The RFQ checklist: what shops need to quote your work

Why this matters

Every machine shop owner has the same complaint: incomplete RFQs. A CAD file with no drawing, no material callout, no tolerance spec, and no quantity leads to one of three outcomes: the shop ignores it, the shop guesses and over-quotes to cover risk, or the shop under-quotes and loses money.

A complete RFQ signals that you're serious, you understand manufacturing, and you'll be easy to work with. Shops prioritize these buyers because they're more likely to result in profitable, repeatable work.

The essentials

3D model (STEP preferred)

STEP files are the universal standard. Every shop can open them, every CAM system can process them. Avoid proprietary formats (SolidWorks native, Inventor native) unless you've confirmed the shop uses that software. STL files are fine for 3D printing but useless for CNC — they contain no dimensional data.

2D drawing with GD&T

The 3D model defines geometry. The 2D drawing defines intent — which dimensions are critical, what tolerances are required, where surface finish matters, and what reference datums to use. A part without a drawing is a part without specifications. The shop will either assume commercial tolerances or call you to ask — adding lead time to the quoting process.

Material specification

Not just "steel" or "aluminum." Specify the grade: 4140 pre-hard, D2 tool steel, 6061-T6, 7075-T651, 303 stainless, 316L. The material grade determines machinability, tooling selection, cycle time, and cost. It also determines which shops can handle it — hardened tool steel is a fundamentally different job than aluminum.

Quantity and release schedule

1 piece, 50 pieces, and 5,000 pieces are three completely different jobs with three different setups, tooling strategies, and per-part costs. If this is a recurring order, specify the release schedule (monthly, quarterly) so the shop can plan capacity and potentially offer better pricing for committed volume.

Tolerance callouts

If your tightest tolerance is ±0.0005", that's critical information that determines machine selection and cycle time. If everything is ±0.005", the shop has much more flexibility. Call out which features are critical and which are cosmetic — it saves the shop from holding unnecessarily tight tolerances on non-functional dimensions.

Surface finish requirements

32 Ra, 16 Ra, 8 Ra — each requires different tooling, speeds, and potentially secondary operations. If certain surfaces are cosmetic (visible to end users), call that out explicitly. If as-machined is acceptable, say so — it saves time and money.

Secondary operations

Heat treatment, plating, anodizing, grinding, lapping — these affect lead time, cost, and which shops can handle the full scope. A shop that can machine and heat treat in-house will give you a better price and faster turnaround than one that needs to ship your parts to three different vendors.

The details that separate good RFQs from great ones

Delivery timeline: Rush, standard (2-3 weeks), or flexible. If you have a hard deadline, say so upfront — the shop needs to know if this fits their schedule before they invest time quoting.

Inspection requirements: First article inspection (FAI), CMM reports, certificates of conformance, material certs (MTR). These add cost and time — don't require them if you don't need them, but specify them if you do.

Application context: A sentence about what the part does helps the shop understand what matters. "This is a locating pin that indexes off the OD" tells the machinist which features are functional. It doesn't need to be a paragraph — just enough for the shop to make smart decisions.