Thursday, November 10, 2016

Nana's Dining Chair Rebuild, Part 6: Some Details

I'm stoked!  Jazzed!  Chuffed (for our British friends)!!

At the end of the previous post, I asked for suggestions about how to add the recess details to the backrest panel and the front seat rail.
Detail work on the original chair
Thanks to the help I got from Ralph, Jonas and Bob, the job got done.  It took two days - one day to think about it and one day to do it - but the job is done.

Yesterday I tried a bunch of things in laying out the patterns.  For the seat rail, I started by drawing points exactly 5/8" up from the bottom, but not straight up - the points were perpendicular to the bottom at each point.  After connecting them with a curve, it didn't look quite right.
Experimenting on the template - not quite right
Then I realized that whoever made this chair originally used the exact same template to mark out the detail as they did for the rail's bottom edge.
A very close match
The original builder probably drew in the shape from the template and then freehanded a powered router with an 1/8" bit.  The small inconsistencies lead me to think it was freehanded.

So I drew the shape on my work piece with my template 5/8" up from the bottom.  Then made many marks 1/8" below that line and connected the points either freehand or with the help of some French curve templates.

For the backrest panel, I experimented with making a template based on the original chair.  I made a rub of the original to get the outline.
Made a rubbing of the original backrest splat
Close-up view
This worked nicely, but I realized that just as the original backrest panel was not symmetric, the detail that I'm trying to reproduce was also not symmetric.  So I ended up generating the curve myself.  I used a compass to scribe a "parallel" curve along the sides 5/8" in from the side.  At the bottom I had to adjust the setting of the compass to account for the tenon.  At the top I had to wing it.  After getting the corners to look right, I marked points 1/8" outside of this shape and connected the dots.
Generating the shape of the recess
Now it was time to knife the lines.  I experimented with making a twin blade cutter, but abandoned the idea.
Thought about making a double bladed cutter, the blades set just over 1/8" apart
I tried cutting freehand the lines for the front seat rail on a piece of scrap.  The freehand cutting was OK, but trying to chisel out the waste was horrible.
First attempt on scrap
This morning I bought a set of French curves, something I've thought about getting many times.  I needed something to guide my knife when cutting the outline of the details.
Using a plastic French curve to knife the lines
This worked well, but was slow as I really didn't want to mess up the parts at this stage.  With the lines knifed in, I needed some way to remove the waste accurately and to consistent depth.  Jonas had commented about making a mini router plane from a block of wood and a screw.  This got me to thinking and this morning I had an idea,

I took a squared-up 1 1/2" x 3" and marked, sawed, and planed a 45° angle on the end.  Then I marked a 1/8" slot on that face.
45° end on a 2x4 with 1/8" (strong) slot marked out
After sawing and chiseling out the waste, a 1/8" chisel fit in the slot so that the body of the chisel was proud of the surface by 1/16" or so.  Then I screwed another piece onto the angled face to lock the chisel in place.
One mini router plane, coming right up!
Side view
Close-up view of the chisel extending down below the base
I couldn't wait to try it, but first I had to chisel out some waste to leave a hump in the middle of the recess.
Chiseling out some waste first
And then - are you ready for this? - I started routing.
Routing out the recess
Holy crap, this was exciting!  And it worked extraordinarily well, though I had to take very small bites and many passes.
Look at the little curly shaving!
I ended up going about 3/32" deep and used a piece of sandpaper wrapped around a plastic card to clean up the recess a little.
Front seat rail done
Backrest panel done
Like I said - STOKED!!

BTW, does anybody know what this type of detail is called?


  1. WOW that is impressive!
    What a nice looking router plane you made for that job.

    I don't know what that type of detail is called, "square trench" perhaps.


    1. Thanks Jonas. And thanks for your inspiration in making the little router.

  2. Heh good job buddy! I was a bit skeptic about knifing the double line, but, you got it done right..


    Bob and Rudy

  3. Overall impressive work with all those curves, angles, carving etc.

    1. Thank you, Sylvain. I still find the curves challenging, but I'm getting better. And that's the main thing!