Inspired by a picture of a 'Bow Weighing Machine' made by Clarence N Hickman in 1938 I've made this machine
.
His one used rack and pinion gearing, but I don't have any real metal working facilities so I've geared it with pulleys.
It needs some fine tuning, return springs and such like. It also needs calibrating for length and weight.
I shall try and fit a nice black felt pen so the curve shows better and do a video once I've finished the detail (Hopefully tomorrow). The great thing is it works!
It's a treat to watch it work, the bow sting is hooked onto the back of the machine and the bow is pulled up by the handle, a thread is also hooked over handle and this is geared to pull the graph plate horizontally. A big spring from a spring balance is incorporated into the base and the stretch of this is geared onto the vertical slide where the pencil is spring mounted using a bit of hacksaw blade.
It's just 'designed' on the fly using stuff I had lying about, I've been thinking about this project for a few years and I've built it over the last few weeks.
http://s411.photobucket.com/albums/pp195/Del_the_Cat/websitevideos/?action=view¤t=fddemo-1.mp4Dunno if this is really the place to post it, but just wait for the video, it will make you smile.
Del