What is a 15/16" drill in decimal and mm?

0.9375 in, or 23.813 mm; nearest number / letter drill: Letter Z (0.4130 in, -0.5245 in); nearest metric drill: 23.75 mm (0.9350 in, -0.0025 in).

What RPM for a 15/16" drill in steel?

In low-carbon steel (1018) an HSS 15/16" drill (0.9375 in) runs about 370 RPM at 90 SFM; a carbide drill about 1,220 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.

What feed for a 15/16" drill?

About 0.0123 in/rev in mild steel, 0.0125 in/rev in aluminum and 0.0102 in/rev in 304 stainless. At 370 RPM that is 4.55 IPM in steel (IPM = RPM × IPR).

What RPM for a 15/16" drill in aluminum?

1,020 RPM with HSS (250 SFM) or up to 2,440 RPM with carbide (600 SFM), feeding about 0.0125 in/rev.

What tap uses a 15/16" drill?

1"-8 (form (roll) tap, 65% thread).

15/16" drill size

A 15/16" fractional drill is 0.9375 in (23.813 mm). It is the form (roll) tap, 65% thread drill for 1"-8.

Decimal inch: 0.9375
Millimeters: 23.813
Nearest 1/64: 15/16" (+0.0000)
Type: fractional drill

Nearest equivalents in other systems

Drills closest to 15/16"
System	Drill	Inch	mm	Difference
Number / letter	Letter Z	0.4130	10.490	-0.5245 in
Metric	23.75 mm	0.9350	23.750	-0.0025 in

Speeds and feeds: in mild steel an HSS drill starts at about 370 RPM and 0.0123 in/rev (4.55 IPM); in 6061 aluminum about 1,020 RPM.

15/16" drill speeds and feeds by material

Jobber-length twist drill, D = 0.9375 in. RPM = 3.82 × SFM ÷ D, rounded to 10. Feed per rev scales with diameter and material; IPM = RPM × IPR.

15/16" drilling speeds
Material	HSS SFM	HSS RPM	Carbide SFM	Carbide RPM	Feed (in/rev)	HSS IPM	Carbide IPM
Aluminum (6061)	250	1,020	600	2,440	0.0125	12.8	30.5
Brass / free-machining	150	610	400	1,630	0.0097	5.92	15.8
Low-carbon steel (1018)	90	370	300	1,220	0.0123	4.55	15.0
Alloy steel (4140, annealed)	70	290	250	1,020	0.0128	3.71	13.1
Stainless 304	40	160	150	610	0.0102	1.63	6.22
Gray cast iron	80	330	250	1,020	0.0107	3.53	10.9
Titanium 6Al-4V	25	100	100	410	0.0059	0.59	2.42
Plastics (acetal)	300	1,220	500	2,040	0.0078	9.52	15.9

Metric: Vc (m/min) = SFM × 0.3048; feed (mm/rev) = in/rev × 25.4. In steel, 370 RPM × 0.312 mm/rev = 116 mm/min.

Worked example: 15/16" drill in 1018 steel

HSS drill in low-carbon steel: 90 SFM.
RPM = 3.82 × 90 ÷ 0.9375 ≈ 370 RPM.
Feed for a 0.938 in drill in mild steel ≈ 0.0123 in/rev.
IPM = 370 × 0.0123 = 4.55 IPM.

Peck cycle by hole depth

15/16" drill: depth and canned cycle
Depth	Cycle	Peck	Note
3×D = 2.813 in (71.4 mm)	G81 (no peck)	None	Up to 3×D a sharp drill clears chips on its own.
5×D = 4.688 in (119.1 mm)	G73 chip-break	1 × D	Chip-break pecks; full retract if chips pack (soft aluminum, stainless).
8×D = 7.500 in (190.5 mm)	G83 full retract	0.5-1 × D, shrinking with depth	Retract to clear chips; reduce feed ~10-20% past 5×D.

Taps that use a 15/16" drill

1"-8 — form (roll) tap, 65% thread · tap speeds and feeds

Nearest drills

23.75 mm: 0.9350 in / 23.750 mm (-0.0025 in)
24.0 mm: 0.9449 in / 24.000 mm (+0.0074 in)
23.5 mm: 0.9252 in / 23.500 mm (-0.0123 in)
59/64": 0.9219 in / 23.416 mm (-0.0156 in)

Drill speed calculator, prefilled for 15/16"Drill finder: sizes near 15/16"Fractional drill chart Decimal equivalent chart

Common questions

What is a 15/16" drill in decimal and mm?: 0.9375 in, or 23.813 mm; nearest number / letter drill: Letter Z (0.4130 in, -0.5245 in); nearest metric drill: 23.75 mm (0.9350 in, -0.0025 in).
What RPM for a 15/16" drill in steel?: In low-carbon steel (1018) an HSS 15/16" drill (0.9375 in) runs about 370 RPM at 90 SFM; a carbide drill about 1,220 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.
What feed for a 15/16" drill?: About 0.0123 in/rev in mild steel, 0.0125 in/rev in aluminum and 0.0102 in/rev in 304 stainless. At 370 RPM that is 4.55 IPM in steel (IPM = RPM × IPR).
What RPM for a 15/16" drill in aluminum?: 1,020 RPM with HSS (250 SFM) or up to 2,440 RPM with carbide (600 SFM), feeding about 0.0125 in/rev.
What tap uses a 15/16" drill?: 1"-8 (form (roll) tap, 65% thread).

Nearby drill sizes

Sources

Machinery's Handbook, 31st ed., Speeds and Feeds for Drilling, Reaming and Threading (Tables 17-23) — HSS and carbide drilling SFM (rounded).
RedLine Tools (Productivity Inc.) catalog p. 340, Cobalt & HSS Drills Speeds & Feeds — feed per rev by drill diameter and material (middle of the catalog range).
ASME B94.11M twist drills: number (#1-#80) and letter (A-Z) drill sizes; drill size reference.

Material feed multipliers (aluminum 1.3×, brass 1.1×, 4140 0.85×, stainless and titanium 0.7× the mild-steel feed) are JobLine estimates. Peck guidance is JobLine shop practice. Use your drill maker's data first.

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