Unfortunately, they stopped making the Lee Loader hand-loading kit for 12g at some point, much to my (and others) annoyance. They still make them for rifle and handgun, but not for shotshells.
I've seen people using them on youtube videos, and I've seen a few for sale on ebay, but they're becoming rare and the prices are going up (plus I have postage to deal with, because I live in Atlantis, aka Australia).
So I thought I'd just build my own kit.
Most of the parts are easy enough to put together. A wooden dowel, a quarter inch bolt, a block of wood with a washer on it and a hole drilled through or even a stack of washers glued together (for de-priming), a flat surface (piece of steel or hardwood). I use cut-down brass of various calibres as powder measures, and I load black powder for my old 1890 double barrel hammer gun, so I'll be running a square load (same volume of powder as shot) - so that's just one measure, which is a bonus.
The last bit is the crimper. I can see from the pictures it's a steel tube, and the dowel (sized to fit inside the shell) fits down inside one end to finish the crimp, but it also starts the crimp... I assume it has a cone-shaped inside to do that?
Anyone got any ideas how to replicate that?
Do you have the 12g Lee Loader and you can take a pic of the inside of the crimping tool?