Off center turning

Re: Off center turning *LINK*

Fred Holder

>Here is the text from an article I wrote that was published in More Woodturning:

This article, like many that I write was stimulated by a letter requesting help. I quote here the letter that came in while this issue was being prepared:

�I am seeking advice/tips/techniques on turning oval-shaped hammer handles etc. I wrote to Rex Haslip in New Zealand and although he has never done it, he �assured� me that if anyone in woodturning knew how it was done, you�d be the man.... How�s that for a setup?

�I assume the technique must involve off-setting the centers but I�m at a loss as to any measurements or calculations involved. As I told Rex, I�ve searched the net high and low for the answer and have never seen any drawing or description of the technique. Perhaps it is so

utterly simple, compared to the fancy bowls and vases I see displayed, that no one thinks its worth commenting on. But it must also be an old technique, classic turned hammer, axe and other tool handles have been around for generations.

�Don Porter, Florida�

I responded to Don with the following: Robert Sorby makes an eccentric chuck that enables you to turn oval spindles like hammer handles, but it costs over $200.00. Actually, you can�t really turn it oval without a special oval chuck, but you can do a reasonable approximation with the Sorby chuck and also with simple multi-center turning. I have a book on multi-center turning.

Unfortunately, they do not tell you how to turn an oval hammer handle in the book. I will attempt to explain the process, even though I�ve never actually turned a hammer handle, I have done a good deal of multi-center turning.

First you need to design the cross section at each end of the handle. You need to have a square blank of the proper size and a couple of inches longer than your handle. Without drawings, I�m not sure that I can explain how to determine where to put your multi-center holes.

Take the drawing of one of the cross sections and locate a center that will be halfway between the top and bottom of the oval and between the two sides. Take a compass and draw a circle about this that passes over, or through, the center of the top and bottom of the oval. Draw a horizontal line through the center point and place the compass on the side of the oval and mark a line on the center line opposite this side. Do the same for the other side. I believe this will mark the offset needed for that end of the handle. Repeat this operation for the other end. Then making sure your square block is large enough to accomodate this offset, mark off the exact centers at each end and draw a

horizontal line to layout your offset. Layout the center points and offset points on each end. Now, mount the block on the lathe and turn it round to the shape that you desire making sure that each end is of the diameter of the up and down dimension of your oval. Now. shift out to the offset points on one side and turn until you are almost halfway through at the top and bottom of the oval. Then, shift to the other set of offset points and do this again. You should have a near oval and a little sanding to blend it in should

make it very presentable.

Like I said, I haven�t made one, but this would be my approach to doing so. I hope it is clear. Graphically, it seems logical. This stirred my interest, so I had to find out if my instructions would really work. I went out to the shop and turned a handle out of dry Cherry. I turned on

the offsets until the turning on each side joined on a nice little ridge. I used a skew to be able to get the smoothest cut. Then, I returned it to original center and sanded with a strip of 150 grit sandpaper. It became oval quickly. The process that I had described for Don did work.


Fred Holders Domain Site

Re: Off center turning

GeeSeaWhy

>There's a bit about turning oval tool handles and other multi-axis and off-centre turning in Mike Darlow's book, Woodturning Methods.

Graeme

Re: Off center turning

norm

>I have a copy of Multi-center Woodturning by Ray Hopper (ISBN 0 946819 35 1). it has a chapter on oval handles.hope this helps.