Hi Brad,
That picture is quite informative and as you will probably already know the methods employed to fix wall posts to crucks blades is many and varied.
I have inserted a digi pic above of the skewed square pegs employed at the top joint between a truncated cruck blade and half lap collar. You will note that bark can still be seen on the outside face of the cruck blade and a profiled make up piece has been added and then a large packer on top of that to align the side purlins from cross frame to cross frame. You can see how the purlin has twisted or rotated in its 600 years of service life. The black on the elm timbers is from the original open hall fire smoke.
The second picture is of the same cruck blade but taken from the opposite side and from lower down - about 4 feet from the ground floor. The cruck blade is painted. The drilled hole that is seen to emerge from the side of the cruck blade has been made using some kind of spoon bit auger (Jim, please add any comments and / or advice on the tool employed please). It demonstrates that the long pegs used to secure the cruck wall post to the back of the cruck blade (i.e. as per your photo above) were also set on the skew but the pegs did not reach right through the blade and appear to have stopped short. I think that the end of the peg can just be seen about to emerge on the left.
One does see a mixture of both mortice & tenon, lap and simple skew peg attachment of components in the same cruck frame and thus these joint selection decisions are obviously made by the carpenter based on the materials to hand.
Our recording team get quite excited by the relative simplicity of the design of the cruck frame being recorded and quite a few of them suggested that we build our own cruck frame. I have a woodlot that stands idle most of the time so all we need is someone to fell the trees, hew out the blades, cut the frame and raise it. Anyone who is keen to have a go please get in touch - no money required.
Regards
Ken Hume
p.s. we found almost no evidence of piece marking of timbers but plenty of hewing and framing leveling stations.