24 January 2013

Figment of my imagination

After seeing the portable workbench (just the top part on the picture) from Jonas Jensen presented by Chris Schwarz,

I thought the vise at the right looks similar to the one used at l'atelier Boulle for tenon cutting, a boite à tenon to be used with a horizontal saw (scie à enraser).

So,  is the workbench related to the tenon box?  To justify this I have to find a meaning to the left part of the portable workbench - tenon box

What about the long vise,  is it for making long tenons?
.... Exactly.  Long tenons are uncommon for frames, but in beds the front and back frame is joined with two boards and these use a tenon and a metal screw to make it possible to assemble disassemble the beds.

Bed details as seen by Roubo in l'art du menuisier

The real thing with a 50cm (20") wide board of a bed side with tenon,  that's a close fit for the Jonas Jensen bench.

I see,  but the benchdogs on the workbench, what's their use?
I am glad you asked, .... that .... it's for  .... rip cutting the tenon.  This is normally done with a frame saw,  but here the tenon is too long.  A back saw could do it,  but that's uncommon in some workshops.  So the sides are set flat on the frame and a mobile surface is clamped in the long vice, set level with the sides of the tenon and cut with the same saw.

Cross section of the saw raised to the correct height for a horizontal cut of the tenon.

So, a bed-maker-tenon-cutting-jig?
Maybe for some and it became a portable workbench for others.
That or it's simply a workbench that is just so good it can even be used as a boite à tenons.

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