Saturday, March 28, 2009

Irregular Situation VI

Today I'll wrap up my account of making an irregular sawhorse with a look at the final steps in completing the cap and assembling the structure. Last time, I showed how the sliding dovetail mortises were cut, and all that remained after that step was to fit in a locking mechanism. This is the same type of mechanism I used to secure the paneled top on the Vanity project described in a previous thread.

First I fit the Larch top into position, selected the location where the locking pin would be fitted and then made a mark to index both pieces:


Marks were then transferred across the face of both the cap and the beam, and the trenches were fully marked out. Then, out came the dozuki and I started the cut out:


These steps are identical for both the cap and the beam, so I'll only detail the steps for the cap. After the trench shoulder was crosscut, I used a chisel to remove most of the waste:



Then I fine-tuned it with a LN skewed corner cutting plane, a tool I have since lost somewhere in Kimberley B.C.:


The nearly completed trench in the cap, just another pass or two (done when the fixing pin gets fitted) are remaining:


What can't easily be seen in the above picture is that the shoulder of the trench does not run 90˚ across the surface - it is sloped inward a couple of degrees, as is it's partner on the beam. The shoulder cut, however, is 90˚, which means that the fixing pin is a tapered parallelogram.

Here's how the cap and beam come together then:


2:


And three, with the fixing pin started:


This is the completed sawhorse after assembly:


The short side, where the legs splay 3 in 10:


And the long side, where the legs splay 2.25 in 10:


This sawhorse was major layout triumph for me, and I consider it, in technical terms, an equal or better of any piece of furniture I have made to date. I know that may not be saying much, but I guess my point is that the world may be found in a teacup - the sawhorse is a great vehicle for layout study, and I felt a great sense of accomplishment to have figured out the layout for this structure.

This sawhorse has been put to plenty of use since I made it 4 years ago, and has proved it's strength and durability, holding well over 1000 lbs when moving a large lathe one time. I have left the mortise and tenon stretcher connections without pegging, wedging, or glue, and the construction holds together just fine. I have, alas, found the top with a saw blade on one occasion, and dropped a chunk of wood on it another time, so the cap has a couple of Yellow Cedar patches now. It's serving it's purpose well, in other words.

I am extremely thankful for the gentle pointers that Togashi-sensei provided me at the beginning of this study. When I completed the sawhorse, I sent him pictures and a small token of my thanks. He seemed pleased with what I had made, and asked me to send him my drawings, which I considered an honor.

1 comment:

  1. Hi Chris,
    Thanks for pointing me to this wonderful series of posts on the sawhorse. I had looked at all the titles of your posts to try and find it before I asked as I don't like to waste people's time by asking questions they have already answered. I am gobsmacked by what you can do.
    Cheers
    Andrew

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