Door Rail Length - Then The Doors Mortising
BEFORE we can cut ALL the door rails' MORTISES, we have to cut ALL the rails (there are 10 of them) to their FINAL LENGTH. If we'd cut the mortises first, then trimmed the rails to Final Length the stock Dominos we're using would be a too long - and none of the joints would close completely. THAT' would be a NO NO! We could shorten all TWENTY Dominos to fix that problem but THAT would be a real PITA. So FIRST we get the rail length thing right - THEN we cut the mortises -in the doors' rails and stiles.
In furniture making it's always best to ASSUME NOTHING and as much as possible Keep It Simple Stupid! (aka K.I.S.S.). SO - with the hinges we're using placed on the front frame of the cabinet we can butt the actuall hinge side" door stiles against them as they'll be in the finished cabinet. We can then find the center between the insides of the "hinge side door stiles" and place the "indside door stiles" in position - on Centerline. THEN we can get CLOSE to the FINAL length of the rails. Using Slip Sticks between a "hinge side" stile and an "inside stile" we can get a rough length of the rails - rough meaning a little over 1/16ht in longer. We'll only cut two door rails to this length.
Here's why we need TWO test door rails.
Place the RIGHT DOOR's Test Door Rail 2 in its frame position, with the frame butted up against its hinges, Place the LEFAT DOOR's "hinge side stile" against its hinges, butt its "inside stile" angainst the right door's inside stile - then see how much Rail 1 overlaps (see below for the graphic verssion of all that).
Note that the OVERLAP IS TWICE WHAT WE NEED TO REMOVE FROM EACH DOOR RAIL. Read that again. Our rails are cut to be a tad oversized. So by doing what's shown above, we've moved the door parts off the opening's centerline - by the OVERLAP amount. To move the doors' centerline back to the opening's centerline - we have to take HALF the Overlap off of each rail. Read that again until you understand it.
Here's how we got the rails to Close Length AND how we fine tuned the fit.
Once all the door rails' lengths were cut so that BOTH pairs of doors closed flush against each other it was FINALLY time to cut the mortises for joining them to their rails. That's FORTY mortises to cut - and they have to be centered on the groove for the panels. Be off just a little and the grooves won't line up. If the grooves don't line up the panel won't fit - and THAT would be a bummer! Twenty mortises in the side grain of the stiles and 20 mortises in the end grain of the rails