A friend in my tractor club has a 100-year-old Dain hay press that makes bales of straw or hay. It's got a John Deere Model E 3hp hit-and-miss engine to run the press. A four-inch-wide flat belt drives the press. One minor problem is, the 5-inch-diameter belt pulley on the engine is too small, so the press runs very slowly.
The hay press owner got a guy to fabricate an eight-inch-diameter pulley to replace the small pulley but it wasn't really usable, so the owner scrounged up a piece of eight-inch-diameter well casing pipe and I volunteered to try and cobble something up. Let me tell you, this is the most difficult job I've ever attempted on a lathe.
My Smithy 1340 lathe is a little too small for this job but I figured I had to at least give it a try. I chucked the piece of pipe on the outside of the three jaws of the chuck, which isn't the way to do this as it is difficult to get the pipe's centerline parallel with the lathe ways. I got it close though, and that's good enough. After truing up one end, I flipped the pipe end for end and trued up the other end. I then trued up the inside of the pipe to accept a piece of 3/16" plate to act as the pulley's mounting plate or flange.
Somewhere in this machining job I was tightening the Aloris-type tool post top nut and it broke. The nut is a poor design, as it's a very thin-walled tube that is threaded on the inside. See that line in the middle of the tube (below)? That's a split. At this point I thought the job would have to be shelved until I could either buy or make a replacement nut.
This next photo below shows the mounting plate after being welded into the end of the pipe. That was a bit of an ordeal to get the plate exactly perpendicular to the centerline of the pipe during the welding process. If it was off the smallest amount, the pipe would wobble. The center hole was then bored out to the proper size to fit the engine's flywheel, and then I started to work on truing up the OD of the pulley. It took me more than two hours just to turn down the outside of the pulley, as the steel was extremely hard and the cutting tool would often just slide along the surface of the steel. When it did cut into the steel, red-hot ribbons of steel would come peeling off (I've never had that happen before). I was surprised the carbide cutting inserts held up as well as they did. I think I went through four or five insert faces. Each insert has three separate cutting faces so it wasn't as bad as it sounds.
Also shown is the cutter holder that I had to cobble together so I could turn down the outside of the pipe. Excuse me, clearly it's a belt pulley now, not a pipe. The cutter holder was a real kluge but was the only way I could think to do it. The problem was that the lathe carriage didn't fit under the pipe, so I had to extend the cutter eight inches out to the left from the carriage. I used some 1-2-3 blocks under some 3/4" hex and square bar stock. There are two C-clamps holding the cutter to the bar stock, and two T-slot clamps holding the mess to the carriage. Yes, there was chatter and excessive noise in abundance. I had to wear ear protection. And notice the pile of pretty blue shavings that came off the pipe. There's another pile as big on the floor, and another pile back behind the lathe. After the cutting was done, I tried using a file to smooth out the chatter marks. Problem was, the pipe was too hard and just ruined the file.
I got this project completed just a few days before the local county fair. We shall see if it holds up to five days of use. Below is a photo of the hay press all ready to go at the fair.
Postscript, yes the pulley held up great during the fair and the press will be heading to the Kittitas Valley Threshing Bee in September. I'll be along for the ride to help start the engine, feed the press with straw, and tie the bales.
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