[Shop-talk] Notching rafters for purlins?

[Chris Kantarjiev]

I guess it depends on how clean you want the cuts/channels.

I often build shelves out of 2x4s, and I notch the uprights to hold the 
crosspieces. All I do is set my circular saw to 2x4 depth, cut either end of the 
notch and whack with a hammer. The bottom won't be perfect, but it will be 
close, since it's breaking in parallel with the grain.

In my case, the shelf weight is supported on one of the cut edges, which is 
straight. For purlins, that's not going to be (entirely) true.