The last matter to deal with on this project is the fitting of the sacrificial cap. I managed to obtain a nice piece of vertical grain Fir from the architectural millwork shop down the street, for $6. Price was right! I wanted something a bit softer than the Canarywood, a material that would not be too slippery in surface quality, and the Fir fit the bill perfectly.
I made up a MDF jig to rough out the sliding dovetail mortises, of which there are 6 in total to be cut in the top and cap:
A few steps later, the mortises were roughed out:
Then a little chisel work to square up the drop in sections – here on the Fir cap:
A run in with a dovetail bit and a little more chisel work and the mortises were complete:
Then I made up the double dovetail keys in a scrap piece of white oak, and checked the fit of the keys:
The fit was acceptable, so I glued them in place.
Next, I started cutting the trench for the locking pin:
I checked the pin against the trench to see how it fit:
Next, I installed the cap, slid it forward and transferred marks from the beam to the cap:
The trenched parts complete:
Install – the parallelogram shaped pin is Honduran Mahogany, which is about half-way in between the hardness of the Fir and the Canarywood:
Peek-a-boo out the other side:
Last step was to clean up the cap with a few planing passes and some chamfering:
Here it is, at last all done and ready for use:
The other side:
For the near term, I’ll leave the fixing pin a bit long, and then run it in and out a few times before trimming it flush at some future point. The cap is also slightly proud of the beam to act as a bit of a bumper to keep the beam underneath it in better shape longer (I hope).
All in all it came out well, though not all the fits are as nice as I would like them due to an error in the glue-up process. The main point was to learn a layout method which would apply to roof carpentry, and in that respect it has been a very worthwhile undertaking. The sawhorse should last a while – I wonder how much weight it can take? I won’t be doing any destruction testing though, hah-hah!
Thanks for dropping by today. I wonder what I’ll find to write about next time?