This is the 18th post in this series about the construction of a complex 19th century French sawhorse, by Mazerolle. The study of the braces connections to legs rotated in various ways serves as a vehicle for some types of roof carpentry.
The last set of mortises for the faces aplomb legs were the blind mortises, which, like the other mortises in these two legs, are oriented roughly along the diagonal axis of the leg. In the text, no mortises are indicated at these positions, and due to their difficulty of cut out, I suspect that the braces were simply spiked in position at these spots. It’s not possible to use a through-mortise at these lower brace locations as the long side braces overlap the exit locations and their tenons would partially interfere.
I figured I could form mortises with the aid of a jig. So, I figured out the geometry of a jig block, and here is the rough-cut piece:
As far as mortising goes I’m done with those two legs. That leaves the remaining pair of legs, each of which is unique, since their rotations relative to the plan are each unique. That means eight more mortises and I’m, er, through. Fortunately, both of the remaining legs are aligned to one or the other x-y orthogonal axes of the plan, and that means that the mortising for those pieces will be more or less normal to the faces of the pieces, unlike the obliquely-oriented mortises just done for the faces aplomb legs. I’ll have to go back to the drawing and carefully work out- again – the positions of the mortises on the legs and the slopes of the upper and lower walls. I do this again, because the more I practice the drawing method, the more it soaks into my thick skull.
Thanks for swinging by today! –> Go to post XIX