Vices: Part 1 – double screw leg vice

Vices: Part 1 – double screw leg vice

The modular nature of the Moravian workbench was one of the many reasons I built this bench. If I don’t like the tool tray I can replace it with a flat board flush with the bench top. Don’t like the position of the vice screw? It’s not through the leg so I can change the back piece without messing up the rest of the bench. I’ve built two sets of legs so that I can have a taller carving bench and a shorter joinery bench.

AC528B6F-B022-4241-8C88-478F88AD01F2It’s given me the opportunity to play with a couple of ideas. Two years ago I saw one of Douglas Coates’ Ad-Vices at Oliver Sparks’ ’shop. Earlier this summer I got to examine it in a bit more detail and take some photographs. It has a clever double screw mechanism. Instead of a parallel guide at the bottom with holes and a pin it uses a threaded rod with a nut between the vice chop and the back piece. This keeps the chop parallel to the front plane of the bench.

Building one into my new bench been a rather lengthy diversion from all of the other projects I’ve got planned and I’m not sure it’s a huge improvement over the traditional guide but it’s an interesting feature. The Ad-Vice has a greater distance between the small, lower screw and the large, upper screw than between the workpiece to be clamped and the upper screw. This gives it a lot of mechanical advantage and means that the smaller threads of the lower screw aren’t under so much pressure. I couldn’t achieve this ratio and it will be interesting to see how long the lower screw lasts. If it breaks I’ll just replace a couple of components – the joys of a modular workbench.

I’ve also built an end vice, but more on that next time.

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