In The Workshop

The Bizarre Lathe I Use

Many folks have asked for a little more detail about the lathe I use for turning the block rims I make. You can see a couple of pictures on this page, and then you can look at a Adobe Acrobat page with some more pics and details.

Before building this contraption I was anticipating eventually buying a large metal working lathe to precision turn my rims. Such lathes, however, are big and very heavy, not to mention expensive. I decided to try and come up with something to solve my short term problem, while giving me the precision I wanted on the cheap. Although I keep thinking I ought to take some time and clean up the looks of this thing, I haven't, which allows you to clearly see the evolution of the idea. So, pardon the clunky on-the-fly design and read on.

In short: The lathe is based on an old, heavy duty Shimpo* potter's wheel, which provides a 12" horizontal faceplate of solid, very true cast aluminum. By using masonite "bats" and bat pins to hold them in place (standard potter's fair), the lathe also serves as an excellent 12" horizontal disk sander and I can rapidly switch abrasive grades just by pulling off one bat and dropping on another. For rim turning purposes, the "bat" is a special one bolted to the faceplate and has a turned 1/2 ply round screwed to it. This round was turned in place to fit the interior of my rims with a very snug interference fit. In lathe terminology, this is a chuck, and it (having been turned in place) automatically centers the work.

By looking at the detail sheet, you can see that the rail the holds the tool mechanism spans the entire diameter of the faceplate plus enough to slide in the rail holders. This allows me to lift the entire mechanism up and drop it into the inside of the rim once I'm finished turning the outside and do cleanup work in the inside.

This whole thing is actually a pleasure to use. The cutters (made for metal working) peel off lovely, long wood shavings. So long as cuts are taken gradually, there is no chatter at all, and the blade remains rock steady on the work.

*This wheel is also the basis of the assembly I use to accurately fit neck heels to the pot. It's become a sort of banjo Shopsmith for me. Such wheels can be had used for around $400 - $500 and feature a mechanical variable speed mechanism, giving them good low speed torque.

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Detail of the cutter at work:

 

A specially ground tool cuts a cove for the 1/4" brass ring to fit into.