Is this tap drill chart enough for production drawings?

Use it as a planning reference only. Final tap drill, thread class, clearance, and hardware choices should be confirmed on the drawing and reviewed for material thickness, fastener engagement, and shop process.

What should I include in a FortiFab RFQ when a part has tapped holes?

Include the thread callout, quantity, material, thickness, finish, whether the hole is tapped or clearance, and any PEM or inserted hardware requirements. A DXF, STEP, and PDF drawing package is best.

Can FortiFab help with sheet-metal hardware decisions?

Yes. FortiFab can review bracket, panel, enclosure, and assembly drawings for manufacturability, including hole sizes, hardware access, tapping suitability, and inserted fastener options.

Tap drill chart

Metric and imperial tap drill lookup for fabrication drawings

Use this chart to check common tap drills, decimal equivalents, and clearance holes before sending a bracket, panel, enclosure, or fabricated assembly to FortiFab for review.

Tap drill and clearance lookup

Tap size	Thread	Tap drill	Decimal	Metric equivalent	Close clearance	Free clearance	Typical use
M3 × 0.5	Coarse	2.5 mm	0.0984 in	2.5 mm	3.2 mm	3.4 mm	Small covers, brackets, and light hardware
M4 × 0.7	Coarse	3.3 mm	0.1299 in	3.3 mm	4.3 mm	4.5 mm	Common small machine screw size
M5 × 0.8	Coarse	4.2 mm	0.1654 in	4.2 mm	5.3 mm	5.5 mm	Panels, covers, and small mounts
M6 × 1.0	Coarse	5.0 mm	0.1969 in	5.0 mm	6.4 mm	6.6 mm	Frequent enclosure and bracket fastener
M8 × 1.25	Coarse	6.8 mm	0.2677 in	6.8 mm	8.4 mm	9.0 mm	Heavier brackets and equipment mounts
M10 × 1.5	Coarse	8.5 mm	0.3346 in	8.5 mm	10.5 mm	11.0 mm	Frames, guards, and heavier assemblies
M12 × 1.75	Coarse	10.2 mm	0.4016 in	10.2 mm	13.0 mm	13.5 mm	Large mounting points and structural hardware
M16 × 2.0	Coarse	14.0 mm	0.5512 in	14.0 mm	17.0 mm	17.5 mm	Heavy industrial mounting hardware
#6-32 UNC	Coarse	#36	0.1065 in	2.71 mm	#27	#25	Small covers and electronics-style hardware
#8-32 UNC	Coarse	#29	0.1360 in	3.45 mm	#18	#16	Light panels and brackets
#10-24 UNC	Coarse	#25	0.1495 in	3.80 mm	#9	#7	General sheet-metal hardware
#10-32 UNF	Fine	#21	0.1590 in	4.04 mm	#9	#7	Fine-thread hardware where vibration matters
1/4-20 UNC	Coarse	#7	0.2010 in	5.11 mm	F	H	Common bracket and enclosure fastener
1/4-28 UNF	Fine	#3	0.2130 in	5.41 mm	F	H	Fine-thread quarter-inch hardware
5/16-18 UNC	Coarse	F	0.2570 in	6.53 mm	P	Q	Medium-duty mounting points
3/8-16 UNC	Coarse	5/16 in	0.3125 in	7.94 mm	25/64 in	13/32 in	Equipment mounts and heavier guards
1/2-13 UNC	Coarse	27/64 in	0.4219 in	10.72 mm	17/32 in	9/16 in	Large industrial mounts

Reference values are common shop-planning sizes. Confirm the final hole callout, thread class, depth, fastener, and tolerance requirements on the drawing.

Tap drill chart FAQs

Common questions about using tap drill and clearance-hole references in fabrication RFQs.