What sizes does this cover?

The Socket & Wrench Size pack covers standard metric hex bolts from M3 to M36 and imperial hex bolts from 1/4" to 1-1/2". These are the most common sizes in hardware stores and automotive work.

Are these sizes guaranteed correct?

Sizes are based on ISO and SAE standards for standard hex head bolts and nuts. Actual fasteners vary by manufacturer, grade, and application. Always verify with the fastener when precision matters.

What about Torx, spline, or specialty fasteners?

This tool covers hex head fasteners only. Torx, spline, 12-point, and other drive types are not yet supported.

Can I use the nearest imperial socket on a metric bolt?

In a pinch it may work, but risks rounding the fastener head. Use the correct socket whenever possible. Related values shown are for reference, not substitution.

Will more packs be added?

Yes. Pilot Hole, Tap Drill, and Metric/Imperial conversion packs are planned. The architecture supports new reference sets without changing the app.

#4-40 Tap Drill — #43

The recommended tap drill for a #4-40 thread is #43. Thread engagement: ~75%.

Result

Answer

#43 drill bit (0.089")

Standard

Buy#43 drill bit Tap & drill set Pro tap set

Thread#4-40 UNC

TPI40

Tap Drill#43

Decimal Equivalent0.089"

Thread Engagement~75%

For a #4-40 UNC thread (40 TPI), use a #43 drill bit (0.089" decimal). This targets approximately 75% thread engagement, which is the standard recommendation for most applications.

Note

Reference value from published fastener data. Always verify with the fastener manufacturer for critical applications.

Related Sizes

#6-32 →

About #4-40 Tap Drill

For a #4-40 UNC thread (40 TPI), the recommended tap drill size is #43 (0.089" decimal). This produces approximately 75% thread engagement, which is the industry standard for most applications. Always use a sharp HSS or cobalt drill bit and proper cutting fluid when tapping.

← Look up another thread size