A couple days ago, my new mini lathe arrived on the front step. Luckily, I have earned enough brownie points with my wife that she helped me heave the heavy bugger into the basement where my "shop" resides. That first evening, I unpacked the lathe and began cleaning the Cosmoline from it. I noticed a few problems with the machine, so I am in the process of getting the machine dialed in. Here is what I did last night: (reposted from my Introductions thread)
I tore down the entire machine last night. Nothing went untouched. Every single moving part of the lathe got a thorough scrubbing with mineral spirits and a good wipe with clean rags. As I began to put things back together, I lubricated what needed it with a good 10W30 and checked operations. Here's some of the more interesting finds:
Virtually no fastener on the machine was tight. As I disassembled the compound, cross slide and carriage, I noticed that all the fasteners were sloppy loose. The plates on the underside of the carriage that hold it against the bedways were completely loose. It took me about 45 minutes to adjust them just right, then shim the difference, then readjust. Once done, I had to work the carriage onto the bedways, but it moves very smoothly and there is NO play. It might be a bit tight, but new equipment always is until it gets some use. Also adjusted the half-nuts so they engage/disengage the leadscrew properly. For some reason, I didn't get a handle for the selector knob, so I'll have to make one...on my lathe...LOL. I hate that I had to stack a bunch of small shims, so I'll keep eyes out for some thicker stock and redo the shimming of the carriage.
The cross slide was disassembled and cleaned. Lots of grit and grime to get rid of. Lapped the gib strip and the dovetails. Reassembled and adjusted the gib screws just right. No play in the cross slide. Much less backlash. Success.
The compound was a mess. Disassemble and clean. Again...lots of girt and grime. Lapped the gib strip and dovetails. Reassembled and adjusted the gib screws. No play. Much less backlash.
The chuck was taken off and disassembled. I wanted to change the jaws anyhow, so I figured I might as well take it all apart while I could. Gross. Loaded with gunk and grime. None of the fasteners on the cover plate were tight, nor were the bolts retaining the small gears. I cleaned it all up and lubricated it. Took my time reassembling, making sure of what jaw went where AND MARKING THE CHUCK. I used a automatic hole punch to make a single indent for #1 jaw, 2 indents for #2 jaw, and 3 indents for #3 jaw. Much better. Still couldn't find an indexing mark on the faceplate to mount the chuck, so I'll have to test when my measuring equipment gets here.
I also ditched the splash pan. It wobbled. I can live with getting the surface of the workbench oily. It'll give it character, right?
Long evening, but I have increased the fit and finish of the machine by orders of magnitude. It is now much closer to being ready to be put to work.
As an aside, I wanted to throw this out here and see what some of our machinists thought of the idea. The guy who looked over my shoulder as I was machining the apparatus for my master's research project had a neat tool he used to indicate parts in a 3-jaw chuck. It was a steel bar milled to size to fit a standard tool holder, and had a roller bearing on the end of it. He'd lightly chuck his workpiece and move this tool up to the work and you could see the piece come into alignment. When it was running true, he'd tighten the chuck. He could always get within about 0.001" of true with this little tool. I'm thinking about making one or having one made. Thoughts?
