What is a 17/64" drill in decimal and mm?

0.2656 in, or 6.747 mm; nearest number / letter drill: Letter H (0.2660 in, +0.0004 in); nearest metric drill: 6.7 mm (0.2638 in, -0.0018 in).

What RPM for a 17/64" drill in steel?

In low-carbon steel (1018) an HSS 17/64" drill (0.2656 in) runs about 1,290 RPM at 90 SFM; a carbide drill about 4,310 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.

What feed for a 17/64" drill?

About 0.0069 in/rev in mild steel, 0.0063 in/rev in aluminum and 0.0045 in/rev in 304 stainless. At 1,290 RPM that is 8.90 IPM in steel (IPM = RPM × IPR).

What RPM for a 17/64" drill in aluminum?

3,600 RPM with HSS (250 SFM) or up to 8,630 RPM with carbide (600 SFM), feeding about 0.0063 in/rev.

What size is a 17/64" drill?

0.2656 in / 6.747 mm. The nearest other drills are Letter H (0.2660 in), 6.7 mm (0.2638 in), 6.8 mm (0.2677 in).

17/64" drill size

A 17/64" fractional drill is 0.2656 in (6.747 mm).

Decimal inch: 0.2656
Millimeters: 6.747
Nearest 1/64: 17/64" (+0.0000)
Type: fractional drill

Nearest equivalents in other systems

Drills closest to 17/64"
System	Drill	Inch	mm	Difference
Number / letter	Letter H	0.2660	6.756	+0.0004 in
Metric	6.7 mm	0.2638	6.700	-0.0018 in

Speeds and feeds: in mild steel an HSS drill starts at about 1,290 RPM and 0.0069 in/rev (8.90 IPM); in 6061 aluminum about 3,600 RPM.

17/64" drill speeds and feeds by material

Jobber-length twist drill, D = 0.2656 in. RPM = 3.82 × SFM ÷ D, rounded to 10. Feed per rev scales with diameter and material; IPM = RPM × IPR.

17/64" drilling speeds
Material	HSS SFM	HSS RPM	Carbide SFM	Carbide RPM	Feed (in/rev)	HSS IPM	Carbide IPM
Aluminum (6061)	250	3,600	600	8,630	0.0063	22.7	54.4
Brass / free-machining	150	2,160	400	5,750	0.0054	11.7	31.1
Low-carbon steel (1018)	90	1,290	300	4,310	0.0069	8.90	29.7
Alloy steel (4140, annealed)	70	1,010	250	3,600	0.0070	7.07	25.2
Stainless 304	40	580	150	2,160	0.0045	2.61	9.72
Gray cast iron	80	1,150	250	3,600	0.0048	5.52	17.3
Titanium 6Al-4V	25	360	100	1,440	0.0032	1.15	4.61
Plastics (acetal)	300	4,310	500	7,190	0.0041	17.7	29.5

Metric: Vc (m/min) = SFM × 0.3048; feed (mm/rev) = in/rev × 25.4. In steel, 1,290 RPM × 0.175 mm/rev = 226 mm/min.

Worked example: 17/64" drill in 1018 steel

HSS drill in low-carbon steel: 90 SFM.
RPM = 3.82 × 90 ÷ 0.2656 ≈ 1,290 RPM.
Feed for a 0.266 in drill in mild steel ≈ 0.0069 in/rev.
IPM = 1,290 × 0.0069 = 8.90 IPM.

Peck cycle by hole depth

17/64" drill: depth and canned cycle
Depth	Cycle	Peck	Note
3×D = 0.797 in (20.2 mm)	G81 (no peck)	None	Up to 3×D a sharp drill clears chips on its own.
5×D = 1.328 in (33.7 mm)	G73 chip-break	1 × D	Chip-break pecks; full retract if chips pack (soft aluminum, stainless).
8×D = 2.125 in (54 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 17/64" drill

No standard UNC, UNF or metric tap in our tables calls for a 17/64" drill. Use it for clearance, pilot or reamer prep holes.

Nearest drills

Letter H: 0.2660 in / 6.756 mm (+0.0004 in)
6.7 mm: 0.2638 in / 6.700 mm (-0.0018 in)
6.8 mm: 0.2677 in / 6.800 mm (+0.0021 in)
Letter G: 0.2610 in / 6.629 mm (-0.0046 in)

Drill speed calculator, prefilled for 17/64"Drill finder: sizes near 17/64"Fractional drill chart Decimal equivalent chart

Common questions

What is a 17/64" drill in decimal and mm?: 0.2656 in, or 6.747 mm; nearest number / letter drill: Letter H (0.2660 in, +0.0004 in); nearest metric drill: 6.7 mm (0.2638 in, -0.0018 in).
What RPM for a 17/64" drill in steel?: In low-carbon steel (1018) an HSS 17/64" drill (0.2656 in) runs about 1,290 RPM at 90 SFM; a carbide drill about 4,310 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.
What feed for a 17/64" drill?: About 0.0069 in/rev in mild steel, 0.0063 in/rev in aluminum and 0.0045 in/rev in 304 stainless. At 1,290 RPM that is 8.90 IPM in steel (IPM = RPM × IPR).
What RPM for a 17/64" drill in aluminum?: 3,600 RPM with HSS (250 SFM) or up to 8,630 RPM with carbide (600 SFM), feeding about 0.0063 in/rev.
What size is a 17/64" drill?: 0.2656 in / 6.747 mm. The nearest other drills are Letter H (0.2660 in), 6.7 mm (0.2638 in), 6.8 mm (0.2677 in).

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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