Custom CNC Ground
Precision Pin Shafts

A precision pin shaft (locating pin, dowel pin, or pivot pin) is a cylindrical shaft machined to very tight diameter and cylindricity tolerances for use in precision location, hinge pivots, and rolling element applications. Unlike a standard shaft, a precision pin's primary function is to locate two mating parts accurately — the tolerance of fit (pin-to-hole clearance or interference) directly controls the positional accuracy of the assembly.

Precision pin diameter tolerances: IT4 — gauge quality, roller pins, very high-precision dowel pins. IT5 (g5, h5) — standard precision dowel and locating pins. IT6 (h6) — lower-cost locating pins and hinge pivots. The pin tolerance combined with the mating bore tolerance determines the fit (clearance, transition, or interference). HXC grinds pins to any tolerance class; specify the nominal diameter and tolerance designation (e.g., Ø8h5) on your drawing.

Cylindricity measures how closely the pin approximates a perfect cylinder — accounting for roundness at every cross-section AND straightness of the axis. For a locating pin, poor cylindricity means the pin contacts the mating bore on only part of its length, causing tilting and reduced location accuracy. HXC achieves cylindricity ≤ 0.001 mm on precision pins by grinding between centres with multiple dressing passes.

42CrMo4 / D2 tool steel (HRC 58–62): maximum wear resistance for high-cycle jig and fixture pins. GCr15 (52100) bearing steel (HRC 60–64): for roller pins and very high-load pivot pins. SUS303/316L stainless: food, medical, and marine pivot pins. Ti Grade 5: aerospace and biocompatible implant pivot pins. Brass C36000: low-load, corrosion-resistant hinge pins.

Prototype (1–5 pcs, turned + ground): 4–7 days. Small batch (10–50 pcs): 7–12 days. Production (100–1,000 pcs): 10–16 days. Stainless or titanium: add 2–4 days. Rush production available.

42CrMo4 (induction hardened) for industrial and automotive. 20CrMnTi (carburized) for maximum surface fatigue. SUS303/316L stainless for food, pharma, marine. Al 6061/7075 hard-anodized for lightweight. Ti Grade 5 for aerospace/medical. PEEK/POM for sterilizable or self-lubricating applications.

Standard ground OD: Ra 0.4 µm. Precision bearing seats: Ra 0.2 µm. Mirror finish for seals: Ra 0.1 µm. All measured by contact profilometer and reported on the inspection certificate.

Yes — keyways, splines, threads, cross-holes, flats, and tapers are all machined in the same 5-axis turning-milling setup, ensuring concentricity between all features within 0.003 mm TIR.