regrinding pozi or phillips - angles?

[bugbear]

I have had great success over the years regrinding lovely old straight blade screwdrivers - it's well worth it, since some of the handles are either comfortable, beautiful or both.

But I have some car-boot Pozi and Phillips screwdrivers, of basically good quality, where the ends are a little burred up, but still with plenty of good metal left.

I would like to grind these so the tips are near-perfect again.

Does anyone know the specifications of Pozi and Phillips (size 2 in both, primarily) ?

BugBear

 

[ED65]

I don't believe the exact geometry matters hugely with a Phillips. They're supposed to come to a point but I've filed or ground them straight across and with a slight crown before touching up the flutes and they seem to work equally well either way so the very tip may not matter much. Based on something I read (can't remember where) you actually shouldn't deburr them after reworking the tip as any burr helps them to bite into the screws better.

With Pozidriv I don't think the very tip matters that much either, but the flutes do and if they're basically unharmed I think you could just use your judgement about dressing the tip and it won't affect function much (or honestly at all) since the raised ribs add most of the additional holding power. I don't think it's possible to rework a Pozi tip's grooves in the same way that you can a Phillips, even with a triangular needle file or saw file I don't think you'd have the necessary clearance. Maybe with a feather file?

Anyway, this giant image of a Pozi head from Wikipedia might be of help.

 

[Racers]

Grind the tip back at the existing angle, basicly move the tip up the shaft, don't grind the flats that engage with the screwhead just the end.

Pete

 

[graduate_owner]

If you don't succeed, make them into a fewmore straighf blade screwdrivers.

K

 

[Biliphuster]

Regrind a pozi? Rather you than me.

Do post if you manage it (or not) though.

 

[GLFaria]

Found this at a time I was looking for information on Ph and Pz bits and couldn't download the ISO Standards (unless I paid a lot, of course). Kept it as I thought it might be of use some day . I hope I am not infringing a copyright by posting the picture.
Cyrillic Alphabet, but it's the numbers that matter
I picked it froms: http://www.project-house.by/screw , halfway down the page.

Hope this helps, and good luck, I bet you will need it.