For those not familiar, inner drum radius and brake shoe radius rarely match until the shoes are worn in and that can take a LONG time especially on front drums.

First video shows enough of the cool custom machine to copy. An electric die grinder or router motor would make plenty of power.

Second shows a theory of operation and (important) radius setting adjustment using an AMMCO grinder.

Grinding went out of fashion decades ago because of asbestos dust but it's the only way to match shoe and drum radius for maximum contact. I'd do it outdoors with a blower etc. behind me.

A pivoting clamp and a belt or drum sander/grinder could get it done. I'm into front discs myself but figure drum guys could use the info. I might make one for my Nortons but it won't be soon. I'll post if it happens.

You could also use a lathe with a tool post grinder but I wouldn't want the dust all over my shop.