Turning on a metal lathe

So I bought a bunch of brass and aluminum to go along with my metal working lathe, and today I tried to turn a plumb bob.

And here’s what I learned.


(1) Make sure you have all the parts in the box. I took delivery of a 4 jawed chuck, only to find the screws were missing. (I went ahead and simply ordered the replacement screws; the theory being that at some point I’ll lose the existing screws anyway.)

(2) You can achieve some amazing precision on these lathes. Even a cheap lathe can cut objects to a tolerance of perhaps 0.001 inches. However, you get these precisions only with a lot of effort and thinking about how you are going to cut the part. For example, it doesn’t matter if you have tools that are accurate to 0.0001 inches, if the metal you’re cutting deflects 0.1 inches in the middle.

(3) It is impossible with three jawed chuck (or even a four jawed chuck) to flip the part and turn the length and have it all work out. (See the line in the middle of my picture above? That’s where I tried to flip the part.) Instead, you should minimize the number of times you remove the part from the chuck–and if that means turning the part down the entire length and then cutting the piece as a last step, there you go.

(4) You can, however, face the part after you cut it.

(5) I also learned I suck at cutting the part off. But I bought one of these metal cutting band saws, so it’s moot anyway.

(6) The amount of effort to cut a thread is just absurd. I think I want to put together a tool which can be used to mount the threading tools and turn them using the threading feature of the lathe. The other option is to develop more upper body strength.

(7) Brass is damned pretty.

(8) Also, the auto-feed lever is damned cool. When you think the cut is smooth, reset the cutting tool to the same depth and take another pass–and you find more material gets cut off. Wash, rinse and repeat 3 times and you get a nice finish.

I made a whole bunch of mistakes this morning, but I’m starting to appreciate both the capabilities and limitations of the lathe. I have a bunch of aluminimum stock on order from these guys so I can practice some more, and I also have a milling machine on order which I intend to practice with as well.

Ultimately my goal is to build a clock–but before I start building a clock I need to learn how to use the tools.

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