The VM Chair Making Project IV

Posted by on Mar 14, 2015 in Blog | No Comments

Fitting chair back.

Having completed the fitting and shaping for the crest rail as described in my previous blog on the VM chair the main jobs left were the fitting and shaping of the arms and the back splats.

I had previously routed 8mm mortices in the backs for fitting the arms. I had made the mortices 20mm long so that I could use dominos for this joint. This is the only place where I used the domino jointer, I used it here as I thought it would make it easier to do the tricky scribing of the arm to the back profile if there was not a fixed tenon sticking out. There is a compound angle at the intersection of the arm and back, before using the domino jointer I cut the end of the arm at the splay angle on the table saw then used the jointer on the cut face, then I cut the vertical angle on the saw. This ensured that the line of the domino was continuous from the arm to the back.

Although the angles were right the joint did not meet because the face of the back is profiled to a slight curve. Malmsten did not resort to expediency when designing this chair! This joint would have been easier without the curved profile! The profiling was done with various inside ground curved chisels and straight chisels. I rubbed chalk on the curved face and offered the joint up with the domino located. Where the chalk transferred from the back face to the arm I removed wood (rather like using engineers blue) until the end mated well with the back.

With the arm fitted to the back I was able to drill the 10mm dowel hole for fitting to the front leg. I used a dowel point in the leg hole to find the location.

With fitting completed the arms could be shaped. They were rough cut to shape on the band saw then completed with spoke shaves.

With the chair still dry assembled the curve of the back splat could be determined. I knew more or less what I wanted from the prototype but wanted to tweak it just a little. Clamping a steel rule to the crest and lumbar rails allowed me to flex it to the required position then scribe this onto a board which was then used to create the former for laminating the back splats. The splats were formed from five 2mm thick laminations. The laminations cut on the band saw then tentatively run through the thicknesser, fortunately there was no rattling in the extraction ducting to indicate the lamination breaking up under the cutters.

The laminating was done in a bagpress.

To mortice the rails for the splat I made up a jig into which the rails could be clamped while the router was held vertical to the rail. The rails needed to be a tight fit into the jig to ensure no vibration while routing with a 10 mm pocket hole cutter.

I spent a long time over the shape across the face of the  splats, mocking up the shape a few times until I was happy with the result, but I’m still not sure they are right! I made a template of the final shape so I could get symmetry between the two pieces. They were cut out on the band saw then finished with spoke shave and chisel.

The last shaping job was the seat rails. Before shaping I drilled the inside of the rails for the “L” shaped nails needed for the Danish cord seat.

After a final clean up and sand and some tweaking around the joints the chair was ready for assembly. More on that and the seat weaving in my next blog on the VM chair project.

Thanks for following my VM Chair Project and a very big thank you to those of you who share my project with your friends (Hint: you can use the social sharing buttons just below these project pics – Thanks!)

IMG_7288_opt (1)IMG_7289_opt (1)IMG_7291 225
Face of back piece chalked to aid scribing to curve....... End of arm showing high spots highlighted.
Arms fitted ready for shaping.
Fitting chair back.Shaping mould on router tableThicknessing laminations.
Determining shape of back splats using steel rule clamped to back.
Shaping splat former on router table
Feeding 2mm saw cut lamination into thicknesser on a board.
IMG_7318_optrouting jig routing jig
Back splat on former just out of bag.Jig for routing tenons in crest and lumbar rails.Crest rail fitted in jig and ready for routing.

Update: Very pleased with how the first course went. You can read about it here:

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Thankyou, Chris.

 

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