How to find the right Bolts AI guide
Written by an AI model from its trained knowledge.
What the AI looks for in Bolts
- Strength grade
- SAE Grade 5 (three radial head lines) or Grade 8 (six lines); metric 8.8 or 10.9 stamped on the head An unmarked head is low-strength Grade 2 steel and should not go in load-bearing or vibrating joints.
- Material vs. environment
- Zinc-plated for indoor use only; hot-dip galvanized or stainless for outdoors and pressure-treated wood; 316 stainless near salt water Plating corrodes quickly outdoors, and the wrong metal pairing causes galvanic corrosion.
- Thread match
- Match diameter and pitch (UNC coarse, UNF fine, or metric) to the nut or tapped hole Mixed pitches cross-thread and strip, and inch and metric sizes that look alike do not interchange.
- Stainless strength
- 18-8 and 316 stainless are roughly Grade 2 in strength, not Grade 5 or 8 Stainless trades strength for corrosion resistance, so it is the wrong swap for a high-strength steel bolt.
- Nut compatibility
- Hot-dip galvanized bolts need hot-dip galvanized (oversize-tapped) nuts; nut grade should equal or exceed bolt grade Standard nuts bind on thick galvanizing, and a weaker nut strips before the bolt reaches its rated load.
Brands that matter
- Hillman: Broad retail range of common bolt types and grades in small packs.
- Bolt Dropper: Stainless bolt specialist with many sizes sold in small counts.
- Crosby: Lifting-hardware maker known for forged eyebolts.
What to avoid
- Unmarked bolts in structural, automotive or lifting use
- Mixing stainless bolts with galvanized or zinc nuts outdoors
- Reusing stretched or torque-to-yield bolts
Questions
Is a hex bolt the same as a hex cap screw?
Close, but not identical: cap screws have tighter tolerances and a washer face and are meant for tapped holes. Many retail "hex bolts" are actually cap screws.