Re: Re: Engraving and engine turning

Ian Wright wrote:

<My little machine will have a Z axis exactly like the X and Y axes but
will have weights on strings over pulleys to balance the weight of the
cutter head.

Ian>

Another solution is to use a "Tensator " spring, like a clock spring,
pulling up the quill, not fixed to the downfeed spindle. This is wound up to
counterbalance the weight of the quill and give you some preload against the
downfeed gears. Over the travel of the quill it will exert a constant force
like the weight but it takes up less room. There was an article by
G.F.A.M.Turner in Model Engineer of 20th January 1989 describing this system
as a modification to a Far Eastern mill/drill. I used it successfully on a
small home made mill but I haven't yet got round to adding it to my latest
machine.

Pete Jarman
North of Bedford, England