Why is it so difficult to buy 4mm 'bolts' with hex heads?

Everyone sells Pozi, both countersunk and raised and slotted types too.
And plenty with allen heads.

But for this partially obstructed application, I can only get to the sides
of the head.

--
*Failure is not an option. It's bundled with your software.

Dave Plowman London SW
To e-mail, change noise into sound.