I've done a couple of sets for two of my older O/U's. One was a Yildiz 20 ga, the other was a Lanber IGUN.
With nothing but a drill press...a dremel....small files and 3 or 4 grades of emery cloth...60, 120,220-400 and a micrometer.
I'm a semi pack rat ( my opinion...NOT my wifes...lol)...I found some nice steel rods in old printers !!...some are thiscloseto the actual size needed. They worked magnificently. Good and hard too!
The original pin on the Yildiz broke after about 1000 rds of Sporting clays...the replaced pins I made stayed in the gun for the next two years. They were still in it when I traded it in.
Same thing with the old Lanber. the homemade Pins lasted longer than the old original ones, and were also still functioning when the gun was traded.
I fudged up a couple trying to get there too quickly. Once I got my patients back, it wasn't too awfully hard.