Screwing

[derekbell]

I have power screw bits marked PH and PZ, whats the difference, and which one do I use for screwfix scrws which have a 'Prodrive' marking.

 

[2scoops0406]

PH are philips, PZ are pozidrive. Prodrive and pozi drive are compatible. Do not use Philips bits for pozi's or pro's, and vice versa.

 

[derekbell]

Thanks Eddie M, I guess the screw with a cross in the head is Philips and the ones with a cross and 4 little indentations are Pozidrive. Whilst my screw bits are named PH or PZ, my screwdrivers are not, any easy way of identification?

 

[2scoops0406]

Yes, the ones with a simple cross on them are philips, the ones with the small indentations are pozi's. You can tell from your screwdrivers by looking at the tip. If it is simply a cross then it's a philips, if in between the cross there are "shoulders" then its a pozi. Also, you can pretty easily tell if it fits the screw or not.

I reckon, and I speak as a DIY'er, that this must rate as one of the most common DIY problems, trying to tighten a screw with the wrong screwdriver. Ends up in the fastening being insecure, and the screw head well and truly mashed.

 

[masona]

Pozidrive drivers and screws differ from the Phillips screw and screwdriver system. The Pozidrive is designed to perform better with powered screwdrivers and does not “torque out” as easily as the original Phillips screw system.
The Phillips screwdriver should not be used with a Pozidrive screw, and the Pozidrive screwdriver should definitely not be used with a Phillips head screw. Damage to the screw and bit can result.

 

[big-all]

just to add the pz2[pozzi ] bit fits imperial sizes from 6 to 10 [usualy silver]
and metric from 3.5mm to 5mm[usualy gold or yellowish]
this comment refers to wood srews so the pz2 will cover 95% of your needs

 

[derekbell]

What a wonderful Forum, my grateful thanks to all the screwers!

 

[derekbell]

Just to add to the confusion. I have a box of screws which state size 8 1.5 inches. (great 'cos my plugs say use size 8 screws and a 5/5.5 drill).

I buy some more and the box states 4 x 40mm, what happened to the '8', how would I know that this is supposed to be an '8' screw thickness.
Then some Plasplugs say use a number 7 dill, nothing about mm size.

Is it all a conspiracy?

 

[2scoops0406]

Yeah, it's confusing because the sizes are a mixture of guages, imperial and metric, which doesn't really help much.

 

[big-all]

ok approximate comparison only imperial[inches ]usualy silver
4-/--6--/--7-/--8-/-10-/-12 relate to
3-/-3.5-/-4-/-4.5/--5-/--6 metric normaly gold or yellowish

if the box mentions mm its metric if it mentions inches its imperial