Metric fine

M48 × 3.0

Tap drill 45 mm for a M48 × 3.0 thread — major Ø 48 mm, pitch 3 mm (8.47 TPI).

Tap drill
45 mm
45 mm · ≈77% thread

Profile

Thread form & key diameters

Major Ø 48 mmP 3 mm60°Minor Ø 44.319 mm · Pitch Ø 46.052 mmM48 × 3.08.47 TPI · 60° form

Dimensions

DesignationM48 × 3.0
Major (outside) diameter48 mm · 1.8898"
Pitch3 mm · 8.47 TPI
Pitch diameter46.052 mm · 1.8131"
Minor diameter (external)44.319 mm · 1.7449"
Minor diameter (internal)44.753 mm · 1.7619"
Recommended tap drill45 mm · ≈77% thread
Clearance holeClose 50 · Normal 52 · Loose 56 mm
Hex head (across flats)75 mm
Socket key (across flats)36 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 8.81603.6 mm²697.55 kN6696.5 N·m
Class 10.91603.6 mm²998.22 kN9582.9 N·m
Class 12.91603.6 mm²1166.59 kN11199.3 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 M48 × 3.0?

For a M48 × 3.0 thread, drill the hole with a 45 mm tap drill (45 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 48 mm and a pitch of 3 mm (8.47 TPI).

To pass a M48 × 3.0 bolt through a part rather than thread it, use a clearance hole: Close 50 · Normal 52 · Loose 56 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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