In order to cut Scarf joints accurately, I made up a jig to hold planks of up to 230mm wide by 22mm thick. This was used to join the long lengths required for the Keelson and the Stringers.
The jig consists of a framework which holds the work at the correct angle for a Scarf joint - giving the required 10x the thickness of the timber for the length of the joint. On top of this is a sliding platform which slides along the length of the jig - for the length of the joint - onto which the router fits and slides from side to side.
Once it is set up it is just a matter of sliding the router from side to side whilst moving along the length of the joint. In order not to put strain on the router the depth is varied in increments.
