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View Full Version : Need Help! metric tap M5x.8 More than 1 size?



drhaasmach
09-05-2008, 04:45 AM
I am doing a job coming up with metric tapping. I've found out that M5x.8 comes in 2 different diamaters. Anyone with knowledge about metric tap sizes plz tell me how they tell the 2 apart. I've ordered the wrong one 2x now but found a M5x.8 at the local store that fit but it is cheap. TY

Torsten
09-05-2008, 07:59 AM
Metric sizes are pretty easy, just think in decimal sizes they don't do fractions.
M = metric
first number = diameter O.D. in mm
x = separator between diameter and pitch
second number = pitch from one thread to the next in mm.

M5x.8 is a Thread with 5mm outer dia. and a .8 pitch.
this is the standard Thread often just called out as M5

You may be confusing this with another different Thread there is a M5.5x?

drhaasmach
09-05-2008, 09:13 AM
Ty for the help. I have two different taps that both say M5x.8 and the OD is different. 1 big 1 small. ?

rk176
09-05-2008, 10:03 AM
Ty for the help. I have two different taps that both say M5x.8 and the OD is different. 1 big 1 small. ?
Use the one from the local store .I think your large one will be a helicoil tap for use wth thread repair inserts

drhaasmach
09-05-2008, 10:25 AM
Yep that was it i've been ordering sti helicoil taps. Ty, im a noob live and learn.