Monthly Archives: March 2018

One thing I've been doing a lot of lately on the lathe is cutting threads. One trouble with cutting threads with a handheld die holder is keeping the die precisely perpendicular to the work - even something that looks perfect to the eyeball might be a degree or two off, which can be pretty noticeable when the surfaces don't make perfect contact when you screw them together. And it isn't like with wood, where you can force the joint a bit and crush everything together slightly to hide a slightly-off joint. So one solution to this problem is make a die holder that rides on the tailstock, to keep it both perfectly aligned with the axis of the lathe and perpendicular to the shaft being threaded. Over the past couple of weekends I've been making my old tailstock die holder, as you can see below. The tapered shaft on the left mounts in the tailstock, and the die holder (on the right) rides on the narrower half of the shaft (which isn't tapered). The narrow bar in the middle can be screwed into the body of the die holder if a little more torque is required. The recess at the end of the die holder is where the round dies are mounted when in use. The die holder was made from aluminum (to keep it light), and the rest of the parts are made of steel. This was my first experience turning steel. It went better than I expected, but I've got some reading to do to learn what cutting tool edge geometry works best for steel.

In the back of my head I had been planning to buy a mill sometime next year to grow my burgeoning new hobby - that was the soonest I thought I could justify the expense to myself, and I wanted to give myself time to make sure I would enjoy this work before I spent the money to tool-up the metal shop. But recently, while chatting with a friend in the office about the fact that I am getting interested in metalwork, another coworker mentioned that his mother was trying to figure out what to do with her husband's old milling machine. Apparently he used to restore old outboard boat motors, and had a lightly-used milling machine. I bought it from her for far less that a brand-new (and less capable) mill would have cost me. I got a great machine, and she got a good chunk of her garage back - win-win! It's a Burke #4 horizontal mill, and is quite a beast. It was built in 1942 and is about 600 pounds of American-made cast iron. To get it home, we had to take it apart - but even then, those parts were probably at least a couple of hundred pounds apiece! The van was definitely riding low on the trip back.

Once I got it home, I took it apart further into assemblies I could work with. Then I scraped and sanded out the rust on any of the metal-to-metal sliding surfaces. As you can see in the photo below, there was a good amount of surface rust that needed to be removed - but there was no deeper pitting - which was great news. Once I got everything apart, cleaned up, and oiled I put it all back together in the room I actually wanted it to end up in - which you can see in the top photo. I got it all wired back up and powered it up to make sure it still worked, and it started right up. I've tested all of the axes, and everything is moving smoothly with minimal backlash. I have yet to try and make any chips with it, but now that I've handled every part of the machine I feel like I've got a very good understanding of how it works and what I can do with it.

Originally I was keeping all of my cutters in a drawer in the toolbox below the bench. But that became kind of a pain, because I needed to root around in that drawer every time I wanted to try a new cutter. I needed to get them up at eye level, so I could more easily see what I have - especially while I'm a newbie and have no idea which cutter I should be using for any particular operation. :)

A couple of weeks ago I made a fire piston on the lathe, but forgot to post about it. For those who haven't heard of a fire piston, they are a way to start a fire without matches using adiabatic compression. When you compress the piston quickly, the air inside heats up enough to ignite a piece of tinder held is a slight recess at the end of the piston. This one was tough because the tolerances had to be just right to prevent air from escaping when the piston was compressed - I actually ended up having to make the piston twice - on the first one, the o-ring didn't quite seal the chamber. For materials, the main part of the handle is aluminum, the handle end cap is brass, and the piston is brass. It can't be seen from the pictures, but the top cap of the piston can be unscrewed to reveal a small storage compartment in the piston - this can be used to store extra tinder (char cloth, specifically).