Mike M. 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 Machinability? Machinability is how easy (or difficult) a metal is to cut with standard machining operations — turning, milling, drilling. It’s expressed as a percentage relative to AISI 1212 steel, which is the baseline at 100%. Higher percentage = easier to machine = lower cost. If you’re selecting a material and you have … 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
Why You Need This Table Working with international suppliers or drawings from outside the US? The same steel has different names in different countries. This table maps the most common structural and engineering steels across seven national standards. Carbon & Alloy Steel Cross-Reference EN (Europe) SAE/AISI (US) UNS DIN (Germany) BS (UK) UNI (Italy) JIS … Read more
Decoding Steel Numbers Every time you see a steel callout like “4140” or “1018,” there’s a system behind those digits. The AISI/SAE numbering system tells you the steel’s composition at a glance — once you know how to read it. How the System Works Steel designations are typically 4 digits: XXYY First digit (X) — … Read more
What is Sheet Metal Gauge? Sheet metal thickness in the US is specified by gauge number rather than direct measurements. Confusingly, the gauge-to-thickness relationship is different for different metals. A 16-gauge sheet of steel is not the same thickness as 16-gauge aluminum. The tables below give you the actual thickness in inches and millimeters for … Read more
NPS Pipe Dimensions NPS (Nominal Pipe Size) is the North American standard for pipe sizing. Like NPT threads, the “nominal” size doesn’t match the actual dimensions — it’s a naming convention that’s been around for over a century. The OD is constant for a given NPS size. The schedule (40, 80, etc.) determines wall thickness … 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
Standard Hex Nut Sizes These are the basic dimensions for standard hex nuts per ASME B18.2.2. The “width across flats” is what you need for wrench/socket sizing. Nominal Size Threads/in (UNC) Width Across Flats (in) Width Across Corners (in) Height (in) 1/4″ 20 7/16 0.505 7/32 5/16″ 18 1/2 0.577 17/64 3/8″ 16 9/16 0.650 … Read more
Standard Hex Cap Screw Dimensions Hex cap screws (also called hex cap bolts or hex head bolts) are the workhorse fastener of mechanical assembly. This table covers dimensions per ASME B18.2.1 — the data you need for designing bolt holes, counterbores, clearances, and grip lengths. Key Dimensions Explained Width across flats (F) — your wrench/socket … Read more