded it in place to put a slight crown on the pulley and clean up the rough faces. Took me a few test runs, but I eventually got the belt to track right both clockwise and counterclockwise.
The new pulley gives me a 2:1 reduction, so my new speeds are 108-162-216-270 RPM. Not exactly where I want them to be, but better than before for sure. I am going to have to figure out some way to change the gearbox ratios because they are way too close right now. The bigger pulley also eliminates a weird idler pulley that a previous owner grafted on at some point.
So now you have some background for my next project. Here's a vague drawing; can you guess what it is?