How to Order Custom Machined Parts

How to order custom machined parts

Ordering custom parts is easiest when the supplier receives one clear package: the part number, drawing revision, quantity, material grade, finish, critical tolerances and delivery target. The same information lets engineering review the design, select a process and quote the order without guessing. This guide covers the route from the first file to production and dispatch.

For a first request, send a STEP, IGES, DWG, DXF or dimensioned PDF through the request a quote form. A photograph, sketch or existing sample can be included when a drawing is not ready. The more complete the drawing package, the fewer quotation questions are needed.

Step 1: Send the drawing and purchasing requirements

Identify the part number, revision, units, material, surface finish and quantity. Mark the features that control assembly, such as bearing seats, bores, locating faces, hole positions and threads. If the order needs a material certificate, pre-shipment photos, special packing, checking records or a particular delivery term, include that requirement before pricing.

For assemblies or repeat parts, state whether the quote is for a sample, pilot batch or production run. Production orders start from 50 pieces per style and material. Prototype quantities are reviewed against the drawing, so a first sample can be discussed before a larger run.

Step 2: Receive DFM feedback and the quote

We review the geometry, material, quantity, tolerances and finish, then return DFM feedback with a quote within 24 hours. The review may recommend a different process, a practical internal radius, a clearer datum scheme or a tolerance change on a non-functional feature. It can also flag deep holes, thin walls, difficult threads, tight fits and finish requirements that affect the route.

The purpose of DFM is to resolve cost and manufacturability questions before production. It is not a substitute for the buyer’s design approval. If the drawing changes after quotation, send the new revision so the affected features, material usage, process and lead time can be rechecked.

Step 3: Approve the drawing, price and schedule

Before machining starts, confirm the drawing revision, material grade, quantity, finish, required documents and delivery date. General dimensions follow ISO 2768-m unless the drawing states another general tolerance. Precision features can be held to +/-0.01 mm when the process and geometry support the requirement.

Samples typically ship in 5-10 days after drawing approval. Production typically ships in 25-35 days after approval, with the final date depending on material availability, quantity, finishing and any additional checking or packing requirement. The approved quotation should be the reference for the order.

Step 4: Sample approval and production

When a sample is required, use it to check fit, function, finish and the dimensions that matter to the assembly. Record any change against the drawing revision rather than relying on an email description. Once the sample or drawing is approved, the same machining floor can continue into the production batch.

CNC turning is used for round parts such as shafts, bushings and spacers. CNC milling is used for brackets, housings, plates and fixtures. Swiss-type machining supports small, high-volume turned parts, while multi-axis work can reduce setups for features on several faces.

Step 5: Documentation, packing and dispatch

Every order ships with a material certificate (MTR) and pre-shipment photos of the actual finished parts. The packing list and carton markings are prepared before dispatch. If the order needs additional documents, identify them in the RFQ so they can be reviewed before the order is accepted.

For practical file preparation, see the drawing requirements and DFM guide. For questions about materials, tolerances, lead times or documents, review the CNC machining FAQ or send the complete package through the request a quote form.