Valve Body Casting + CNC RFQ Package: Ports, Threads, Datums, and Inspection

# Valve Body Casting + CNC RFQ Package: Ports, Threads, Datums, and Inspection

Valve bodies are machining-driven parts. A “valve body casting” quote that ignores thread callouts, bore relationships, datum strategy, and inspection outputs is usually not a real quote — it is a placeholder.

This guide shows what to include in an RFQ package so suppliers can quote valve body castings with machining reality included.

If you are sourcing valve bodies, these pages are the fastest RFQ paths:

• •Valve body manufacturer landing
• •Valve body RFQ path
• •Request quote + drawing upload

1) Drawings and models: what valve body suppliers actually need

Send:

• •2D PDF drawing with revision and tolerances
• •3D STEP model (preferred)

For valve bodies, add clarity on:

• •all threaded ports (thread type, class, depth, chamfer notes)
• •any intersecting drilled passages (and whether cross-holes must be deburred or plugged)
• •bore relationships (coaxiality, true position, and which bores are “function critical”)
• •datum structure (which faces locate the part in machining and inspection)
• •sealing faces and surface finish targets

2) Define the machining scope as a list, not a sentence

Instead of “machining required”, list:

• •machined faces (mounting pads, cover faces, sealing lands)
• •drilled holes and tapping operations (including reaming if required)
• •bores to machine (diameter tolerance, roundness if relevant)
• •thread gauge requirement (if your QC requires Go/No-Go, state it)

If you want a structured template for casting + machining, see: A356 casting plus CNC machining RFQ package.

3) Material/process: be explicit or ask for recommendation

State one of:

• •alloy and temper (example: A356 with T6), or
• •“recommend alloy and heat treatment based on pressure, load, and corrosion needs”

Also state process preference if you already know it:

• •gravity casting
• •low-pressure casting
• •die casting

If you are unsure, ask for supplier recommendation with reasoning.

4) Inspection and approval outputs: prevent late-stage re-quotes

For valve bodies, inspection scope can change cost materially.

In the RFQ, specify whether you need:

• •CMM report (and how many characteristics are critical)
• •material certificate and traceability level
• •surface finish report (if sealing faces have Ra targets)
• •pressure/leak test (if the valve body is pressure boundary)
• •PPAP or FAI package (only if your program requires it)

Reference for quality systems and inspection methods: Quality control.

5) Volume + release pattern: what changes tooling and unit price

Include:

• •annual volume and forecast stability
• •pilot build quantity and sample approval quantity
• •any expected engineering changes (ECR/ECO timing)
• •delivery terms (incoterm + destination)

6) “Unknowns” list: make decisions visible instead of hidden

If you have open decisions, list them directly so suppliers quote comparable assumptions:

• •casting process: fixed vs supplier recommend
• •core strategy: fixed vs supplier propose
• •machining sequence ownership: supplier complete vs buyer-side machining
• •pressure/leak test: required vs not required vs supplier propose

Copy-paste RFQ starter (valve body)

> Part: aluminum valve body casting + CNC machining RFQ

> Files: 2D PDF (rev __), 3D STEP

> Annual volume: __ / year; prototype: __; pilot: __

> Alloy/temper: __ (or “recommend”)

> Process: gravity / low-pressure / die casting / recommend

> Machining: datums __; critical bores __; ports/threads __; sealing faces Ra __

> Inspection: CMM __; material cert __; thread gauge __; PPAP/FAI __

> Timing: target sample date __; SOP __

> Questions: confirm tooling approach + sample correction loop; confirm inspection outputs and records

FAQ

Why do valve body quotes change after the first discussion?

Because the machining truth appears late: datums, thread callouts, bore relationships, and inspection outputs. Put those items into the RFQ package upfront to keep quotes stable.

Do I need to specify threads and ports in the RFQ if they are on the drawing?

You do not need to rewrite the drawing, but you should highlight which ports, bores, and sealing interfaces are function critical and whether special gauges or inspection records are required.

What is the best next step if I am comparing two suppliers?

Make sure both suppliers quote the same assumptions: process route, machining scope, inspection outputs, volume/MOQ, and approval flow. Then submit through the formal RFQ page so the comparison uses one consistent package.