Non-Standard Stepped Edge Milling Bolt

Product introduction

This is a customized non-standard screw designed for precise positioning and anti-rotation requirements. Its core is the precise step structure and milling process. The steps can be used for shoulder positioning or height control. The milling design can effectively prevent the bolt from rotating under vibration conditions.

As a typical non-standard screw, we can fully customize the step diameter, length and milling angle, and can accurately process various special-shaped screws to meet the demanding assembly requirements of molds, automation equipment and precision tooling. The products are made of alloy steel, stainless steel and other materials, support customization based on drawings and samples, and implement a strict ISO quality control system to ensure that every non-standard part has excellent mechanical properties and assembly accuracy.

 

Product design and features

Precision step structure: The bolt shaft is designed with tolerance steps of different diameters. This step can not only be used to accurately control the assembly height (shoulder positioning), but can also be used as a retaining edge for bearings or gears, achieving multiple functions. The diameter, length and verticality of the steps can be customized according to the working conditions.

Anti-rotation milling design: mill a flat surface (single side, double side or square) on the head or step pole. This special-shaped screw feature allows it to match the milled flat hole on the workpiece or the notch of the fixture after installation, effectively preventing the bolt from rotating in a vibration environment and facilitating one-sided locking.

Head geometry customization: In addition to standard external hexagons, we support internal hexagons, slotted heads, and even special-shaped heads to ensure that the tool can reach any narrow installation space.

Mechanical optimization: For the stress points of non-standard screws, we optimize the R-angle transition at the root of the step to significantly improve the fatigue strength and avoid fracture caused by stress concentration.

 

Materials and application fields

Alloy steel (grade 10.9/12.9): suitable for high-strength requirements, such as engineering machinery, hydraulic equipment, and heavy-duty clamps. It is blackened or galvanized to be rust-proof and wear-resistant.

Stainless steel (304/316): suitable for highly corrosive environments such as food machinery, medical equipment, and marine engineering, with excellent weather resistance and hygiene levels.

Brass/Aluminum Bronze: Suitable for power electronics and marine fields that require non-magnetic, explosion-proof or high conductivity.

 

Typical applications:

Mold manufacturing: used as limiting column and lock module, using step height to control the mold opening stroke.

Automation equipment: Used as a positioning pin for a conveyor line or a connector for a robot arm. The milled edge design ensures that the installation angle never deviates.

Precision tooling: used as special-shaped screws in inspection tools to quickly position and compress workpieces.

 

Quality control and certification system

Full-size first inspection: Before each batch of customized non-standard screws is put into production, a three-dimensional coordinate measuring instrument is used to conduct full-size inspection on step height, coaxiality, and milling symmetry to ensure zero deviation between the drawing data and the actual processing.

Hardness and performance testing: For high-strength alloy steel materials, hardness testing and guaranteed load testing are conducted batch by batch to ensure that non-standard screws do not undergo plastic deformation under the ultimate torque.

Flaw detection: For bolts in critical safety parts, ultrasonic or magnetic particle inspection can be optionally used to check for internal micro-cracks.

Certification system: The factory has passed IATF 16949 or ISO 9001 certification. The products comply with RoHS standards and can provide comprehensive material certification and performance test reports.

 

Customized services

Customized drawings (OEM): The customer provides the final drawing, and we review the process and recommend the most economical tolerance level and material heat treatment plan.

Reverse Development (ODM): Only sample or assembly needs? Based on the installation space, force size and functional requirements you provide, we reversely design the step height, milling edge position and thread specifications to create unique and special-shaped screws.

Personalization parameters:

Step tolerance: can be controlled at h6/h7 precision fit level.

Milling form: single flat, double flat, square, hexagonal or customer specified angle.

Surface treatment: environmentally friendly colored zinc, Jiumeite, Teflon, Dacromet, etc.

 

FAQ

Q: What is the difference between step milling bolts and ordinary step screws?

A: Ordinary step screws usually only have the function of shoulder positioning. Our special-shaped screw has an anti-rotation function by adding a "milled edge" design. This is an extremely critical upgrade for those situations where the nut cannot be locked from the back, or is easily loosened by vibration (such as guide rail installation, fixture positioning).

 

Q: The bolt step I want is very long, and a flat surface needs to be milled on it. Will the strength of this non-standard screw be affected?

A: This is where the difficulty lies in designing non-standard screws. We will conduct simulation calculations during design to ensure that the cross-sectional area loss of the bolt is within a safe range and does not affect its tensile and shear strength by optimizing the thread ending position, increasing the step transition fillet, and strictly controlling the milling depth (usually no more than 1/4 of the diameter).

 

Q: How to purchase such customized non-standard screws? How long does it take for delivery?

A: You only need to provide drawings or specific usage requirements (such as force size, installation plate thickness, anti-rotation requirements). For conventional customized non-standard screws, after the mold fee is shared, the sample delivery time is usually 7-10 days, and mass production is 15-20 days (depending on the complexity).

 

Q: Are there strict requirements for the direction of milling?

A: Yes. For special-shaped screws with directional requirements, we can clearly mark the angular tolerance of the milled edge relative to the starting point or head of the thread in the drawing. We will use the indexing device on the machining center to accurately ensure the phase angle you need.

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