Machining method: cylindrical lapping.
Ra: 1, 2, 4, 8_in. Rz: 18, 22, 25, 49_in. Quantity 4pcs; superfinishing. Ra: 1, 2, 4, 8_in. Rz: 14, 28, 40, 56_in. Quantity 4pcs.
For checking, identifying and specifying the roughness by symbol.
Rust-proof, made of pure Nickel.

3M 66039, Push-Ins Probed Test Plugs 393-2015-50, with Grip Rings, 50 EA/Case, 7000148552
3M 33439, Cubitron II File Belt, 33439, 60+, 10 mm x 330 mm (3/8 in x 13 in), 7100033194, 10 belts per carton, 5 cartons per case
3M 12953, Scotch-Brite Roloc Surface Conditioning Disc, SC-DR, A/O Medium, TR, 4 in, 7100007035, 100 per case 