Takeoff
The pass where a print becomes a priced list, every operation, material and quantity the part will actually need, extracted before any number is committed.
When a quote goes wrong, the argument almost always traces back here. The takeoff is where somebody read the print and decided what the part is made of in the manufacturing sense, which features imply which operations, how much material the piece really consumes including the cutoff and facing stock, and which notes on sheet 4 quietly commit you to a cleanliness spec or a source approval. Everything downstream, the routing, the cycle estimates, the supplier requests, inherits whatever the takeoff decided.
The expensive failure is omission. A missed secondary operation, the deburr that the drawing implies without naming, the masking a plating note demands, does not show up as a wrong number on the quote. It shows up as no number at all, and the floor discovers it after award, when the price is already fixed. An operation added after award is paid for entirely out of margin, which is why an hour of careful takeoff is the cheapest hour on the whole quote.
The other argument the takeoff settles is gross against net. Material priced on the finished part’s weight instead of the bar the piece is cut from understates every piece by the kerf and the facing stock, and at program volume that difference is real money. The worked build-up in how to quote a machined part starts from gross length for exactly this reason.
A takeoff you can defend has a source for every line. Feature to operation, note to requirement, dimension to stock size. When a buyer challenges the price 2 weeks later, the estimator who can walk the challenged line back to the sheet that created it wins the conversation, and the one who priced from a glance does not.