CNC Turned Aluminum 6061-T6 Bicycle Headset Cup 34mm Press Fit Anodized Black

This bicycle headset cup is machined from Aluminum 6061-T6 (6061-T6) to ±0.015mm in the critical dimensions, then finished by Type II black anodized bearing seat. It is produced on CNC turning centres that are dedicated to small and medium volume precision work, so every dimension on the drawing is generated by the machine rather than by hand fitting. Typical users are engineers who have already been let down by a supplier that quoted a tolerance it could not hold, and who need the part to fit the first time without sorting or rework on the assembly line.

• Press Fit Control: 34mm press diameter held to ±0.015mm so the cup presses into the head tube without cracking the frame
• Square Bearing Seat: 0.015mm squareness at the bearing seat stops bearing cocking and the creaking that follows
• Weight Controlled: 18g per cup keeps the front end light without thinning the wall below a safe margin
• Anodized Seat Surface: Anodize inside the bearing seat reduces wear from repeated bearing replacement
• Chamfered Lead In: Press lead in chamfer prevents shaving material off the head tube during installation

The process route is fixed before metal is cut. Bar stock is verified against the purchase specification and the heat number is logged, then a first article is turned and measured in full. Only after the first article is signed off does the lot run. Critical features on this bicycle headset cup are controlled to ±0.015mm with a process capability target of Cpk 1.33 or better, and the operator checks the feature at a defined frequency with the gauge stated on the control plan. Where the drawing calls for Type II black anodized bearing seat, the finishing step is carried out in house and the result is measured, not assumed. Sample parts go to the CMM for full dimensional verification, and the recorded results ship with the lot as a first article inspection report in PPAP level 3 format when a customer program requires it.

Questions are handled by engineers rather than by sales staff. Our team reviews each drawing for manufacturability, flags features that would drive cost without adding function, and proposes the tolerance band that actually matters for the assembly. That review is free and is returned within 24 hours together with a quotation. When a part fails in the field, we ask for the sample back, section it if needed and report what the failure mechanism was, because a supplier that cannot explain a failure cannot prevent the next one.

• Machines: 50+ CNC units including Swiss type lathes, 3, 4 and 5 axis machining centres and turn-mill centres from Citizen, Star, Doosan and Mazak.
• Quality lab: CMM, 2D vision measurement, roughness tester, hardness tester, salt spray chamber and spectral analyser for material verification.
• Team: 15+ mechanical engineers covering DFM review, process design, fixture design and failure analysis.
• Capacity: 500,000+ precision turned parts per month with stable output and on time delivery tracking.
• Quality system: ISO 9001:2015 certified, SGS audited, material traceability from mill heat to finished part.
• Export experience: parts shipped to 30+ countries across North America, Europe, Japan, Korea and Southeast Asia.

Bicycle frames, e-bike head tubes, custom titanium and steel frame builds, and replacement headset assemblies.

Parts are degreased, dried and packed so that the surface finish specified above arrives intact. Standard packing is VCI paper or individual PE bag, a partitioned foam tray for form features, and an export grade corrugated carton on a pallet, with the lot number and heat number marked on the outside. Parts are warranted against material and workmanship defects for 12 months from delivery. If a part is found outside the drawing, we replace it at our cost and we pay the return freight for the defective lot. Third party inspection by SGS, BV or TUV can be arranged before shipment at your request, and we work under NDA where drawings are confidential.

Q: Will the cup fit both 34mm and 44mm head tubes? A: No, the press diameter is specific. We machine 34mm, 44mm and 55mm standards and will confirm which matches your frame drawing.

Q: How tight should the press fit be? A: A light interference of 0.02 to 0.05mm press is typical for aluminium cups in an aluminium head tube. Too tight and the head tube can crack on installation.

Q: Can you supply the matching bearings and top cap? A: We machine the cup set and can source standard cartridge bearings and matching top caps as a kit.

Q: Do you offer titanium cups for weight? A: Yes, we machine Grade 5 titanium cups for custom builders. Expect roughly 30 percent weight saving at about three times the price.

Q: How do you confirm the Aluminum 6061-T6 material before it is machined? A: Every bar is checked against its mill certificate with an optical emission spectrometer before it goes to a machine. If the chemistry does not match the grade, the bar is rejected and returned. The certificate for your lot is filed under the heat number and can be sent with the shipment or on request.

Q: What happens if a delivered part measures outside the ±0.015mm tolerance? A: Send the measurement and the lot number. We check the recorded values for that lot, replace the parts at our cost and cover the return freight. Because each critical feature is recorded during production, we can trace the deviation to a tool wear step, a fixture shift or a gauge issue and correct the process before the next lot runs.

Send a 2D drawing, a STEP file or a sample and you will have a manufacturability review and a firm quotation within 24 hours. Trial orders from a single piece are accepted, so the tolerance claim can be checked on your own assembly before a production order is placed.