Shoulder Screws

Shoulder Screw Selection — Quick Reference (ISO 7379)

Shoulder screws (shoulder bolts) = PRECISION-GROUND CYLINDRICAL shoulder + threaded end. ROTATION + PIVOT applications — perfectly round shoulder acts as bearing surface. Machinery + jig + fixture + linkage. ISO 7379 standard.

Critical: Shoulder DIA + LENGTH are PRECISION-GROUND tolerances — order to fit the rotating bushing / bearing. NOT a substitute for a dowel + flat-head cap screw — different mechanical principle. See shoulder bolt guide. Brands: Bremick, Hobson. Companion: socket head cap screws, fasteners.

Shoulder Screws (Shoulder Bolts) for Australian Engineering and Toolmaking

Shoulder screws — also called shoulder bolts or stripper bolts — have a precision-ground shoulder section between the head and the threaded section. The shoulder provides a bearing surface for rotating components, a precise length for spacer applications, or a dimensional locator for assembly work. For Australian engineering, toolmaking, and machinery applications, shoulder screws are the right choice for any joint requiring precision positioning, rotation, or shoulder-to-shoulder bearing. AIMS Industrial supplies shoulder screws across the metric and imperial sizes Australian trade and industrial customers use.

How shoulder screws are constructed

A shoulder screw has three sections from the head down: a head (typically socket head / Allen drive), a precision-ground shoulder section (longer than the threaded section), and a threaded section (shorter than the shoulder, with a smaller diameter). The shoulder is ground to a tight tolerance — typically h6 — providing the precision bearing surface. The threaded section is smaller in diameter than the shoulder, allowing the shoulder to bottom against the mating surface while the thread engages a tapped hole.

Where shoulder screws earn their place

• Pivot joints — providing a bearing surface for components that rotate or pivot
• Bearing-mounted pivots — precision shoulder for bearings to ride on
• Press tool stripper plates — original "stripper bolt" application; precise stripper-plate-to-die positioning
• Spacers and stand-offs — precise-length spacing in mechanical assemblies
• Linkage and lever pivots — pivoting joints in mechanical linkages
• Custom machinery and toolmaking — anywhere a precision bearing-on-shaft is needed without using a separate shaft and circlip

Sizing — shoulder and thread together

Shoulder screw sizing is given as shoulder diameter × shoulder length × thread size. For example, "10mm × 25mm × M8" indicates a 10mm-diameter precision shoulder, 25mm long, with M8 thread for fastening. The shoulder diameter typically corresponds to a standard bearing bore, allowing direct bearing mounting on the shoulder. Common metric sizes range from 5mm through 25mm shoulder diameter.

Materials and grades

• High-tensile steel (10.9 or 12.9) — the standard material for shoulder screws in mechanical applications
• Stainless steel (A2 / 304 or A4 / 316) — for corrosive and food-contact environments
• Black oxide finish — typical finish for high-tensile steel shoulder screws

Drive types

Most shoulder screws use socket head (Allen / hex socket) drive — the head dimensions match the shoulder diameter for compact assembly. Slotted, button head, and Torx variations are available for specific applications.

Specifying for bearing applications

For shoulder screws used as bearing pivots, the shoulder diameter must match the bearing bore exactly, and the shoulder length must match the bearing width plus appropriate clearance for axial location. Match the bearing series (typically standard ball bearings or needle bearings) to the shoulder; verify dimensional tolerance fits before committing the design.

Brands stocked at AIMS

Hobson and Bremick cover the shoulder screw range across the standard metric and imperial sizes. For specialty sizes or non-standard configurations, sourcing through our distribution channels covers most options.

Installation

Shoulder screws are typically installed using socket head drive (Allen key or socket bit). Tighten to the manufacturer-specified torque against the shoulder bottom — the shoulder bottoming against the mating surface is what provides the precise positioning. Don't over-tighten — that can damage the shoulder-to-thread transition or distort the mating surface.

Companion ranges at AIMS

Shoulder screws sit alongside our broader fastener range — see socket countersunk screws, spacers, needle roller bearings, and shaft collars for the related products.

Need help with shoulder screw selection for a pivot, bearing mount, or precision assembly? contact our team — we'll match by shoulder diameter, length, and thread size.