Unlike the joinery of a standard table, the joinery in an old antarctic exhibition sled allows movement. This is one of the things I learned when trying to make a replica of a world war one stretcher and transport device.
I will write more about the transporter replica later. For now I want to discuss one of the joints used in the replica’s construction, the joint I would later use in a coffee table experiment. The joint is a standard three way junction, with one vertical post and two horizontal posts meeting on top of it at a right angle to one another. Think the corner of a table, but the cross pieces are stacked on top of the leg.
I learned in Scouts how to tie two sticks at a right angle using a square lashing, but this construction adds that vertical piece to the puzzle.
Unfortunately, I didn’t have a lot to go on when I tried to build my replica. I had 4 or 5 decent photos of the WW1 transporter, and 2 photos of a sled made by the inventor of the transporter which had been used on one of Mawson’s antarctic exhibitions. I certainly didn’t have anything I could take apart, so there is quite a bit of guesswork in this construction, but I can say the final result was quite a success.
Here is what I surmised:
Firstly, the lashing is pretty similar to what I learned in Scouts with one exception. There is a hole bored through the vertical piece which allows it to be included in the lashing. When the raw hide strip wraps down over one side rather than wrapping around that cross piece it continues down through the hole in the vertical timber and back up over the top. (see below)
Other than that, the lashing process is exactly identical to a standard square lashing (as seen above).
This was evident from the images. Despite a leather sleeve being tied over the joint to protect the lashings, I could still see enough of the join to recognise the raw hide strip passing through the timber below.
I did a lot of research on traditional sledmaking techniques (which is a fascinating rabbit hole to go down, and I highly recommend it). It appears that a mortise and tenon style join is not all that uncommon in sled construction, combined with lashings of some sort.
So the join became clear. A tenon ran up through the timber above, and the lashing held it in place. The only remaining question was whether the tenon went through both pieces.
This is where I did the biggest piece of guesswork. Worsfold, the man who built the Transporter, needed to hastily produce many of these sleds for use on the battlefield. It makes sense to me that you can save on time and reduce wasted effort if you don’t try to have precise three way joints at multiple points across a single item. So I made my tenon only rise through the first piece, and let the second hold on purely through the lashing.
Because of the “free” top piece, it also makes this join an easy one for beginners to use in creating furniture structures. How square my coffee table was could be adjusted by retying the join after all the pieces were finished.
These sledmaking techniques were passed on to Worsfold from Inuit cultures in Canada. They are smart and simple, and also really visually pleasing.
(check out my short post about the other lashed mortise and tenon joint here)