How often to replace PZ2 bit: when the tip is done

The hinge screw has started to shine, the clutch is still on a low number, and the same PZ2 has sat in the chuck since the last flat-pack. That is the usual moment the question of how often to replace a PZ2 bit turns up. There is no calendar answer. The tip tells you. When the corners are rounded, or the bit climbs out of a screw that was sound a moment ago, that bit is finished.

A run of 4 mm woodscrews will wear a tip faster than an afternoon of cam locks. BuildWiz, a UK bit guide, does not publish a life in screws. It does treat PZ2 as the bit for ordinary woodscrews of about 3.5–5.0 mm, which is why that size disappears first. Keep a spare of it. A new 100-piece case will not put the corners back on the bit already in your hand.

In short

Replace the PZ2 when the tip is rounded or it cams out of a fresh screw. There is no reliable screw-count, and a forum story of a morning versus half a dozen screws is someone else's report, not a service interval. A pack of that one size is often the saner buy once the other drives are already in the case.

There is no honest screw-count

BuildWiz's guide leaves the gap in the open: there is no reliable figure for how many screws one bit survives. The same page records a forum anecdote in which one bit lasted a morning and another managed about half a dozen screws. That range is someone else's report of two jobs, not a replacement interval. Turning it into a rule to change the bit every morning would invent a figure the source does not give.

The variables stack, which is why a single count never settles. A long screw in oak asks more of the tip than a short chipboard screw in a wardrobe. A high clutch, a fast speed, and a bit that is not square to the head all chew the corners. So does a screw already marked by the wrong drive. If those heads were Phillips screws driven with a Pozidriv bit, the wear came from the mismatch.

Do not plan a job on the idea that this PZ2 has a set number of screws left. Do not keep a bit you have used twice if those screws have already rounded the end. A tip that still seats in a fresh recess, and stays seated, is not scrap because the plating looks dull. These sources publish no wear percentage, and this page will not invent one.

The tip tells you

Change the bit when the tip is rounded, or when it cams out of a screw that still has a clean recess. Accu's note on cam-out is the mechanism: a worn or undersized tip slips. The ribs should drop into the cross and the tick marks and sit without rocking. When the corners have gone, the bit sits shallow, climbs under load, and the head shines where the steel skates.

Look at the spare before you blame the screw. Hold the used PZ2 next to the unused one under a lamp. The worn tip is blunter at the end, and the flanks are rounded off. If the spare seats and the old bit rocks in the same head, the old bit is finished. More trigger pressure polishes the recess. It does not restore the corners.

Check the match before you throw a sharp bit away. A PZ2 in a PZ1 or PZ3 head, or a Phillips bit in a Pozidriv screw, cams out while the tip is still new. BuildWiz notes that mismatch, and the size has to be right once the family is right. Tick marks mean Pozidriv. A plain cross is Phillips. The difference is on the Pozidriv and Phillips page, and seat, angle and clutch are on how to use screwdriver bits. A new PZ2 that still jumps out of a tick-mark head is a setup problem, not a worn bit.

Why PZ2 disappears first

PZ2 does the work you actually do. On the BuildWiz table, which is their guide and not a British Standard, woodscrews of about 3.5–5.0 mm take a PZ2. A 4 mm woodscrew usually sits in that band unless the box prints another size. Their pointer for PZ3 starts at about 6 mm. In a cupboard of shelves, skirting and flat-pack, that tip sees every Saturday.

PH2 does not wear at the same rate unless you drive as many Phillips screws. Board screws are often Phillips when the box says so, so plasterboard blunts the PH2 while the PZ2 sits idle. Deck screws are often Torx, and neither cross fits that star. The rate follows the boxes you open. One of each size is a catalogue, not a match for a drill that lives on one recess.

Listings recorded on amazon.co.uk on 15 October 2026 show the practical answer. The Bosch 32-piece extra-hard set, model 2607017319, includes two PZ2 and two PH2. The Faithfull 61-piece set includes three of each. A Bahco 100-piece reviewer wanted more than one PZ3. Amazon Basics names Phillips, slotted and Torx, and does not name Pozidriv. Duplicates help only when they match your screws. The buying guide sets that against piece count.

Replace the size, not the case

One rounded PZ2 is not a reason to retire the Torx bits, the holder and the case. If the second PZ2 is still sharp, put that one in the chuck and keep the blunt one out of the holder. When both copies are rounded, buy another of that size and leave the rest of the set alone. A bit that arrived already rounded, or snapped on the first screw, is a returns question, not a wear interval.

A new case earns its place when the lid no longer latches, several sizes are rounded, and the steel has rusted in a damp garage. Faithfull reviewers warn of rust if that set is left damp, and some call the tips average. It was about £8.99 on 15 October 2026, rated 4.6 from 240 reviews. The three PZ2 bits are why it is worth a look, and the comments on average tips are why you should expect to replace them sooner.

The Bosch 32-piece extra-hard set was about £8.36 that day, rated 4.7 from 26,022 reviews. It is the top pick in our screwdriver bit set comparison for a first combi drill. The listing describes drill drivers, not an impact rating. One review says the PH2 bits break quite easily, and the plastic case is easy to crack. Two PZ2 bits at that price are useful. They are not a promise the tip will not round, and a heavier case does not add life to the size you use.

A pack of one size

Bosch Professional's GB pages sell extra-hard PZ bits in packs of 25. You replace a size, not a whole set. A DeWalt 25-piece PZ2 impact pack of the kind Elliotts lists is the same habit, useful when PZ2 is most of the week, as on a kitchen fit.

A single-size pack is the wrong buy if you still need PH2, Torx and a holder. It also fails when the bit you are burning is the wrong family. Buy copies after a matched PZ2 has rounded in clean recesses, not after a Phillips bit has skated in Pozidriv heads all morning.

Impact steel has no screw-count we can quote. A torsion zone takes the blows of an impact driver. A worn tip still slips. On the GEINXURN pack, which names an impact zone and two PZ2 bits at 25 mm and at 50 mm, one review says the edges wore quickly. If tips are snapping, read the impact bits page before you buy a harder box. Leave gas appliances, consumer units, stated torque and stair fixings to the right trade. A fresh PZ2 does not make those safe.

This guide draws on the BuildWiz UK bit guide, Accu's note on cam-out, Bosch Professional GB extra-hard PZ packs, and the amazon.co.uk listings recorded for our bit-set comparison on 15 October 2026. We did not run a wear test, and we do not treat a forum anecdote as a service interval. A qualifying purchase through our links can earn a commission at no extra cost to you.