What saw for cutting the birdsmouth where a rafter meets a wall plate ?

I’m going to start on the timber frame for my bungalow soon.
When I get to the roof I’m going to need to cut the rafters where they meet the wall plate, like this…

I was thinking a sliding compound mitre saw would be the tool for the job, something like this…

However, it only cuts bevels up to 48 degrees left, 5 degrees right, which seems fairly typical for that type of saw.

I haven’t worked out the roof pitch yet, but say it’s 30 degrees, that means I need a 60 degree bevel cut.
Is there any sort of DIY power saw that will do this ?
I’m guessing the answer is no, because as the angle gets flatter, the cut gets deeper, so the blade needs to get bigger.
I can’t see any easy way of doing it with a router and a band saw would need some sort of sliding table, so it looks like I’ll be cutting them by hand then ?

Use the mitre saw (or line all the joists up side by side and cut across them with a circ saw) to cut the shallow angled side of the notch. Then make a few more cuts at the same angle, but at less depth, down to the line you want to cut the other side of the notch along. then finish off with a chisel. If you place those additional cuts well then they make it easy to see where to chisel down to.

I use a circular saw for every cut on a roof apart from the birdsmouth, for these I always use a hand saw (Spear and Jackson preditor).
Do not use a mitre saw for roofing cuts ever! HTH.

maccruiskeen, yeah, I’d worked out I could do one of the cuts. Making a few smaller cuts then chiseling the waste out probably would be easier than hand sawing it.

slimraybob, what’s the problem with mitre saws for roofing cuts ? I’d have thought for a novice like me it would guarantee getting all the angles the same.

Exactly what slimraybob said, even down to the spear and jackson preditor

Making a few smaller cuts then chiseling the waste out probably would be easier than hand sawing it.

A handsaw every time. If you’ve got an aversion to using a handsaw, then wtf are you doing carpentry ?

You could use a jigsaw if you don’t mind your cuts being on the piss.

roddi18, why though ? What’s wrong with a mitre saw for roofing cuts ?

Ernie, I’m doing carpentry because my house is falling down.

a nice new sharp handsaw

Nothing wrong with using a mitre saw, they’re ok for plumb cuts (where the rafter joins the ridge) but not much good for anything else, also you can’t just chuck one one the roof to make small adjustment cuts. My best advice would be to invest in a Stanley quick square and a good handsaw.
Birdsmouth cuts are pretty easy once you work out the seat cut(the cut that ‘sits’ on the wall pate) and the plumb cut angles.
E mail me with the width of you building and height of the roof and I’ll work them out for you.

Thanks for the offer. I haven’t got any plans, I’m making it up as I go along, so I don’t know what the exact width and height will be yet.
I’m not even sure if I’m going to make trusses or use purlins and rafters with tie beams.

Use and handsaw but buy a really nice one and put it back in its cardboard sleeve after each time you use it. I think most people’s horror of handsaws comes from using wobbly cheapies. A really nice one is a joy to use. It’s always handy to have a cooking version and a shagging version of things like chisels, saws, etc.