The Brief
Triple clamps hold the front forks to the steering stem of a motorcycle — they're a safety- and handling-critical structural part. A customer needed a custom set machined from billet, either to suit non-standard fork tubes, to change the offset, or simply because the original was no longer available. Cast or forged clamps weren't an option for a one-off; this had to be cut from solid.
The real challenge: three bores have to be right — the two fork-tube clamp bores and the central steering-stem bore — at the correct spacing and parallelism. Everything else is shape. Get the bores and spacing right and it fits; get them wrong and it's scrap.
How It Was Made
1 — Lock down the fitment dimensions
Before any metal moved, the dimensions that decide fit were established and confirmed: fork-tube diameter and clamp bore, steering-stem diameter, and the centre-to-centre spacing between them. Where the customer had the original clamp or fork tubes, those were measured directly as the reference — the same reverse-engineering approach used across our reverse engineering work.
2 — Mill from solid 6061
The clamp was milled from a solid block of aircraft-grade aluminium. The sculpted outer form is cut on multiple faces; the precision clamp bores and stem bore are bored and reamed to a controlled diameter so the fork tubes slide in with the correct pinch fit once the clamp slots close.
3 — Finish & anodize
After deburring and a fine surface finish, the part is anodized — both for the hard, corrosion-resistant surface a structural part needs and for the look. Aluminium grade and finish are matched to the customer's requirement; see aluminium machining for the alloy options.
The Workflow
Confirm fitment
Fork-tube bore, stem bore and centre spacing measured/confirmed before machining.
Mill from billet
Sculpted body cut on multiple faces from solid 6061; bores roughed.
Bore & ream to fit
Clamp and stem bores finished to a controlled diameter and parallelism.
Anodize & inspect
Hard anodized finish applied; bores and spacing inspected before shipping.
Outcome
A finished billet triple clamp that drops onto the intended forks and stem with the right fit — produced as a one-off without any tooling. This is typical of the motorsport and automotive CNC work we do: parts where the appearance matters but the fit and structural integrity matter more, machined from solid so a single piece is economical.
Have a custom or discontinued bike part? Send your design, the original part, or photos with key dimensions. We machine it from billet — one piece or a small run. Email [email protected] or message us on WhatsApp.