The Most Difficult Timber Frame Tenon - Cutting a Tusk Tenon

Curious about timber frame joinery? Come along as I demonstrating cutting a tusk tenon for a floor joist.
This is the most difficult timber tenon on my project and a piece that is likely to fail if the joint is incorrect. This center floor joist features a tusk tenon on each end.
Tools used include: (affiliate links, I may earn a commission on qualifying purchases)
🪚 Japanese pull saw: amzn.to/3XQWKty
🪚 7 1/4" Skilsaw: amzn.to/3pI2sBf
🪚 Speed square: amzn.to/3Oa3b7s
🪚 Combination square: amzn.to/3XPI6T1
🪚 Carpenter's square: amzn.to/44EKQ7X
🪚 1.5" chisel: amzn.to/3NRW02J
🪚 3" slick chisel
🪚 Handmade wood mallet

[@philw245]

I remember cutting these out by hand as an apprentice carpenter back in the mid 70s.

[@appalachianwoodhomestead]

I’ve done tenons by hand…this is way easier

[@e2298sg]

What does this joint do? Or rather, what does it go into that it needs this shape?

[@appalachianwoodhomestead]

A tusk tenon is frequently used in timber framing when you need to connect horizontal timbers (such as in the floor or when attaching joists) without losing too much strength in either timber. The sloped shoulder helps increase the shear strength of of the tenon by increasing the surface area.