Bird’s Mouth Jig Much More Complex Than Originally Thought

This afternoon, we tackled the next tool and template we will need for the production of our roof rafters and this time, it was the Bird’s Mouth jig template. We thought we could use the jigsaw machine to give us the means of quickly cutting the two straight sides of the “notch” at the bottom of the 89mm CLS timber. But our tests revealed that the jigsaw does NOT like being guided by an external straight edge, it kept wanting to curve towards the guide edge and bending the blade! it seems that jigsaws works best free form, meaning that one has to follow the line by eye, rather than the whole machine being guided by something else. it was quiet annoying to realise this!
Next, we tried using a router with a long straight cutter bit but the piece of our timber we are trying to cut is 38mm thick and it proved too hard for the router machine to cope with it all! Phew! Finally, we looked at using a circular saw! But, even though it cuts a lovely straight line, the machine itself is not very symmetrical and would have meant a very complicated template with moving flaps to make it work properly!!
That brought us to the end of the day and we abandon that task as well!!
Tomorrow, we will tackle this problem again and probably end up with a simple jig to guide a hand saw and we will have to do the job of making over 200 Bird Mouth notches by muscle power alone! Phew!