Harbord SP rig build 1

SP rig build-1This is the beginning of my build of Simon Harbord’s genius ‘Silly Putty’ (SP) AutoKAP rig. The dimensions are determined by either the part sizes or the jaw size of my vice. After reading up on the merits of hot and cold work I decided to cold bend the 25mm x 2mm aluminum strip.

Cutting the slot for the bottom end keyhole was by trial and error, I began with a 10mm hole (perhaps too big but it’s the same size as the hole for the top bearing) I kept widening the keyway it untill I got 25 turns on the band without it slipping.

I have chosen 6mm aluminiun rod for the spindle, this may not work as well as a flat strip but I have it to hand and it’s a good fit to the bearing. The hook is whittled away with needle files until the band fits without slipping.

My test rubber band is not ideal; it’s too long so it’s doubled over. I’ll hunt down a better fit in time. An ‘R’ clip secures the spindle.

The next problem is to find a way of taking the load off the rubber band, without a pin or bolt below the top bearing the entire weight of the camera is suspended by the rubber band. Not good. A tiny ‘R’ clip or split pin will do provided it’s not going to foul the spindle rotation, this is where I discover I only have 4mm clearance for the clip.

The camera mount is a cupboard door hinge, the idea being to develop a tilt drive at a later date, Pre-set tilt will be by either wedge and tape or nylon bolt.  A rubber band holds the hinge shut for now.

Next: suspension and then the famous silly putty!

Simons rig is demonstrated here

and here

B

About billboyheritagesurvey

Heritage worker
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