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Component Guide

Locating Pins

Locating pins fix a workpiece in a repeatable position on a jig or fixture. The round-plus-diamond pair is the standard method of constraining a part without over-constraint.

What are locating pins?

A locating pin is a hardened, precision-ground pin that engages a hole in the workpiece to define its position. Fixtures typically use one round pin (primary location) and one diamond (relieved) pin to absorb hole-pitch tolerance — giving exact, repeatable placement every load.

Typical materials

Typically hardened SUJ2 bearing steel or SKD11, ground to tight diameter tolerance; some types supplied with press-fit or threaded mounting.

Types of locating pins

Round locating pins

Full-diameter engagement — the primary datum pin.

Diamond (relieved) pins

Contact on two flats only, absorbing centre-distance tolerance without play.

Shouldered locating pins

Flange sets seating height and takes insertion load.

Tapered / bullet-nose pins

Lead-in taper for fast, guided part loading.

How to select locating pins

  • Workpiece hole diameter and the fit class required.
  • Round + diamond pairing for two-hole location.
  • Mounting style — press-fit, shoulder seated, or threaded.
  • Height of the working land and lead-in form for loading.

Not sure? Send what you have — a part number, drawing or photo — and our engineering team will confirm the selection.

Frequently asked questions

Why use one round and one diamond locating pin?
Two round pins over-constrain the part: any hole-pitch variation makes loading tight or impossible. The diamond pin locates in one direction only, absorbing pitch tolerance while still preventing rotation.
Can JIDOKA supply locating pins to a specific fit?
Send the hole size, fit or the drawing through Request a Quote and our engineering team will confirm the matching pin specification.

Related components

Need locating pins?

Tell us the specification, quantity and application — or just send the drawing.