Quick Q. re screw heads eg derailleur mech stop screws...

[Brucey]

....When I was a kid, I remember my Dad using one of those. Our Vacuum cleaner (Hoover - prob 99% of vacuum sales then ) wasn't working. Dad took the front off the plug and checked the 'wire' side of the live with the screwdriver gadget - it showed as live. He switched off the socket and tried another fuse. The Hoover worked. So, it seems the screwdriver gave a false- positive (no pun intended) reading...... That's, of course, better than a false negative!

IME this can easily happen if the 'neutral' connection is bit floaty.

[tubby885]

Pozidrive/Philips type screws are horrible One of the worst designs ever.I replace them with hex socket head screws . . .

[freiston]

Pozidrive/Philips type screws are horrible One of the worst designs ever.I replace them with hex socket head screws . . .

I think a big part of the problem with them is people using the wrong type and/or size of driver for the screw (not "one . . . design" but two different designs). The problem with hex socket screws is that the screw size and head style (especially countersunk) often limits the socket to a small size, which can cause problems too.

[Brucey]

.....(not "one . . . design" but two different designs)......

AFAIK there are at least three different designs, ie. it is probably a lot worse than you think.

[freiston]

Yeah, I thought that as soon as I posted (we've mentioned at least three in this thread ) but I said two because tubby885 referenced two specifically and then referred to them as one design.