What is a 35/64" drill in decimal and mm?

0.5469 in, or 13.891 mm; nearest number / letter drill: Letter Z (0.4130 in, -0.1339 in); nearest metric drill: 13.9 mm (0.5472 in, +0.0004 in).

What RPM for a 35/64" drill in steel?

In low-carbon steel (1018) an HSS 35/64" drill (0.5469 in) runs about 630 RPM at 90 SFM; a carbide drill about 2,100 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.

What feed for a 35/64" drill?

About 0.0107 in/rev in mild steel, 0.0102 in/rev in aluminum and 0.0087 in/rev in 304 stainless. At 630 RPM that is 6.74 IPM in steel (IPM = RPM × IPR).

What RPM for a 35/64" drill in aluminum?

1,750 RPM with HSS (250 SFM) or up to 4,190 RPM with carbide (600 SFM), feeding about 0.0102 in/rev.

What tap uses a 35/64" drill?

9/16-24 (form (roll) tap, 65% thread); 1/2-20 (Helicoil / STI insert (1/2-20×1D)).

35/64" drill size

A 35/64" fractional drill is 0.5469 in (13.891 mm). It is the form (roll) tap, 65% thread drill for 9/16-24.

Decimal inch: 0.5469
Millimeters: 13.891
Nearest 1/64: 35/64" (+0.0000)
Type: fractional drill

Nearest equivalents in other systems

Drills closest to 35/64"
System	Drill	Inch	mm	Difference
Number / letter	Letter Z	0.4130	10.490	-0.1339 in
Metric	13.9 mm	0.5472	13.900	+0.0004 in

Speeds and feeds: in mild steel an HSS drill starts at about 630 RPM and 0.0107 in/rev (6.74 IPM); in 6061 aluminum about 1,750 RPM.

35/64" drill speeds and feeds by material

Jobber-length twist drill, D = 0.5469 in. RPM = 3.82 × SFM ÷ D, rounded to 10. Feed per rev scales with diameter and material; IPM = RPM × IPR.

35/64" drilling speeds
Material	HSS SFM	HSS RPM	Carbide SFM	Carbide RPM	Feed (in/rev)	HSS IPM	Carbide IPM
Aluminum (6061)	250	1,750	600	4,190	0.0102	17.9	42.7
Brass / free-machining	150	1,050	400	2,790	0.0084	8.82	23.4
Low-carbon steel (1018)	90	630	300	2,100	0.0107	6.74	22.5
Alloy steel (4140, annealed)	70	490	250	1,750	0.0116	5.68	20.3
Stainless 304	40	280	150	1,050	0.0087	2.44	9.14
Gray cast iron	80	560	250	1,750	0.0088	4.93	15.4
Titanium 6Al-4V	25	170	100	700	0.0051	0.87	3.57
Plastics (acetal)	300	2,100	500	3,490	0.0062	13.0	21.6

Metric: Vc (m/min) = SFM × 0.3048; feed (mm/rev) = in/rev × 25.4. In steel, 630 RPM × 0.272 mm/rev = 171 mm/min.

Worked example: 35/64" drill in 1018 steel

HSS drill in low-carbon steel: 90 SFM.
RPM = 3.82 × 90 ÷ 0.5469 ≈ 630 RPM.
Feed for a 0.547 in drill in mild steel ≈ 0.0107 in/rev.
IPM = 630 × 0.0107 = 6.74 IPM.

Peck cycle by hole depth

35/64" drill: depth and canned cycle
Depth	Cycle	Peck	Note
3×D = 1.641 in (41.7 mm)	G81 (no peck)	None	Up to 3×D a sharp drill clears chips on its own.
5×D = 2.734 in (69.5 mm)	G73 chip-break	1 × D	Chip-break pecks; full retract if chips pack (soft aluminum, stainless).
8×D = 4.375 in (111.1 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 35/64" drill

9/16-24 — form (roll) tap, 65% thread
1/2-20 — Helicoil / STI insert (1/2-20×1D) · tap speeds and feeds

Nearest drills

13.9 mm: 0.5472 in / 13.900 mm (+0.0004 in)
13.8 mm: 0.5433 in / 13.800 mm (-0.0036 in)
14.0 mm: 0.5512 in / 14.000 mm (+0.0043 in)
13.7 mm: 0.5394 in / 13.700 mm (-0.0075 in)

Drill speed calculator, prefilled for 35/64"Drill finder: sizes near 35/64"Fractional drill chart Decimal equivalent chart

Common questions

What is a 35/64" drill in decimal and mm?: 0.5469 in, or 13.891 mm; nearest number / letter drill: Letter Z (0.4130 in, -0.1339 in); nearest metric drill: 13.9 mm (0.5472 in, +0.0004 in).
What RPM for a 35/64" drill in steel?: In low-carbon steel (1018) an HSS 35/64" drill (0.5469 in) runs about 630 RPM at 90 SFM; a carbide drill about 2,100 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.
What feed for a 35/64" drill?: About 0.0107 in/rev in mild steel, 0.0102 in/rev in aluminum and 0.0087 in/rev in 304 stainless. At 630 RPM that is 6.74 IPM in steel (IPM = RPM × IPR).
What RPM for a 35/64" drill in aluminum?: 1,750 RPM with HSS (250 SFM) or up to 4,190 RPM with carbide (600 SFM), feeding about 0.0102 in/rev.
What tap uses a 35/64" drill?: 9/16-24 (form (roll) tap, 65% thread); 1/2-20 (Helicoil / STI insert (1/2-20×1D)).

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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