Here's another mini-mortar I just made, again using only a cordless drill, files and sandpaper.
This one is a bit bigger than the last one- it's made from 1/2" 1018, and is .31 caliber, with a reduced powder chamber of just over 4mm (sorry, I'm mostly metric...)
Since the chuck of my drill is 3/8", I drilled the bore, and then epoxied a piece of cut off bolt into the bore as a mandrel.
I was then able to chuck it up in the drill and turn the outside of the barrel.
When I had finished I simply applied a bit of heat, and the epoxy let go.
The trunnion bar was turned from a nail, and is a press fit in a bump I left on the rear of the tube. I wish I had made it a bit wider, but enlarging the hole would have meant breaking the 1/3 rule at the powder chamber.
Touch hole is 1/16", but looks a bit wider in the photos because I gave it a slight countersink to get rid of the rough edges.
I finished it by browning it with Birchwood Casey Plum Brown, and then boiling it in water to blacken it.
'fonly I had a lathe
