My uncle told me to always use a framing square for layout, not a speed square

He said it was more accurate, but I thought he was just old school. Last month I was laying out rafters for a shed roof and used my speed square like always. Cut all 12 pairs, went to put them up, and every single birdsmouth was off by about an eighth. Spent half a day fixing them. So, what's your go-to for rafter layout? Is the framing square really the only way?

3 comments

3 Comments

the_grant1mo ago

Check both tools against a known 90 first.

rosek441mo ago

Yeah, the_grant's right about checking them. I've had a speed square drift on me before (it's a real pain when you find out after the cuts).

the_elliot21d ago

Totally thought checking was overkill until a bad angle ruined a whole batch of trim. Now it's the first thing I do.