Busted heads and furry fixings

[duncan]

Over the years, whilst working on old cars and bikes, I’ve come to hate Philips [slot headed] fixings with a vengeance, it’s that sinking feeling of knowing that you will round the head off before it will screw out.

New to me, is that the Philips headed fastener was doing just what it was designed to do, as a drive system it was designed to ‘cam out’ or extract under torque, such that the original monkeys couldn’t over-tighten and strip the fixing. Good news for box fresh components going in, bad news for rusty, furry fixings not wanting to come out.

New to me also and the reason for the post; is that the OEM slot headed fixings on Hondas are NOT Philips but are manufactured to a JIS [Japanese Industrial Standard] form.
JIS for slot headed screws looks like Philips but are not, the root between the drive is a different, deeper profile and was designed to lock and not to ‘cam out’.
See the attached detail spec.
JIS slot heads should [may?] be marked with a dimple to identify them, [check the door latch screw heads and a dimple stamping is just about visible].

Thus the following scenarios exist,
Philips screwdriver, Philips screw, designed to work together, designed to disengage under load. If it’s old and furry and the head strips – it’s what science intended.
JIS screwdriver, JIS [as Honda OEM] screw, designed to work together, designed to be able to take full torque and to give a Zen like sense of nirvana.
JIS screwdriver, Philips screw, will work together, should be better than Philips/Philips.
Philips screwdriver, JIS screw, will not properly work as the screwdriver cannot get a full face of surface of contact and can and will damage the softer fixing.

How to get JIS screwdrivers - with difficulty; as, save for Japanese companies, the world doesn’t readily accept they exist, let alone for the last 50 years.

Easiest and cheapest – try the slotted screwdriver in the toolkit - honest.
Put a new Philips screw in a vice and then try to turn it with a standard Philips screwdriver then try with the one from the toolkit, totally different feeling the Honda one does not try to slip.
Replacement screwdriver blade from HUK part no 89102-538-000 yours for £2.30!

From elsewhere, try Vessel or Hogan as [Japanese] manufacturers, the nicest I’ve come up with is Vessel 980 series Megadora that is also is an impact driver. See either www.tradesmanchoice.com or
http://www.ebay.co.uk/itm/Vessel-980...item2584c2b1bd

That's the Christmas present for the wife solved then.
Duncan