What RPM for a M30x3.5 tap?

RPM = 3.82 × SFM ÷ D with D = 1.18 in. With a general-purpose HSS tap that is about 230 RPM in 6061 aluminum (70 SFM) and 60 RPM in mild steel (20 SFM). Premium coated taps on a rigid CNC can run faster; see the second table.

What is the feed rate for a M30x3.5 tap?

Feed per revolution equals the pitch: 3.5 mm. Feed (mm/min) = RPM × 3.5, so at 230 RPM the feed is 805 mm/min.

How fast can I run a M30x3.5 form (roll) tap?

OSG lists 65–115 SFM for form taps in aluminum alloys, which is 210–370 RPM for M30x3.5. Form taps need a larger hole: about 28.5 mm (28.50 mm).

What speed for a M30x3.5 tap in stainless steel?

General-purpose HSS taps: 10–20 SFM, or 30–60 RPM at 105–210 mm/min. Keep the tap cutting and use 60–65% thread to cut torque.

M30x3.5 tap speeds and feeds

A M30x3.5 tap feeds one pitch per turn: 3.5 mm per rev. With a general-purpose HSS tap, start near 230 RPM and 805 mm/min in 6061 aluminum, or 60 RPM and 210 mm/min in mild steel.

ISO metric coarse thread · major Ø 30.00 mm · tap drill 26.50 mm (26.50 mm) for a cut tap, 28.5 mm for a form tap.

M30x3.5 tapping speeds by material

Cut tap = general-purpose HSS tap. Form tap = OSG form (roll) taps. RPM rounded to 10; feed in mm/min = RPM × pitch. Start at the low end.

M30x3.5 cut and form tap speeds
Material	Cut SFM	Cut RPM	Cut mm/min	Form SFM	Form RPM	Form mm/min
Aluminum 6061 / 7075	70–90	230–290	805–1,015	65–115	210–370	735–1,295
Free-machining / mild steel (12L14, 1018)	20–40	60–130	210–455	50–115	160–370	560–1,295
4140 alloy steel (annealed to <35 HRC)	20–30	60–100	210–350	50–85	160–270	560–945
304 / 316 stainless	10–20	30–60	105–210	15–40	50–130	175–455
Tool steel (A2, D2, O1, H13, P20)	15–25	50–80	175–280	8–25	30–80	105–280
Gray / ductile cast iron	15–30	50–100	175–350	Not listed	Not listed	Not listed
Brass / bronze	60–100	190–320	665–1,120	Not listed	Not listed	Not listed
Titanium (6Al-4V, CP)	5–15	20–50	70–175	8–15	30–50	105–175
Plastics and composites (acetal, nylon, G-10)	50–70	160–230	560–805	Not listed	Not listed	Not listed

Not listed = no form-tap value in the cited tables (OSG lists no form tap for cast iron; brass and plastics are not in its form-tap table).

Premium coated cut taps on a rigid CNC

OSG's starting speeds for its premium HSS-E cut taps (A-Tap family and the titanium/stainless taps it names) are higher than the general-purpose row. Use them only with that class of tap and rigid tapping.

M30x3.5 premium cut tap speeds (OSG)
Material	OSG row	SFM	RPM	mm/min
Aluminum 6061 / 7075	Aluminum alloys	70–120	230–390	805–1,365
Free-machining / mild steel (12L14, 1018)	Carbon steels <35 HRC	80–120	260–390	910–1,365
4140 alloy steel (annealed to <35 HRC)	Alloy steels <35 HRC	35–65	110–210	385–735
304 / 316 stainless	Stainless 300 & 400 series <35 HRC	15–75	50–240	175–840
Tool steel (A2, D2, O1, H13, P20)	Alloy, tool & die steels 30–40 HRC	15–30	50–100	175–350
Gray / ductile cast iron	Cast iron	50–120	160–390	560–1,365
Titanium (6Al-4V, CP)	Titanium alloys <35 HRC	15–20	50–60	175–210

Worked example: M30x3.5 in 6061 aluminum

Surface speed: 70 SFM (low end of 70–90 for a general-purpose HSS tap).
RPM = 3.82 × SFM ÷ D = 3.82 × 70 ÷ 1.18 ≈ 230 RPM (D = 30 mm = 1.18 in; or RPM = 1000 × 21.3 m/min ÷ (π × 30)).
Feed per rev = pitch = 3.5 mm.
Feed = RPM × pitch = 230 × 3.5 = 805 mm/min (31.7 IPM).

G84 tapping code for M30x3.5

Rigid tapping, aluminum numbers from the example, metric (G21), depth 1.5 × D. Check your control's manual before running.

Fanuc rigid tap (M29)

(M30x3.5 TAP - RIGID)
G21 G17 G40 G80 G90
T5 M06
G54 G00 X0. Y0.
G43 H05 Z25. M08
M29 S230           (RIGID TAP MODE; M-CODE SET BY PARAMETER)
G98 G84 Z-45. R3. F805.
G80 M09
G91 G28 Z0.
M30

Haas rigid tap

G21 G00 G90 G54 X0. Y0.
G43 H05 Z3. M08
G84 Z-45. R3. F805. S230   (NO M03 NEEDED)
(PECK: ADD Q = PECK DEPTH; J2 = RETRACT 2X, SEE SETTING 130)
G80 G00 Z25. M09

Floating / tension-compression holder

Without rigid tapping, run G84 with the spindle on (M03 S230) and the same F805 feed, but hold the tap in a tension-compression holder: it absorbs the overrun when the spindle stops and reverses. Leave the holder room to float at the bottom, so program the depth a little short and follow the holder maker's setting.

Peck tapping (Q) clears chips in deep or blind holes in stainless and 4140; skip it in aluminum unless chips pack.
Left-hand M30x3.5-LH taps use G74 instead of G84.
If the control caps rigid-tap RPM, lower S and recompute F: F = S × 3.5.

Notes for this size

M30x3.5 needs real torque: check that your spindle makes enough torque at 60 RPM (a gear-range spindle may need its low range). Thread milling is often the safer choice in tough material at this size.
A 3.5 mm pitch is coarse: the axis moves 3.5 mm every revolution, so check the machine can hold sync at the IPM shown before raising RPM.

4140 alloy steel (annealed to <35 HRC): Prehardened 4140 (28–32 HRC) is at the top of this band: use the low end and 50–65% thread.
304 / 316 stainless: Work-hardens: never let the tap dwell or rub, and use a tap made for stainless. 60–65% thread cuts torque sharply.
Tool steel (A2, D2, O1, H13, P20): Values are for annealed or prehardened stock. Tap before heat treat whenever you can; hardened tool steel needs a thread mill or a carbide tap.

Hole and tools for M30x3.5

Tap drill, cut tap 75%: 26.50 mm (26.50 mm)
Form tap drill (65%): 28.5 mm (28.50 mm)
50% thread drill for hard or gummy stock: 27.75 mm (27.75 mm)

Tap calculator, prefilled for M30x3.5 M30x3.5 tap drill size Tap drill chart

Common questions

What RPM for a M30x3.5 tap?: RPM = 3.82 × SFM ÷ D with D = 1.18 in. With a general-purpose HSS tap that is about 230 RPM in 6061 aluminum (70 SFM) and 60 RPM in mild steel (20 SFM). Premium coated taps on a rigid CNC can run faster; see the second table.
What is the feed rate for a M30x3.5 tap?: Feed per revolution equals the pitch: 3.5 mm. Feed (mm/min) = RPM × 3.5, so at 230 RPM the feed is 805 mm/min.
How fast can I run a M30x3.5 form (roll) tap?: OSG lists 65–115 SFM for form taps in aluminum alloys, which is 210–370 RPM for M30x3.5. Form taps need a larger hole: about 28.5 mm (28.50 mm).
What speed for a M30x3.5 tap in stainless steel?: General-purpose HSS taps: 10–20 SFM, or 30–60 RPM at 105–210 mm/min. Keep the tap cutting and use 60–65% thread to cut torque.

Nearby sizes

Sources

Productivity Inc. tool catalog, Tech Info - Taps: General Purpose & Other Tap Speeds (pp. 405-416)
OSG USA, A Brand & Premium Tooling Recommendation Guide Vol. 4 (Threading and Drilling), EDP 800313CA-V4, 2026
Haas Automation, G84 Tapping Canned Cycle (Group 09), mill G-code reference
Thread dimensions and tap drills: Machinery's Handbook, 31st ed.; ASME B1.1 Unified Inch Screw Threads.

SFM ranges are copied from the tables above; RPM and feed are computed for M30x3.5 (D = 30 mm). Speeds are starting values: your tap maker's data, coolant and machine come first.

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