I've wanted a lathe for years. I'm a member of a model engineering mailing list, I love reading about machining on the web, I have a few books on the subject, I've even thought about building my own lathe from homemade castings. The only problem is I have neither the space nor real need for a lathe. I'd use it from time to time, of course, but it the grand scheme of things it's hard to justify even a small hobby lathe. Somehow, I doubt I'm alone.
The thing is, there are times when a lathe really is the tool for the job. Especially if you're thinking about scratch building or heavy kitbashing, sooner or later you're going to want something round. What do you do? I built my own lathe! Well, sort of. See for yourself. This is based (somewhat loosely, admittedly) on the Fonly lathe (as in, "If only I had a lathe.."). Here's my version:
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You can probably figure out how it's built just from that photo, but I'll describe it a little. Bear in mind, I'm no expert, just a guy armed with a tiny bit of knowledge and a willingness to break something.
The heart of the lathe is an old drill. I bought it at a thrift store for $5, I believe. It's nothing fancy, and it sounds horrible, but it works. The two most important parts for my purposes are the trigger lock and the handle mounting holes on each side. The trigger lock is obvious - I pulled the trigger in all the way and locked it in place, since I made my own variable speed control for the lathe - more on that later. The handle mounting holes are what I used to mount the drill in the homemade wooden cradle. Most are 1/4" bolt thread, and I happened to have a couple bolts with wing nut heads in the garage. Fortunately for me, this particular drill has nice flat parallel sides, so I can really clamp those bolts down tight. The drill can still tilt up and down a little, but so far it hasn't made any difference. If I ever feel the need to make a tail stock, I'll take the time to get the drill mounted more rigidly and with the spindle perfectly level.
To control the speed, I mounted a nice inexpensive metal box on the base board, and wired a light dimmer into the power cord. This particular dimmer (maybe all of them?) has a very handy push on-off feature, and mounted as it is all I have to do is hit the knob to turn the lathe on or off.
I tried making a face plate out of plywood, but it was less than a success. Mounting is simple enough - the drill spindle has 5/16" (I think) fine bolt threads, so nuts and bolts can be purchased at any decent hardware store. So far, though, I've found that the standard chuck seems to be suitable for most of my needs, and it's a lot better than anything I can build easily.
Since most of what I'm doing is going to be either brass or styrene, and also since a lot of it will be odd shapes that are difficult to machine perfectly, and since I didn't feel like making anything fancy, I decided to forego the typical tool post. Instead, I grabbed a few scraps of plywood which put my cutting tool at about the spindle height. I simply hold the tool in my hand and shape things free-form, however looks about right.
Speaking of tools, I tried my best to make files work. I tried using the cutting surfaces, the flats, even the tangs. They work, sort of, but they do more mangling than cutting. I finally had to bite the bullet and invest in.. a screwdriver. Somehow or another, I wound up with an old flat blade screwdriver with a bent shank. Maybe I bent it trying to pry on something (probably) or maybe someone else did and I inherited it. However it came to me, it's useless as a screwdriver. I filed one face nice and flat, then the tip and both sides flat and angled away from the face, making three cutting edges at roughly 90 degrees to one another. The handle is a lot easier to hold that the tang of a file, and with this tool I can easily shave down styrene. I haven't tried it on brass yet, but I'm expecting good results when I do.
I also made myself a spindle for holding small pieces of styrene. Styrene is soft enough that the chuck jaws will simply destroy it, and the force of cutting could twist small pieces right out of the jaws. I took two telescoping pieces of copper tubing and soldered them together, with the smaller piece extending out beyond the larger by about 1/2" or so. This I drilled and tapped for a 00-90 screw, the head of which is very slightly larger than the tube. The dimensions are not critical - what matters is that I have a metal piece which I can mount in the chuck, and onto which I can slip anything with a hole of the right diameter and clamp it down with the screw. I have used this to turn steam and sand domes, and most recently this little gem:
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The picture is a little fuzzy, I know - it's an enlargement from the previous photo. That's a smokebox front for my Porter. I started by rough cutting and gluing up three layers of .040" styrene, along with a tube to make the stack long enough to clap onto my spindle. In the photo, you can see that I've turned a step on the back to fit inside the smokebox tube, and turned down the door on the front.
So, there you have it. For less than $20, plus a little time and some scraps of wood, I have a lathe suitable for 90% of my model railroad needs, and I can improve it in the future if needed.
