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Old Nov 18, 2004, 02:38 PM
Graham Stabler is offline
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Sticky Shepherd
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Oxford/England
Joined May 2001
4,017 Posts
Billy, with these tiny gears it is nice to have some adjustability. Peter Frostick recommended this gear box style to me and I tried it out last night. The diagram is by Peter and shows a box he made for an M20 motor. The mesh can be adjusted with a tiny wedge or if you keep the pinion loose till the last minute by bending the wire (needs to be well attached) in the relevant direction until the mesh is good.

Mine is for a 4mm pager and is slightly different. Firstly my spur gear has a long tube in the middle that could be used directly as a bush, this however meant I had to use slightly thicker wire. Also because the 4mm pagers are delicate I opted to mount the motor in a small tube made from carbon braid. The wire was bent roughly to size, glued and then wrapped with a few tows for extra security. Teflon tube is used for bearings and pvc wire insulation for retainers. The new prop was just glued to the brass tube. There is a small plastic spacer behind it made by heating an pulling some plastic tube.

The box weighs 0.1g so I think it is a little heavy however I think it will pay for itself in efficiency and I want to see if this is so.

Graham
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