Shoulder Screws Precision Ground Shoulder Bolts For Pivot Spacer Locating And Sliding Assembly
Shoulder Screws consist of three core sections: drive head, precision‑ground unthreaded shoulder and threaded end. Different from ordinary full‑thread machine screws, the smooth shoulder bears locating, pivoting, sliding and shear load, while the threaded segment only provides clamping preload. This separation of functions eliminates wobble and inconsistent spacing on rotating or sliding assemblies.
This series of Shoulder Screws targets B‑end OEM manufacturers, fixture designers and precision machinery contractors. Widely deployed where accurate alignment, controlled rotation or fixed spacer height is required.
Core Features & Competitive Advantages
- Separated Function Design: Locating Shoulder plus Clamping Thread Our Shoulder Screws adopt independent shoulder‑thread structure. The precision‑machined smooth shoulder acts as pivot axle or spacer datum; threads only undertake clamping force. Tightening torque will not change the spacing height of mating components, avoiding binding and wear on moving parts.
- High‑Precision Ground Shoulder With Strict Tolerance Control The shoulder surface is precision ground to achieve low‑friction smooth finish. We can deliver h6 / g6 / h7 tolerance grades for shoulder diameter, concentricity and surface roughness. Stable dimensional accuracy guarantees repeatable positioning performance for bearing, bushing and linkage assemblies.
- Multiple Head Types, Material And Heat‑Treatment Options Available drive styles: hex socket, Phillips pan head, torx, slotted. Material covers SUS304 / SUS316 stainless steel, 8.8 /10.9 /12.9 alloy steel. Heat‑hardened alloy steel suits heavy‑load shear scenarios; stainless steel variants fit humid and corrosive working environments.
- Stock Sizes Plus Full‑Dimension Customization Metric sizes M3‑M20 and partial imperial sizes kept in stock. Custom shoulder diameter, shoulder length, thread specification, head geometry and special tolerance can be manufactured according to customer drawings or physical samples. Nylon patch anti‑loose coating can be applied onto threaded portion for vibration‑prone assemblies.
- Wide Compatibility For Complex Mechanical Structures Designed for pivot joints, jig & fixture, cam followers, robotic linkages and spacer stacking. Eliminates extra dowel pin or separate spacer parts, simplifies bill‑of‑materials and shortens assembly cycle.
Technical Parameters & Specifications
| Parameter Item | Standard Data | Custom Option |
|---|---|---|
| Product Name | Shoulder Screws | Custom logo marking on screw head |
| Drive / Head Type | Hex socket, Phillips pan head, Torx, Slotted | Special non‑standard head & drive profile |
| Shoulder Tolerance | h6, g6, h7 | Custom tight tolerance upon drawing |
| Thread Standard | Metric ISO DIN / Partial Imperial | Custom fine thread specification |
| Size Range | Metric M3‑M20 | Custom shoulder dia, shoulder length, thread size |
| Material | SUS304, SUS316, 8.8 /10.9 /12.9 Alloy Steel | Special alloy material on request |
| Surface Finish | Zinc Plating, Black Oxide, Nickel Plating, Passivation | Nylon‑patch anti‑loose coating, special coating |
| Working Temperature | -40℃ ~ 120℃ | Custom coating for special temperature |
| Minimum Order Quantity | 1000 PCS | Small trial‑batch orders acceptable |
Application Scenarios & Industry Cases
Shoulder Screws are widely deployed for precision mechanical assemblies, not intended for medical‑device usage:
- Automation & Robotics: Robotic joint linkages, rotating hinge components, conveyor pivot assemblies
- Jig And Fixture Systems: Tooling fixtures, die sets, positioning pin assemblies for machining stations
- Precision Instrument Equipment: Cam followers, sliding modules, bearing‑mounted rotating sub‑assemblies
- Automotive Components: Small pivot joints, door hinge sub‑parts, interior mechanical linkages
- General Industrial Machinery: Spacer stacking assemblies, pulley and lever rotating mechanisms
Real‑World Project Case: One automation equipment OEM replaced combination of machine screw plus separate spacer‑dowel assembly with our Shoulder Screws. BOM item count reduced, on‑site assembly time dropped by 31 %, and positioning deviation failure rate decreased significantly. Both parties maintain stable multi‑year large‑volume order cooperation.
Customer Pain Points & Targeted Solutions
Common Fastener Pain Points Faced By Industrial Manufacturers
‑ Using ordinary machine screws for pivot assemblies: threads directly contact bore, resulting in heavy wear, jamming and rotational wobble
‑ Separate dowel pins plus spacers plus screws lead to many BOM parts, slow assembly and accumulated tolerance error
‑ Uncontrolled shoulder tolerance causes poor fit for bearing / bushing mating
‑ Limited standard sizes cannot match non‑standard shoulder length and diameter requirements for custom mechanism designs
Solutions Provided By Shoulder Screws
‑ Separated shoulder‑thread functional design: smooth ground shoulder undertakes rotation / sliding movement, threads only for clamping, greatly reduce friction wear and rotational play
‑ All‑in‑one integrated fastener replaces screw + spacer + locating pin combination, simplify parts list and lower cumulative tolerance error
‑ Selectable shoulder tolerance grades (h6/g6/h7) to match clearance or interference fit requirements for bearing and bushing parts
‑ Full‑range drawing‑driven custom service for shoulder diameter, length, thread and head shape to satisfy unique mechanical‑structure demands
Factory Production Strength & Supply Support
We are a professional fastener manufacturer with mature complete production system. We own independent CNC turning‑grinding workshop, heat‑treatment workshop and full surface‑treatment production lines. The full production workflow of Shoulder Screws is completed in‑house inside our plant.
Core Supply Advantages:
- 7‑day quick sample turnaround for custom specifications
- Large‑volume stock for standard metric & partial imperial sizes; mass goods shipment within 3 working days
- Strict pre‑delivery inspection including shoulder dimension, concentricity, surface roughness and thread test; defective rate controlled below 0.5 %
- Comprehensive OEM & ODM support: drawing customization, customized‑package service
- Complete test‑report supply: tensile‑strength test, hardness test, dimensional inspection documents
Purchase Guide & After‑Sales Support
Payment Term: T/T, L/C at sight
Delivery Port: Major China seaports
Certification: ISO9001, SGS material certification, relevant industrial fastener‑standard certification
Full‑Set After‑Sales Support
- Professional engineering team provides online technical consultation to help you select proper model of Shoulder Screws
- Free technical‑spec sheet and installation‑reference documents available upon request
- Quality‑caused defective products qualify for free replacement & compensation within warranty scope
- Exclusive preferential‑price policy for long‑term bulk‑order cooperative customers
