Guides / For Shops

What Bike Parts Machinists Want From a Metal Supplier

September 25, 2026

Bicycle component machinists are a small, particular kind of metal customer. The orders are modest, the specifications are narrow and the retention is high once you are in. Here is what they actually need.

The alloys, and nothing much else

6061-T6 is the workhorse. Stems, brackets, seat collars, spacers, cages. It cuts fast and it anodizes evenly, which matters downstream.

7075-T6 is the high strength option. Cranks, chainrings, direct mount rings, thin section parts where the geometry cannot grow.

Small volumes of titanium Grade 5 for axles and bolts, 303 or 17-4 PH stainless for pins and shafts, occasionally AZ31 magnesium for weight critical work and Delrin for pulleys and guides.

A supplier who stocks 6061 and 7075 in a decent spread of bar and plate sizes covers most of the segment.

Stock size is a cost decision, not a convenience

Machining is subtractive and bike parts are heavily pocketed. A finished stem might weigh 130 grams and start as a 400 gram block. The customer pays for the block.

This has a practical consequence you can profit from: a machinist choosing between two stock sizes is making a material cost decision worth tens of percent. A supplier who carries the intermediate sizes, and who will say “we have 55 mm as well as 60 mm, that saves you a size”, is solving a real problem rather than filling an order.

Carrying a sensible ladder of sizes matters more in this segment than carrying exotic alloys.

Mill certificates are not optional paperwork

Ask a bike parts machinist about certificates and you will get a firmer answer than from most job shops. Two reasons.

Testing. Structural components get fatigue tested to ISO 4210 or EN 15194. A test is only defensible if the material is traceable to a lot, and the brand keeps the certificate in a file alongside the test report and the inspection record. A batch shipped without traceability cannot be retrofitted with it.

Consistency. Anodize color shifts between mill lots. A brand matching a stem, a collar and a set of spacers in one black is exposed to material variation it cannot see until the parts come out of the bath.

So: supply certificates as routine rather than on request, keep lot traceability, and tell the customer when a lot changes. That last one costs you nothing and it is the kind of thing that keeps a customer for five years.

The downstream process you are affecting

Most metal suppliers never think about what happens after machining. Here it decides whether the part is accepted.

Nearly every machined bike part is anodized, and anodize is a color-critical consumer finish. Surface condition, alloy and mill lot all move the result. A brand that gets two different blacks out of one product range will trace it back, and sometimes it traces back to material.

You do not need to solve this. You need to know it exists, because a supplier who says “that lot is from a different mill, expect a slight shift in anodize” is giving information nobody else in the chain is giving.

What the orders look like

	Typical
Order size	A few bars to a few hundred kilos
Frequency	Seasonal, tied to a model year, often twice yearly
Alloys	6061-T6 and 7075-T6, over 80 percent of it
Forms	Round bar and plate, occasionally extruded profile
Paperwork	Mill certificate as standard, lot traceability
Price sensitivity	Moderate. Reliability and traceability beat small savings
Switching	Rare, once color and test results are settled on a source

Low volume, high retention. It suits a stockist who will take a small order politely and get the paperwork right. It suits a mill selling by the tonne poorly.

Three things to put in a first reply

1. What you stock, in sizes. Not a capability list, an actual size ladder in 6061 and 7075.
2. Certificates as standard, with lot traceability. State it, do not wait to be asked.
3. Minimum order and cut charges. Small orders are the norm here, so a clear small order policy is a selling point, not an apology.

If you supply aluminum or specialty metal to machine shops, register as a vendor. Free to list, and the shops making bike components come looking for exactly this.

Frequently asked questions

Keep reading

• What Bike Parts Work Asks of an Anodizing Shop
• Testing Bike Components: What Brands Actually Need