Screwed or screwed?

[Mosey]

Why is it that none of my various phillips screwdrivers fit that small phillips screw that is very tight in it's hole?
Is there a standard for the angle of the tip of these drivers?
I have some Snapon, Wiha, and other high quality drivers, none of which will properly fit into the head of some screws.
What is the angle?

 

[mcostello]

Possibly the small diameter in the middle of the flats is too big and needs worked down.

 

[bhamm1]

Are you trying Metric drivers on standard screws? There is quite a difference between the two. You should have both Metric and American, plus probably other measurement, drivers

 

[MuellerNick]

I have my doubts wether there are metric or imperial sizes for Philips heads.
My bet is, that those that don't fit your Philips screwdrivers are simply Pozidriv heads. They are different. Easy to distinguish because they to have a slight cross embossed. Rotated 45° to the cross for the screwdriver.


Nick

 

[kcmillin]

There a a few different type of "Philips" screwdrivers. If the screwdriver you are using has a blunt tip than it is a philips, of which you will need a different size for different screws. The other type of "Philips" is called a Reed & Prince, which has a sharp pointed tip, and is not actually a philips, although it is often referred to as one.

Look here for all the different types
http://en.wikipedia.org/wiki/List_of_screw_drives

Kel

 

[ninefinger]

My bet is, that those that don't fit your Philips screwdrivers are simply Pozidriv heads. They are different. Easy to distinguish because they to have a slight cross embossed. Rotated 45° to the cross for the screwdriver.


Nick

+1 MuellerNick
Yep - PoziDriv would be my guess. In addition to the screw head having the added markings, the tip angles on the screwdriver head are different than Phillips, and there are added ridges on the pozidriv tip.
Images of the screw head difference:

Mike

 

[Tin Falcon]

I have some Snapon, Wiha, and other high quality drivers, none of which will properly fit into the head of some screws.

like others have mentioned there are several types of "cross point " screws, and hence several sets of specifications.You have quality tools so expect them to be spot on. so you either have a cheap screw that was not made to proper specs or you are attempting to mix types.
Also these screws and bits come in specified sizes like P1,p2,p3 ... so there could simply be a size mismatch.
Details details
Tin

 

[MachineTom]

If the screwdriver seems that the angle is too steep, then the screw is a JIS Japanese Industrial Standard, you have to look around but they are available. sized like a phillips 00, 0, 1, 2. I found a set an got there don't remember where.

 

[rake60]

There are too many different styles of Phillips screw configurations to mention.
I decent security bit set is sure to cover all of them.
These sets can be expensive, but they do not need to be.

I purchased mine from Northern Tool for $12 USD.

Rick

 

[Tin Falcon]

I agree with rick a security bit set will give lots of choices. I have one from harbor freight IIRC 7 bucks on sale. the problem is not confined to cross point. Gunsmiths have to deal with many sizes of slotted screws. IIRC gun smith sets have a couple dozen sizes of various widths and thicknesses. Many of the old smiths would grind there own to fit. I have been known to grind the tip off a cross point apex to get a better grip on an aircraft screw. And have turned a hex bit into a slotted bit in a pinch.
Tin

 

[Mosey]

Well, there is a great deal of valuable information in these posts, and I thank you for the help.
The screws in question are all Phillips. None are Posidriv or other types.
The various drivers are all Phillips, so marked by their quality makers.
The key piece of intelligence here is the reference to JIS, as the screws in question are from a Japanese engine, and they are not very hard. They easily become buggered up, so need to be replaced. I suspect that may be intentional, to keep you from buggering the block or head of the engine.
I am now researching whether Wiha makes Japanese form drivers. Their metric and Imperial drivers are the same. The smallest size ones are actually both systems in 1 driver, because they are so close in dimension.

 

[Tin Falcon]

JIS Standard screw divers $17.99l

do a Google search for JIS standard screwdrivers they are out there.
Tin

 

[BAH101]

You could try putting a dab of valve laping compound to the tip of your screwdriver. I've done that before to remove Phillips screws with damaged heads. Give the screwdriver a little extra holding power.

 

[Mosey]

Very clever. I'll give it a try.
In the meantime, I am replacing the screws with hex socket head ones.

 

[skyline1]

Hi Mosey

I've had the same problem with Japanese engine screws they are very soft and just sort of round off when you try to remove them. As you say it might be deliberate. The best way I've found to get 'em out is the same way they put 'em in with an impact driver. Or if you have some of those through shaft drivers an old mechanic's trick is to hit the end with a hammer and twist at the same time.

Regards Mark

 

[Tin Falcon]

there is always the superglue trick glue the screw to the tip. when it is out heat the screw to denature the glue.
tin

 

[starnovice]

I had not heard of the superglue trick. I will add that to my that to my list of things to try when :fan: . I suppose green locktite would work well too.

Thank Tin

 

[Mosey]

What I've found is my English cabinet-makers screwdrivers, with the egg-shaped hornbeam handles fit these fasteners perfectly! These are inexpensive, and came in sets from Garrett Wade many years ago. They are better than all of the high precision forged German driver bits, Wiha, Snapon, Black & Decker, etc.
Go figure?:wall:

 

[Tin Falcon]

When I worked at the local air national guard base full time I was trained as machinist welder and worked in aircraft structural repair/corrosion control. One of my jobs was removing fasteners after the "Screw chiefs" buggered them up. And yes I use the term "screw chief " with a certain affection since my brother is still there working as a crew chief he has been at it for IIRC about 28 years now. So IMHO I got pretty good at removing difficult to remove screws . The fun ones were the ones co-workers drilled and broke off the easy outs in then looked to me for a bail out. but I have my tricks. and got them out. I never resorted to the super glue but it apparently works. Lets say EL Brutus was my friend. A great tool but dangerous in the hands of an idiot.

.browntool.com El Brutus these are great for aircraft work but IMHO abit too pricey for home shop and not a lot of need. you can buy a lot of superglue and scews for $300.
Tin

 

[goldstar31]

I still have a cow mouthed chisel. The worst thing recently was the countersunk screws in a wood shredder. They seem to be impervious to heat or 'Plus Gas, WD40 or whatever' and seem to fret solid with the impacts on the cutting blades which I can only describe as 'Brute force and bl**dy ignorance' devices. I've had a go at two of mine and one which lived in sea water and a mixture of date palms.

It needs a very steady hand and a keen eye to create a kerf to get some bite to drift the screws which are too hard to drill out.