FD-M739-E, E-fitment front mech

[Anthony]

I know this is a long-shot, but does anybody happen to know the size of the hex bolt that attaches an FD-M739-E to the boss on the seat tube?
My son commutes on an Orange E4 and has somehow managed to lose the bolt.
The FM is still attached to the bike, of course, by the band that fits between the BB and the BB shell, but it needs the bolt to be rigid enough to work properly.
Obviously, he'll need his father to disassemble the cranks and loosen the BB, as that's how fathers justify their existence, but unfortunately he lives quite far away, so I'm hoping someone can help me, so I can buy a bolt to take to him.
I'm hoping it's a standard bolt, and doesn't vary between frame manufacturers, but I don't know that.
Many thanks

 

[Lucidone]

I'll check when I get home unless someone beats me to it.

 

[Lucidone]

M5 but standard fixing is....non-standard head.


As below a countersunk machine screw should also be okay as protrusion not a problem.


Also you might not have to remove the crank (dependant on what's fitted) - you may be able to get in with a ball end hex wrench or you could undo the chainring to get better access (although if you're going that far it's likely easier to remove the crank).