Just a quick post - a DIY Arai Drum Brake Tool. It is basically a giant pin wrench. This only works on original, unmodified Arai Drums with the fins.
Your materials are 2 - 3" long 3/8" carriage bolt, nut and washer, and about a 4 foot long length of 2" x 4" lumber. Your tools are a 3/8" or 3/4" drill bit and electric drill, and a wrench for the carriage bolts.
On the wide side of the 2x4, drill your first hole (3/8" for bolt axle, 3/4" for QR axle) 5 inches from one end completely though the 2x4. This is the axle "pilot" hole, which keeps the tool stable while removing the drum.
Then drill two 3/8" holes for the "pins", 2 3/4" (center to center) from the axle hole, completely though the 2x4.
Insert the carriage bolts, and make sure the are tight. You don't want them to wobble in use. This other reason I use a 2x4 rather than any light lumber.
With the wheel removed from the bike, and all the hardware removed from the drum side (remember the washer order for your bike), slide the carriage bolt pins into the holes in the fin. Make sure you are not hooking any spokes; you may need to add a washer to the "head"side of the carriage bolt to keep the pins out of the spokes.
I don't have time for an in-use picture; with the wheel against your body and the brake out, you pull the tool from left to right.