Help with angled joinery

[Roger Warford]

I am building a simple easel based loosely on plans I found on the internet. The end product should be roughly 5' 6" tall as shown below:

Easel.jpg

The sides form a right triangle with a 20 degree angle at the top.

Easel Side.jpg

As a skill building exercise I would like to use hidden joinery to join the side pieces. I think I should be able to cut tenons easily enough, but the mortises look challenging. Another possibility I've considered is making a jig to help align (perhaps three) dowel holes.

The best plan I've come up with so far to make a dowel jig would require drilling holes through the length of a 7 1/2" board, then crosscutting the board at 20 degrees to end up with a strip an inch or two wide that I could use as a guide for a hand held drill. I would think that approach would work if I am careful to reference the same edge on both boards (rather crudely illustrated below).

Easel Jig.jpg

Am I overthinking this? Is there a relatively easy way to cut the mortises? I generally find the most complex solutions first, so perhaps there is a much easier approach.

I am eager to learn and will be very grateful for any and all advice.

[Jamie Buxton]

I'd think about using a bridle joint. It is a perfectly legitimate joint, and it would be very strong in this application. It also happens to be pretty straightforward to make on a table saw.

[Doug Shepard]

I'd think about using a bridle joint.... .

My thoughts exactly.

[Roger Warford]

Thanks guys! Like I said - I always seem to go to the most complex solution first. Never even thought about a bridle joint, but that sounds like a winner!