Fastener Buying Guides

Short, practical guides to picking the right stainless steel fastener: how sizes are written, what fits what, and which type or grade suits the job.

• What does 1/4-20 mean?

  How to read an imperial thread size: the diameter, then the threads per inch.

• How to match nuts and bolts

  A nut fits a bolt only when the diameter and the thread pitch both match. Here is how to check.

• Hex bolt vs. other bolt types

  Hex, carriage, lag and socket head cap screws compared, and which to use for wood, metal and structural work.

• 18-8 stainless steel vs. other grades

  18-8 (304), 316 and 410 stainless compared for outdoor, marine, food-grade and high-strength use.

• Which screw for sheet metal?

  Self-tapping sheet metal screws, self-drilling tek screws and hex washer heads, and when each one fits.

• How to choose the right washer

  Flat, fender and lock washers: what each one does and which to put under a bolt, screw or nut.

• Bolt size chart

  Diameter, threads per inch, head size and wrench size for common hex bolts, lag bolts and cap screws.

• Thread pitch chart

  UNC, UNF and metric thread pitches with tap drill and clearance hole sizes.