This is a long stainless main shaft for a directional drilling tool, with a double helical spiral machined the full length of the body. We turned and bored it, milled the spiral and the hex drive, and cut internal threads on both ends - one Stub Acme and one UNF. After machining we sent it to our heat-treat partner to harden it, which is where the temper colours came from. The spiral is where the time goes - it wraps the whole part and has to stay consistent end to end - and we held the diameters to .003.

Material: Stainless Steel | Operations: Turning, Milling, Threading | Size: around 13" long | Feature: double helical spiral | Threads: internal Stub Acme + UNF | Drive: Hex | Heat treat: hardened (through our heat-treat partner) | Tolerance: diameters to .003"