Disc Pressing Die: Hardened Steel, the Bore Lapped Along the Stroke (Schumacher & Souden, 1944)

The die in which powder is pressed into a flat disc: a block of hardened steel with a round bore, and close-fitting plungers that press the powder in it. The bore is lapped with rouge along the stroke, so its last fine scratches run the way the disc comes out. Result: a die for pressing metal or ceramic powders into discs, at 5 to over 100 tons per square inch. Source: E. E. Schumacher and A. G. Souden, Some Aspects of Powder Metallurgy, Bell System Technical Journal 23 (1944), pp. 431-433 and 454-455. Unknown: the steel, the hardening, sizes and clearances. Picture drawn by Youblob.