This is an alloy steel mandrel adapter - really a thread crossover, with a bigger Stub Acme pin thread on one end and a smaller Stub Acme box thread bored and cut into the other. It also carries a bolt circle of holes and a set of spanner grooves around the body. What made this one interesting was the quantity: we ran a batch of about 1,000, so it was as much about a repeatable, dialed-in setup as the first good part. Turned, single-point threaded both ends, and drilled on a fixture to keep every piece the same.

Material: Alloy Steel (chromoly) | Operations: Turning, Threading, Drilling | Size: around 1-3/8 in long, ~1.9 in OD | Threads: Stub Acme pin + Stub Acme box | Feature: bolt-circle of holes, spanner grooves | Quantity: production run (~1,000 pcs)