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G3 thread: 87.88 mm × 11 TPI

Threads › G3

G3 is a BSP parallel (G) thread: 87.88 mm major diameter, 11 TPI (2.309 mm pitch), 55° form. Tap drill 85.5 mm.

StandardBSP parallel (G)
Major diameter87.884 mm (3.46″)
Pitch11 TPI (2.309 mm)
Thread angle55°
Minor diameter, bolt84.93 mm
Minor diameter, nut84.93 mm
Tap drill85.5 mm
Usual classA bolt

Minor diameters worked out from the basic profile: major Ø − 1.28065 × pitch.

Open G3 in BenchsmithAdd to order list

Measure it

Bolt: Measure across the crests of the bolt with the caliper jaws. Worn bolts read 0.1 to 0.3 under.

Nut or tapped hole: Measure across the tops of the threads inside the nut or hole with the inside jaws. That is the minor Ø. Worn or oversize holes read a little over.

One size up or down

Got a bolt and no idea what it is? Measure the outside Ø and type it into Benchsmith → Find → Thread.