Socket Cap Head Screws

[fbg40]

Quick question for all you mechanics out there - is there an easy way to tell what gauge a socket cap head screw is please ? I need to replace 4 and cannot tell whether they are M6, M10 or whatever. Any help would be greatly appreciated. Just for info, the head diameter is 10mm.
FBG40

[Buenchico]

>>> the head diameter is 10mm

As I read this, that means that it's M10:
https://www.quora.com/How-do-you-differentiate-between-M8-M10-and-M12-bolts

[nescio]

M10 is the thread size, approx. 10mm diameter, so the head will be larger. Can you not remove one and measure the shank diameter?

[fbg40]

Thanks for the quick response folks, will have to measure the shank diameter.
FBG40

[sddsddean]

IIRC , an M10 bolt requires a 13mm socket and a M6 bolt requires a 10mm socket...but I could be wrong!!

[alavahalf]

Right enough .. the thread diameter is determined by the number following 'M'.
Every day of the week I use M6 socket cap head screws and the are tightened and slackened using a 6mm hexagon wrench .. not a socket in sight!

[fbg40]

Thanks again for the info - much appreciated.
FBG40

[johnk]

They're probably M6 but you'll need to measure the diameter of the thread. M6 is slightly less than 6mm diameter

[fbg40]

Johnk
Measured as you suggested, just about 6mm. Thanks for your help.
FBG40