Domino Dilemma aka is this joint possible with a Domino...?

[Stevenski]

I am sure there is a way to do it but as a total novice to the Domino, it has me beat at the moment. Can someone help? Please?

I am making a newer version of this shelf system in plain pine and have decided to use dominos for the first time to obtain invisible joints.



Since this my first project using dominos I have started with a mock up of all the individual joints to get my bearings before going 1:1
I started with one of the main frame modules



So far so good but now I have hit my first brick wall. I simply cannot figure out the correct positioning and references for attaching the horizontal stretchers to the vertical frame
The joint I am trying to achieve is shown in the yellow circle. I've stuck some blue tape to show what I am using as my reference face.





My problem is how on earth do I cut the mortice in the dark blue circle so that it will match with the mortice in the yellow circle?
I simply cannot figure out how to set up and position the domino machine on the slat to make the cut and get a matching hole



I'm feeling a bit stupid at the moment and am sure I am not seeing something that is probably blindingly obvious but that's where I am. Confused

The only thing that I can think of at the moment is that I will have to reference these mortices from the other side ot the vertical frame but that can't be right surely...?

Could an experienced "Dominator" help me out here?



Thanks in advance and sorry for the long post but hopefully it illustrates my problem

 

[MacBoy]

You are on the right track with your postulation.

The reference face has to be the underside of that horizontal member.

The other reference face has to be the bottom of the vertical member.

Then the depths of the mortises will be the same, as measured from the ground-to-the-sky.

The Domino’s Fence (the one that can angle) sits on those reference faces.

 

[Crazyraceguy]

That last pic is easy, you are very close. You just need another line, to reference, since you can't see the line you are trying to cut. That second line needs to be 10mm below the other.
The main thing to be aware of is not to get ahead of yourself. Be sure of all of your joinery, before you glue anything together. You can end up with an assembly where there isn't enough clearance to get the DF500 into.