bolt/thread messurments

[turbojolt]

Just a quick one but m13 or m3 does that relate to the actual thread size don't it?

And if so how do you know what the head size will be?

[joff-turbo-nova]

The M is in relation to the diameter of the thread M3 being small, M13 being bigger.

It can vary on the head bolt size - I know that sometimes M5 and M6 bolts have the same head size - you can vary the head type as well - cap headed bolts which take allen keys/sockets are a good example , or the range of male and female torx (E and T eg E8 or T30)

Hope this helps

Joff

[turbojolt]

So the 3 or 13 whatever it maybe is that a millimeter measurement?

[swedge]

http://www.assistive-technology.ca/studies/wm_nuts.pdf

[turbojolt]

Can't open that on my phone mate will have a look when she gets back with the laptop

[total_vauxhall]

M stands for metric (mm) but m13 sounds a funny size probs find its an m8 (13mm hex head). So u will find with most metric bolts the M size is to the out side of the thread, then you will get a size like 1.25 , 1.50 , 1.75 - this is the thread pitch size ( width between point of thread to point of thread. Hope this helps

[turbojolt]

Yer that's a lot clearer cheers guys was a bit of a noob question but you don't know
if you don't ask lol

[Stuart]

M3 = Metric 3mm bolt thread... It 'could' could have a 5mm head or a 19mm head for all you know/care...
M4 = Metric 4mm Bolt thread
M5 = Metric 5mm Bolt thread and so on

[turbojolt]

As I thought mate cheers