The seven lines that make a hard steel RFQ quotable

When three shops return three prices that are 4x apart, it is almost never because two of them are greedy. It is because the drawing let them quote three different jobs. Hardened steel amplifies this: one ambiguous line about heat treat can move the cost more than the part geometry does.

Here is the set of answers that makes quotes comparable.

1. Grade, and whether an equivalent is acceptable

“Tool steel” is not a grade. “D2” is. “D2, or SKD11 / 1.2379 equivalent accepted” is better, because it lets the shop quote material that is already in the country instead of importing a bar.

2. Hardness, and when it is reached

State both the target and the sequence:

• Supplied annealed, we harden after — the shop quotes soft machining only.
• Machine soft, shop hardens to 58-60 HRC, shop finishes after — the shop carries distortion risk.
• Supplied at 58-60 HRC, machine as is — hard milling, CBN, different shop list entirely.

These are three different prices for the same drawing.

3. Which tolerances are real

Mark the two or three dimensions that actually matter and let the rest sit at a general tolerance class. A blanket ±0.01 mm on a 40-dimension part buys inspection time, not function.

4. Surface finish on functional faces only

Ra 0.4 on a sealing face is reasonable. Ra 0.4 on all faces of a die block is a polishing operation nobody needed.

5. Quantity — and the quantity after this one

“4 pieces” and “4 pieces now, then roughly 40 a year” are priced differently, because the second justifies fixturing. Say the real forecast even if it is uncertain.

6. Post-processing, named

Nitriding, PVD coating, black oxide, wire EDM for the sharp internal corners, grinding for the final 0.02 mm. If the shop has to guess, they either quote without it or quote defensively.

7. Inspection and documents

A dimensional report, a material certificate, a hardness test — each is cheap when planned and expensive when requested after the parts are cut. First-article inspection on a 4-piece order usually is not worth it; on a die that feeds a production line, it is.

The file itself

Send a STEP file and a dimensioned PDF. The STEP removes geometry ambiguity; the PDF carries tolerance, finish, heat treat and notes. A STEP alone means the shop is guessing at your tolerances; a PDF alone means they are rebuilding your model.

Answer those seven and the spread between quotes usually collapses to something that reflects capability rather than interpretation.