Key principles.
M3-M50
Metric coarse and fine. ISO 261 standard.
UNC, UNF
UNC coarse, UNF fine. ANSI B1.1 standard.
Use definition
Bolt: tightened with nut. Screw: threads in mating part.
2 standard
Class 2 most common. Class 3 precision.
5.8 mid, 12.9 high
Metric grades. SAE J429 grades 1-8 imperial.
Corrosion
Zinc, nickel, hot-dip galvanized for corrosion resistance.
FAQ
Metric standard worldwide. Imperial in US automotive, industrial. Each has standards.
M3 (3mm), M4 (4mm), M5 (5mm), M6 (6mm), M8 (8mm), M10 (10mm). Default sizes.
Grade 5.8 (low strength), 8.8 (mid), 10.9 (high), 12.9 (highest). Per load.
Thread lockers (Loctite), nylon-locked nuts, helicoils. Per service requirement.
1.5-2× diameter for full thread strength. 1× minimum.
Standard cheap, available. Custom: longer lead time, premium cost. Use standard when possible.
Get an instant quote
Send your CAD — we reply with detailed pricing, lead time, and DFM feedback within 4 working hours.
Talk to an engineer
WhatsApp our team directly. Most messages answered within 12 minutes during work hours.
Explore all services
CNC, 3D printing, injection molding, sheet metal, casting, finishing — one quality system, one partner.
Working on a live project? Send the STEP file and the two or three features you are unsure about — an engineer replies with DFM notes and a price, usually within four working hours.