Tap and Die

[Daxin]

I'm a little confused about this whole Tap and Die thing. I'm trying to use a metric 8mm with a 1.25 thread pitch and I'm not certain as to what drill and tap I'm suppose to use.

I've search and found topics, but I'm at awe as to what all those numbers represent.

Some help on this topic would be greatly appreciated.

Thanx

[RickDaTuner]

8mm is the size of the bore and 1.25 is the angle of with the threads are,

thats a pretty Big bolt, if i might add

edit, sorry im not being much help, i should really stop skimming through post's and then posting myself

[78si]

For metric:
bolt diameter- thread pitch= drill size

8mm -1.25mm= 6.75mm

[tsi_neal]

its M8 x 1.25 pitch, M8 is the diameter of the bolt and 1.25 is the measuremnt of the pitch.

if thats the die you need then the tap will be exactly the same.

[Daxin]

OOps, I meant M8 is the size.

What about the drill size?

[RickDaTuner]

M8 if i am not mistaken is the grade of the bolt, is that what is stamped on the top?

messure the thickness of the bolt and wich will be the corisppnding tap, and mesure the pitch with is the distance between the threads and then find the tap to match also

[RickDaTuner]

http://euler9.tripod.com/bolt-database/


here is a link to try and help you sort things out

[tsi_neal]

Originally posted by RickDaTuner
M8 if i am not mistaken is the grade of the bolt, is that what is stamped on the top?

messure the thickness of the bolt and wich will be the corisppnding tap, and mesure the pitch with is the distance between the threads and then find the tap to match also

MX (M6, M8, M10, M12, etc) is the size, the grade is stamped to the top, 8.8 is a medium grade bolt, higher grades are stronger and lower grades are weaker rember that the grade is the bolts tensile strength (when it would break with a pulling force, but the higher the grade also the more brittle the bolt so it will usually break under sheer loads instead of bending.)

Back on topic, my drill set it SAE so all i do is pick the closest size to the shaft of the bolt inside the threads, if you have to go a tiny bit to big on the drill bit, if its to small and hard material good luck taping it. (and even better luck getting the broken tap out)