Wera BiTorsion Diamond Bit Pozi #2 25mm
Shattered after 30 screws
Bit purchased to use with a makita 18v impact driver. Used for building stud walls from 3x2 CLS whitewood timber. 5x70mm and 5x100mm goldscrews were used.
Firstly, I fitted the bit directly into the hex shank recess without any kind of adaptor and it kept falling out due to lack of friction. This was a brand new impact driver and all other (cheaper) bits i own fitted snugly. Not only is it annoying to have to keep picking the bit up, but severely reduces productivity if you're up a ladder and have to retrieve it, assuming you can see where it went. Holding the impact driver anything past horizontal and it falls out which is not what you want when paying extra for a product intended to improve upon a basic design and drove me bonkers everytime i wanted to screw downwards.
The next issue was the fact the bit then shattered after driving approximately twenty 5x70mm goldscrews into the stud ends and ten 5 x 100mm goldscrews into softwood joists. Thirty screws in total. (I had even drilled a 4mm pilot hole to 40mm depth to prevent the timber splitting so you could actually argue it actually only managed fifteen screws). I am not ham fisted either.
I then chewed my way through 3 standard bits to finish the job which is exactly why I was keen to to try this diamond bit. I think it's fair to say that the Wera bit gripped well until it shattered and I reckon it would have taken longer to round off had it not shattered, but I never made it that far.
Given the hardened nature of these bits, some will shatter quicker than others so I will buy a couple more. If these bits all fail in a similar short time, it might be better value buying standard bits in bulk and discarding them every 20 screws, or as necessary. I dont quite understand how they have a 2 yr guarantee...
20 Feb 2015
These pozidrive bits are the business, they grip well and last much longer than cheaper bits.
19 Jan 2015
worse bit ever
what a load of rubbish i took out only 100 or so screws out of softwood and the thing is ready for the bit
20 Nov 2014
Decent Diamond Bit
Grips the Screws like nothing else (keeps getting pulled out of the bit holder).
These last for ages, I would say it outperforms and outlasts a cheap bit by a factor of at least 10. Making it pretty good value. Unless you loose it or someone borrows it (they are unlikely to give it back)...
11 Nov 2014