Linkage Design

Catherine Marshall was a suffragist. The suffragists believed in campaigning for women’s votes through peaceful, polite┬ámeans. By contrast the suffragettes believed in deeds not words. In this model Catherine and a suffragette stand on either side of a donkey trying to get its attention with a carrot and a stick respectively.

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The women’s hands are moved via a cam and cam follower which in turn drives a linkage. I’ve used a heavy gauge wire to make the link. This part is made from a single wire bent into position over a template then fixed into position with a fine brass wire and some epoxy resin.link-01

A small screw fixed to a block on the box top provides a pivot point for the linkage.link-02

Then under the box the linkage is connected to a cam follower. All that remains is to see which is more persuasive; carrot or stick?link-03

Updated Rowlocks

I’m making a few mods to the Mary Chamber model to make sure that the rowing action is a full back and forth movement. First thing to change, the rowlocks. In the current version the oars sit in a simple fixed wooden U shaped cut out, I’m making a new version where the U shaped section is made from a sheet of shaped brass and is free to rotate allowing the oars more movement. The brass section is fixed to the boat, the steel section sits in the brass tube and is free to rotate. The U shaped section is screwed to the top of the steel section.rowlock08

I’ve cut the steel section from a 6mm diameter bolt. First things first, the steel in the bolt is hardened so it needs annealing. I heated it up to red heat with the blow torch.rowlock02I then let it cool down slowly in a bed of sand. I repeated that process a couple more times.

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Here’s the annealed bolt ready to go in the lathe. It will need the head rounding off then a suitable hole drilling and tapping. Finally it will need cutting to length

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Rounding off the head in the lathe.rowlock05

Drilling the centre hole.rowlock06

Tapping the hole ready for the screw.rowlock07

The completed piece ready to fit into the boat. One more to make for the other side of the boat.rowlock01