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Tuning Guide

What’s The Difference Between a Phillips and a Pozidrive head on a typical screw?

By Mark Harper 11th January 2023

When you purchase self-tapping screws or machine screws from Rooster, make you you use the correct screwdriver for the job....

A typical Rooster pan headed self-tapping screw as used in the ILCA/LASER. (Pozidrive head)

 

SELF TAPPING SCREW GAUGE 10 X 1.5" POZI PAN HEAD - LASER/ILCA SCREW - A4 STAINLESS STEEL

A typical Topper machine screw (Pozidrive head)

A TOPPER Y15 TRAVELLER CLEAT SCREW - SINGLE - A4 STAINLESS STEEL

The image below highlights the difference on the screwdriver head, which corresponds with the difference in the screw recess pattern.

(And just so you know, whilst we use the common UK spelling Pozidrive, Pozidriv is actually the original brand that the term derived from).

Phillips heads have a tapering recess that is designed to “cam out” or slip under heavy torque, to prevent the head from being torn off the screw – screws with no heads are a nightmare to remove!

As you can see the splines on the head of the Phillips screwdriver also taper in at the tip to fit correctly into the recess on the screw head.

On a Pozidrive screw head, the recess is parallel rather than tapered, to enable higher levels of torque to be used without the risk of slippage – this makes it ideal for use with power tools. The diagram shows that the splines of the Pozidrive screwdriver are parallel all the way to the tip, with no taper. For ease of identification, Pozidrive screws always have two diagonal lines on the screwhead intersecting the cross.

If you have no other option then you can use a Phillips screwdriver on a Pozidrive screw for low torque applications, but there is always a risk of damaging the head.

You cannot use a Pozidrive screwdriver on a Phillips screw as it will not fit all the way into the recess – it will only damage the screw head.

A typical PZ screwdriver shown above.

Typical valley cleat fitting, using 2 no. Pozidrive self-tapping screws to attach.

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