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Discussion in 'Horological Tools' started by Curt Lefferts, Sep 27, 2019.
I am in need of a bow for a set of Turns. Does anyone know of a source?
for my education - what is this "bow" and what are "a set of turns" ?? I am not familiar with this terminology
I made a bow for my Jacot tool, just a conveniently sized piece of rod bent into a bow shape, with a stout thread from the sewing machine box. I think it was Nylon, meant for buttons etc. I tried various things including dental floss (it breaks up). I'm pretty happy with the thread.
I suppose turns might need a stronger bow, but still I bet it might be a thing you make instead of buy?
The 'turns' is a dead-centre lathe, which was the predecessor of all powered lathes, and it was powered by a bow acting on a driver pulley, either clamped to the work piece or as in the pictures below, a loose pulley with a driving pin. Later they were also driven with a hand-wheel or foot treadle. It still has its uses, especially for turning balance staffs and other items which have be perfectly concentric, because you can take the work out to measure or check it and put it back umpteen times and still maintain concentricity, which isn't guaranteed when using collets.
The larger sizes for clock work were known as 'throws'.
Curt will probably have to make a bow himself; I use some stiff steel wire with fine fishing line for the string. Hair from a horse's tail used to be used, but I found it rather fragile when I tried it.
A set of Turns is a manual driven watchmakers lathe. It is used in very fine hand work in which the feel or touch is important. It is driven by a bow. The bow is an arched frame that carries a string that is used in one hand to provide power to the lathe.
Thanks for the assist Grahm - well said. I do not have a set of throws. Dave from Daves Watch Parts actually had a bow for me
Thanks so much Gmorse -
I figured that the bow was as described, but had never heard of the "pulleys" being called "turns". I have an old unmounted hand drill that is bow driven. Now I know what the proper term for the "pulley" is.
The whole lathe is called the 'turns', the pulley is just a pulley, (although of course it turns!). I know it may jar grammatically to call it 'a turns' . . .