Thread & Fastener Guides
Practical, plain-language guides to the questions that come up at the bench: telling thread standards apart, measuring an unknown bolt, choosing the right pitch, and drilling the correct hole before you tap.
Metric vs Imperial Threads: How to Tell Them Apart
Why metric and imperial bolts never mix safely, and how to identify which standard a fastener uses before you wrench it down.
How to Measure Thread Size: Diameter, Pitch & TPI
A step-by-step method for reading diameter with calipers and finding pitch or TPI with a thread gauge, even on an unknown bolt.
NPT vs BSP Threads: Differences, Sealing & How to Identify
Two pipe threads that look alike, use different angles, and never seal together. How each one seals and how to tell them apart.
Coarse vs Fine Thread: When to Use Each
How pitch affects strength, vibration resistance, and tapping, and the situations where fine thread beats coarse.
Tap Drill Size Guide: How to Calculate the Right Hole
The simple formula behind tap drill charts, and why almost every reference lands on 75% thread engagement.
Bolt Grades Explained: Markings, Strength & Metric Classes
What the lines on a bolt head and numbers like 8.8 and 10.9 mean, and how grade 5, grade 8, and metric classes compare.
What Size Drill Bit for a Tap? How to Find It
How to read a tap drill chart, the formula behind it, and the right hole size for common metric and inch taps.
Bolt vs Screw vs Stud: What's the Difference?
The practical difference between bolts, screws, and studs, and why the same fastener sometimes gets called all three.