Acoustic Guitar Construction

For an A-frame instrument I'm building, I need to cut angled slots in the headblock for the two long A braces that run the length of the instrument.
The slot need to fit a 5/16" x 3/4" brace, at the angle approximately as shown.
Not sure how to do it. Got ideas?

Saw the sides of the pocket to depth, rout out between the saw lines and then use a sharp chisel for the ends. Never done it so there's probably a better way.

I think that'll work, Tim, thanks. If anyone has another method to add to this one, let us know.

The traditional way would be to chisel them out just as you would when making a mortice.
A router, guide bush and template would be the modern way, but by the time you've set up the router and made the templates, you could have chiselled out 10 of these pockets by hand.

Bob

It seems that Tim and Bob have chisels in common. I think I'll lead with a hand saw, then chisel out the mortise. At my rate of 'production' - what a laugh - setting up the router probably is not worth the time this time. Maybe I will post a picture of the results. Maybe..:-)

Yep -- fret/razor saw and sharp chisel. You could make it a little easier to remove the waste material by drilling those holes to depth and adding a couple more drill holes -- shave out what remains with the chisel.

Those holes are for something, I guess, they came with the block , but I won't be using them for their intended purpose so why not take advantage? I like the ideas.