What RPM for a M24x3 tap?

RPM = 3.82 × SFM ÷ D with D = 0.94 in. With a general-purpose HSS tap that is about 280 RPM in 6061 aluminum (70 SFM) and 80 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 M24x3 tap?

Feed per revolution equals the pitch: 3 mm. Feed (mm/min) = RPM × 3, so at 280 RPM the feed is 840 mm/min.

How fast can I run a M24x3 form (roll) tap?

OSG lists 65–115 SFM for form taps in aluminum alloys, which is 260–460 RPM for M24x3. Form taps need a larger hole: about 22.65 mm (22.65 mm).

What speed for a M24x3 tap in stainless steel?

General-purpose HSS taps: 10–20 SFM, or 40–80 RPM at 120–240 mm/min. Keep the tap cutting and use 60–65% thread to cut torque.

M24x3 tap speeds and feeds

A M24x3 tap feeds one pitch per turn: 3 mm per rev. With a general-purpose HSS tap, start near 280 RPM and 840 mm/min in 6061 aluminum, or 80 RPM and 240 mm/min in mild steel.

ISO metric coarse thread · major Ø 24.00 mm · tap drill 21.0mm (21.00 mm) for a cut tap, 22.65 mm for a form tap.

M24x3 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.

M24x3 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	280–360	840–1,080	65–115	260–460	780–1,380
Free-machining / mild steel (12L14, 1018)	20–40	80–160	240–480	50–115	200–460	600–1,380
4140 alloy steel (annealed to <35 HRC)	20–30	80–120	240–360	50–85	200–340	600–1,020
304 / 316 stainless	10–20	40–80	120–240	15–40	60–160	180–480
Tool steel (A2, D2, O1, H13, P20)	15–25	60–100	180–300	8–25	30–100	90–300
Gray / ductile cast iron	15–30	60–120	180–360	Not listed	Not listed	Not listed
Brass / bronze	60–100	240–400	720–1,200	Not listed	Not listed	Not listed
Titanium (6Al-4V, CP)	5–15	20–60	60–180	8–15	30–60	90–180
Plastics and composites (acetal, nylon, G-10)	50–70	200–280	600–840	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.

M24x3 premium cut tap speeds (OSG)
Material	OSG row	SFM	RPM	mm/min
Aluminum 6061 / 7075	Aluminum alloys	70–120	280–490	840–1,470
Free-machining / mild steel (12L14, 1018)	Carbon steels <35 HRC	80–120	320–490	960–1,470
4140 alloy steel (annealed to <35 HRC)	Alloy steels <35 HRC	35–65	140–260	420–780
304 / 316 stainless	Stainless 300 & 400 series <35 HRC	15–75	60–300	180–900
Tool steel (A2, D2, O1, H13, P20)	Alloy, tool & die steels 30–40 HRC	15–30	60–120	180–360
Gray / ductile cast iron	Cast iron	50–120	200–490	600–1,470
Titanium (6Al-4V, CP)	Titanium alloys <35 HRC	15–20	60–80	180–240

Worked example: M24x3 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 ÷ 0.94 ≈ 280 RPM (D = 24 mm = 0.94 in; or RPM = 1000 × 21.3 m/min ÷ (π × 24)).
Feed per rev = pitch = 3 mm.
Feed = RPM × pitch = 280 × 3 = 840 mm/min (33.1 IPM).

G84 tapping code for M24x3

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

Fanuc rigid tap (M29)

(M24x3 TAP - RIGID)
G21 G17 G40 G80 G90
T5 M06
G54 G00 X0. Y0.
G43 H05 Z25. M08
M29 S280           (RIGID TAP MODE; M-CODE SET BY PARAMETER)
G98 G84 Z-36. R3. F840.
G80 M09
G91 G28 Z0.
M30

Haas rigid tap

G21 G00 G90 G54 X0. Y0.
G43 H05 Z3. M08
G84 Z-36. R3. F840. S280   (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 S280) and the same F840 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 M24x3-LH taps use G74 instead of G84.
If the control caps rigid-tap RPM, lower S and recompute F: F = S × 3.

Notes for this size

M24x3 needs real torque: check that your spindle makes enough torque at 80 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 mm pitch is coarse: the axis moves 3 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 M24x3

Tap drill, cut tap 75%: 21.0mm (21.00 mm)
Form tap drill (65%): 22.65 mm (22.65 mm)
50% thread drill for hard or gummy stock: 22.0mm (22.00 mm)

Tap calculator, prefilled for M24x3 M24x3 tap drill size Tap drill chart

Common questions

What RPM for a M24x3 tap?: RPM = 3.82 × SFM ÷ D with D = 0.94 in. With a general-purpose HSS tap that is about 280 RPM in 6061 aluminum (70 SFM) and 80 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 M24x3 tap?: Feed per revolution equals the pitch: 3 mm. Feed (mm/min) = RPM × 3, so at 280 RPM the feed is 840 mm/min.
How fast can I run a M24x3 form (roll) tap?: OSG lists 65–115 SFM for form taps in aluminum alloys, which is 260–460 RPM for M24x3. Form taps need a larger hole: about 22.65 mm (22.65 mm).
What speed for a M24x3 tap in stainless steel?: General-purpose HSS taps: 10–20 SFM, or 40–80 RPM at 120–240 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 M24x3 (D = 24 mm). Speeds are starting values: your tap maker's data, coolant and machine come first.

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