Metric fine

M24 × 1.5

Tap drill 22.5 mm for a M24 × 1.5 thread — major Ø 24 mm, pitch 1.5 mm (16.93 TPI).

Tap drill
22.5 mm
22.5 mm · ≈77% thread

Profile

Thread form & key diameters

Major Ø 24 mmP 1.5 mm60°Minor Ø 22.16 mm · Pitch Ø 23.026 mmM24 × 1.516.93 TPI · 60° form

Dimensions

DesignationM24 × 1.5
Major (outside) diameter24 mm · 0.9449"
Pitch1.5 mm · 16.93 TPI
Pitch diameter23.026 mm · 0.9065"
Minor diameter (external)22.16 mm · 0.8724"
Minor diameter (internal)22.376 mm · 0.881"
Recommended tap drill22.5 mm · ≈77% thread
Clearance holeClose 25 · Normal 26 · Loose 28 mm
Hex head (across flats)36 mm
Socket key (across flats)19 mm

ISO 273 clearance holes (fine / medium / coarse).

Tightening torque estimate

Target preload is 75% of proof load; torque is estimated from T = K · F · d.

Grade / classStress areaPreloadTorque
Class 8.8400.9 mm²174.39 kN837.1 N·m
Class 10.9400.9 mm²249.55 kN1197.9 N·m
Class 12.9400.9 mm²291.65 kN1399.9 N·m
These figures assume a nut factor of K = 0.20 (dry / as-received steel). K captures thread and head friction and can swing torque by 30% or more — a lubricated joint needs noticeably less. Change the lubrication assumption in the bolt-torque calculator.

What tap drill do I need for M24 × 1.5?

For a M24 × 1.5 thread, drill the hole with a 22.5 mm tap drill (22.5 mm — the standard D − P rule) before tapping. That produces roughly 77% thread engagement, the usual target for a strong, tappable hole. The mating bolt has a major diameter of 24 mm and a pitch of 1.5 mm (16.93 TPI).

To pass a M24 × 1.5 bolt through a part rather than thread it, use a clearance hole: Close 25 · Normal 26 · Loose 28 mm.

All values are generated from the standard thread formulas (ISO 68-1 / ASME B1.1) and published standard tables — not hand-entered. See the full reference.

Same diameter

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