What would some one use this tool for ?

This came with my small lathe. One of the few that show signs of rust.

The ball races on the arms are spring loaded towards the 2 that are solidly mounted at each end. Stiff wire springs. The same size and type used on the pin on the dividing attachment that came with the laths so probably made by the same person.

I suppose it could be used to test for straightness or even roundness. The DTI reads to 1/10,000", it still works well too.

John

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I'm sure you're on the right track, John ...

It could, conceivably be for setting the cutter on a between-centres boring bar; but then it would make more sense to have centres.

MichaelG.

I dont know about you but the fact that the clock is positioned upright to the fence indicates to me that it may have been used as a simple depth clock/comparitor of sorts, quite probably for measuring roundness like you said if it has the ball races going across it.

Specialist depthing fixtures to buy from the measuring companies from the likes of mitutoyo even today can set you back a few hundred quid. But the dial gauge is the important bit and it's feasible someone may have made a simple fixture to meet that need a long time ago.

Michael W

Its definitely a concentricity gauge, ive seen similar homemade ones used for bullet shell cases., though this looks bigger and probably just for round turned projects. I had a similar but different device which came with a wartime Pultra lathe i have .

Edited By mark smith 20 on 18/10/2016 23:55:18

could it be for checking or straiten rod or bar stock. place bar in bearings and turn.

It could have been made to measure the straightness of arrows.

Graham, I think has it. I have a professionally made version for the purpose of arrow straightening and it is essentially the same.

Or straightening clock arbors.?

I don't think it was made in a home workshop. The main body is 1" x 1/4" and bent too well for that. The Comet brand small tools were introduced in 1937. No info on when it ceased other than a company name change in the mid 60's.

I would have thought that the person who sold me the lathe would have known if the previous owner had an interest in archery. He was interested in clocks. No info on the owner before that but he was alive when he sold the lathe so probably just sold that on with it's bits and pieces.

The problem I am having is what use is it in a home workshop. The parts need to be at least 6" long but I suppose small things could be fitted to a mandrel but the position of the dti limits their size. Realistically I doubt of they can be more than 3/8" dia.

It does sound like it's vaguely arrow related. I did have a bow, arrows and target when rather young. Wooden shafts and somewhat larger diameter shafts than modern ones. A fairly powerful thing - American Indian style. It came from a sports rather than toy shop. I've no idea when metal shafts were first used. Or compound bows.

John

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Edited By Ajohnw on 19/10/2016 10:10:45

I used to practise kyudo (japanese archery) and used aluminium arrows as the bamboo ones were too expensive. They were always getting bent, particularly if I missed the target and hit the wall .

I used a pair of v-blocks and a drill press to straighten them by eye. John's tool would have been much better.

Russell.

Maybe I should sell it as a rare vintage high precision arrow straightener.

John

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http://www.ebay.co.uk/itm/Arten-Arrowsett-arrow-straightener-/122062884256?hash=item1c6b83cda0%3Ag%3AaZ0AAOSwENxXmkq2&nma=true&si=X7Sg%252FtPXLwpPF9zngwdoj4ojn%252BA%253D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557

A newer version, sold on epay reentlly. An 'unused' one fetched £76 since.