Metric fine

M48 × 2.0

Tap drill 46 mm for a M48 × 2.0 thread — major Ø 48 mm, pitch 2 mm (12.7 TPI).

Tap drill
46 mm
46 mm · ≈77% thread

Profile

Thread form & key diameters

Major Ø 48 mmP 2 mm60°Minor Ø 45.546 mm · Pitch Ø 46.701 mmM48 × 2.012.7 TPI · 60° form

Dimensions

DesignationM48 × 2.0
Major (outside) diameter48 mm · 1.8898"
Pitch2 mm · 12.7 TPI
Pitch diameter46.701 mm · 1.8386"
Minor diameter (external)45.546 mm · 1.7932"
Minor diameter (internal)45.835 mm · 1.8045"
Recommended tap drill46 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 8.81670.8 mm²726.82 kN6977.5 N·m
Class 10.91670.8 mm²1040.1 kN9985 N·m
Class 12.91670.8 mm²1215.54 kN11669.2 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 × 2.0?

For a M48 × 2.0 thread, drill the hole with a 46 mm tap drill (46 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 2 mm (12.7 TPI).

To pass a M48 × 2.0 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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