My experience with the 16 bridle joints, open mortice and tenons, or whatever they are called on my windows:
- Initially i thought my saw was poorly set and was drifting in the cut. However it turned out to be my skills (poor workman and tools etc). By about joint 12 I found a relaxed feeling whereby once I'd cut a vertical saw kerf I could allow the saw to fall forwards and everything would end up square. I knew instantly when my technique was off as the saw would not move easily in the cut, I learnt to stop, think and go again as it would only get worse if I carried on regardless.
- I improved cutting waste closer to the knife line. By the end i could get to within less than a mm of the line, initially I was having to stay 1-2mm from the line to ensure i didn't impinge on the line by the end of the cut. Strong linkage to point above.
- I was never confident enough to split the remaining waste away, i'm with sploo and did lots of creeping up on the line. I did notice that as my paring skills improved i could take heavier 'parings' a could control the chisel to keep the paring of an equal thickness.
- Chisel sharpness is king in all of this, I would touch-up the edge as soon as paring stared to split not cut the waste away.
- At the start I could get roughly one joint cut in an evening in the shed (yes about 3hours for 1 mortice and 1 tenon)*, on the last window I managed all four corners in one session (about 4hrs+), so i'd sped up considerably. Speeding up was better marking out, knifing, cutting out the waste, paring to the line, etc etc.
Regards
Fitz.
*joints have dissimilar length shoulders to take account of the window rebate, and shoulders on some tenons are sloped to account for the angle on the cill. That's my excuse for why i'm so slow and I'm sticking to it!