"Torsion" bits for impact drivers

Its worth using decent bits in an ID - however the Wiha or Vera style at a couple of quid a pop from TS / SF etc are usually fine.

I've not actually run a test of how long regular bits last vs the Wera bits vs cost, but I've found that assuming the ID work isn't particularly demanding the regular bits last a fair amount of time.

By demanding I mean lots of driving straight long screws into timber with no pilot holes. Stuff like going through pilot holes into wall plugs is no bother.

I've found you can hear when a bit is going to go soon - the sound changes to a harsher sound. Note I've sometimes had bitholders go too - so worth having some spares of these. (I've not used the high strength bit holders.)

A cheapo Toolsatan No2PZ bit will easily last for a thousand decking screws.

I've also had cheapo bit holders shatter.

Why pilot holes?

So 1970's :-)

Screws like Turbogold et al don't need them.

Fine if you don't want to get them out again, but very difficult to remove.

Why does an impact driver not shake ones hands to bits as you use it?

Brian

I've found they come out just fine with the impact driver.

Cheers chaps, I've not got *that* many to do, and with pilot holes shouldn't be testing anything to destruction ...

Inertia.

ISTR small print on torsion bits also says "must use matching "torsion bit" holder" at £XX pounds extra.... kerching!!

Jim K

I find that very ordinary mild steel ones don't last well, but anything that is a tad harder (and usually TiN coated) seems to last well enough. I bought a box of 15 from SF own brand ones some time back, and they seem to be lasting well.

Because the impact is angular and not linear - so it translates to a torque "kick" rather than a more traditional Cartesian axis vibration, and the inertia difference between the bit and the whole machine is huge, so you hardly feel it on the machine.

I have a 25 pack of De Walt PZ2s for regular stuff, and they're OK, but upgrade to Weras for the hard stuff (unless I can't be bothered to find one - normally cos I've only got a few screws to do). For PZ3s I tend to use the Weras exclusively, cos when I need a PZ3 it's going to need a fair amount of whacking.

I don't use the bits that come with el cheapo drill/bit sets in my impact driver, because they seem to be made of cheese.

Other thing I found an impact driver amazing at was removing slotted steel ordinary steel screws from door hinges - that had been there for half a century plus. And ordinary screwdriver (or more likely me) would have chewed up several of the heads.

I think the wera diamond ones break easily using my one+ impact driver. I started using some cheap toolstation dewaltz ones and they last about as long, because I don't look after them well and lose the damn things.

I have just bought a wera impaktor PZ2 to try.

There seems to be a middle ground where you want something hard enough not to lose shape and have the corners round off, while not being so hard they shatter as soon as you look at them the wrong way. Keeping the bit well engaged in the screw, and not letting it rattle about too much helps as well.

I don't want them to come out :-)

Well, I drilled them anyway. Old felt removed, 32m of battening fixed to shed roof, barge boards raised to match, just waiting for weather to decide what it's going to do before fixing onduline sheets.

The Wickes Ultragold screws use a pozisquare and came with a 'free' bit, which finished the job unharmed, the bit holds the screws very well.