How to Identify a Hex Bolt’s Grade Every hex bolt has markings on its head that tell you its material grade and mechanical properties. Those radial lines, numbers, and letters aren’t decorative — they’re a specification. Knowing how to read them means you can verify the right bolt is in the right application without pulling … Read more
What is Galvanic Corrosion? When two dissimilar metals are in electrical contact in the presence of an electrolyte (water, salt spray, humidity), the more reactive metal corrodes faster than it would on its own. This is galvanic corrosion — and it’s one of the most common (and preventable) failure modes in mechanical design. The further … Read more
Standard Flat Washer Sizes Flat washers distribute load under a bolt head or nut, protect the surface from damage, and span oversized or slotted holes. The two common types in the US are: Type A (Narrow) — general purpose, standard series Type B (Wide) — larger OD for better load distribution on soft materials Dimensions … Read more
Metric Tap & Clearance Drill Sizes This table covers standard coarse pitch metric threads (the default — if a drawing says “M10” without specifying pitch, it means M10×1.5 coarse). For each thread size, you get the tap drill (for cutting internal threads) and clearance drill (for a bolt to pass through freely). Thread Pitch (mm) … Read more
UNF Tap Drill Sizes UNF (Unified National Fine) threads have more threads per inch than UNC for the same diameter. They’re stronger in thin-walled parts, provide finer adjustment, and resist vibration loosening better — but they’re less forgiving and easier to cross-thread. Thread Size TPI Tap Drill Decimal (in) 75% Thread Clearance Drill #0-80 80 … Read more
UNC Tap Drill Sizes UNC (Unified National Coarse) is the default thread series in the US. If a drawing says “1/2-13” — that’s UNC. Coarse threads are stronger, more forgiving of dirty conditions, and easier to assemble than fine threads. Thread Size TPI Tap Drill Decimal (in) 75% Thread Clearance Drill #1-64 64 #53 0.0595 … Read more
UNF Thread Specifications UNF (Unified National Fine) threads per ASME B1.1. Fine threads have a larger minor diameter than coarse threads of the same nominal size, which means higher tensile strength and better performance in thin-walled parts. Size TPI Major Ø (in) Pitch Ø (in) Minor Ø (in) Tensile Stress Area (in²) #0-80 80 0.0600 … Read more