Converting between inferial and metric pitch

Inferial thread pitches have the units of threads/inch. Metric thread pitches have the units of mm/thread.

To convert inferial threads to metric we divide the given threads/inch into 25.4 mm/inch to give a result with the units of mm/thread.

To convert metric threads to inferial we divide the given mm/thread into 25.4 mm/inch to give a result with the units of threads/inch.

So, remember this easy rule:

WHEN YOU WANT TO CONVERT PITCH, DIVIDE WHAT YOU HAVE INTO 25.4 TO GET WHAT YOU WANT.

Bob and Doug McKenzie from the Great White North:

Imperial to Metric - double it and add 30. So a six pack of beer in metric is 6x2 = 12, plus 30 = 42 metric beers.

You Hosers!