best way to make a 45 degree mortise?

[Tom L]

I've been looking at hollow chisel mortise machines. at best you can buy a machine that will tilt 35 degrees.
and I think I understand why. the drill is at such a sharp angle to the workpiece. that it would be difficult to keep everything straight in a 45 degree mortise . and would be at such an angle that things just don't work out with the chisel and the angle.

so how does everyone make a 45 degree mortise for a typical knee brace where you want to use a mortise and tenon joint?

[Brian_Weekley]

No need to angle the mortise. You just cut it 90 degrees to the beam (it's OK that the mortise is larger than the tenon on the non-bearing side).

[Tom L]

thanks brian

I did think of that , but I thought taking the wood grain at a different direction would make it weaker.

but now looking at your sketch it makes sense that it is running in the same direction