Establish reference face and edge, not final thickness. Mark with the usual "l" and "v" respectively.
I chose a 3/4" wide clamp, which ended up being a bit narrow
Rip the clamp
Joint the sawn edge and square it up
Use a mortise gage to mark the haunch groove and mortise locations
Use a mitre square to mark 45˚ bevel on one end of the clamp
Saw the mitre end
Clean up the saw cut with a paring chisel. I used the mitre jack, just because I can.
Mark the 45˚ mitre end on the desktop, again using the mitre square
Mark the full width of clamp (3/4"). Use a knife, and the line should only extend from the mitre to the free edge. If you extend past the mitre, you will regret it (DAMHIKT).
Saw the stop cut for the mitre using a fine backsaw.
OPTIONAL: Cut in shoulder with a wide chisel if you use a saw. I sawed the first one I did, using a backsaw, but the stopped cut is too much of a pain.
Use the same mortise gage to mark the tenons
Chop the tenon shoulders. I chop fat of the line, then clean the shoulder at the end with a wide chisel.
Pop the waste out with a chisel if it's fairly straight-grained.
Use a router plane if the grain is odd or when you get close to the mark (unless you're really good with the chisel). This requires that your top is of constant thickness, though!
Final adjustment with a crank-neck paring chisel.
Mark the haunch depth on the tenons. I think I used about 3/16" or so.
Lay out the tenon widths; I used a wide chisel as a quick width gage.
Saw tenons to the depth of the haunch.
Cut out waste between tenons with a coping saw, or chop if you prefer
Mark the final tenon length
Cut tenons to length. I used a coping saw, since the ends of the stub tenons aren't critical.
Final paring of the 45˚ bevel in the top.
Mark the mortise locations in the clamp.
Chop the mortises. Be careful not to go too deep, especially if your clamp is as narrow as mine. I used a 3/16" tenon, gaged off of this W. Butcher chisel.
Plough the groove for the haunch. I think I used a Stanley #46, since it already had the 3/16" iron in it.
Final test fitting. I had to do some paring of tenon and haunch to make things fit properly. The long crank-neck chisel is handy here.
Bore holes for the dowels, now that you have mortises located. Only go through the bottom wall of the mortise, though! Size your holes according to your dowels; I made a quickie dowel plate for these maple pins.
The hole nearest the mitre should be a snug fit. The others should be elongated to allow for expansion/contraction, though that's not much of an issue with this flatsawn maple.
After pinning, plane the clamps to thickness on the underside.
Show surface after final smoothing, or something.
Bottom surface, showing pins in the clamps.
Scraper and corn straw burnisher used for final cleanup on the clamps. Easy to go too far with the scraper.
Coat of BLO thinned 50% with turpentine. Shows off the bookmatched maple, though it isn't highly figured or anything.