Shop reference tables — tap drills, torque specs, hardness conversions, galvanic pairs. All free, no signup, and they load fast enough to use with a part in your other hand.

These live on our engineering tools site, FicientDesign, where we maintain them alongside a full set of engineering calculators. Bookmark whichever one you reach for most.

Threads and Tapping

Tap Drill Size Chart — UNC, UNF & Metric
Every tap drill size in one table. The one you want bookmarked. 1/4-20 is a #7 (0.201″).
NPT Tap Drill Size Chart
National pipe thread drill sizes — tapered threads have their own rules.
Metric Thread Tap Drill & Clearance Chart
Coarse and fine metric, with clearance drill sizes alongside.
Thread Engagement Length
How many threads you actually need before the joint strips — matters most in aluminum and plastics.

Fasteners and Joints

Bolt Torque Chart — SAE & Metric
Recommended tightening torque by grade, size and lubrication condition.

Materials

Hardness Conversion Chart — HRC, HRB, HV, HB
Convert between Rockwell, Brinell, Vickers and approximate tensile strength, per ASTM E140.

Corrosion and Finishing

Galvanic Compatibility Chart
Which metal pairs corrode when they touch. Check this before you bolt aluminum to stainless.

Seals

O-Ring Groove Chart
Gland dimensions, squeeze and fill for static and dynamic seals.

Electrical

AWG Wire Gauge Chart
Diameter, ampacity and resistance by gauge.

Need the part made, not just the number?

We run CNC machining, fabrication, welding and finishing out of Dallas–Fort Worth. Send a drawing and we will quote it. Request a quote.