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Wanted: Pozi oval-head R/CSK screw


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#1 CDCJ

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Posted 19 February 2012 - 15:07

Hi all,

Now I'm looking for the screw for the restoration as original.

*Pozi Oval head(same as R/CSK) Fully Threaded Screw
#10-32(UNF)  length: 5/8(low priority)
The head must have Pozi Oval head(same as R/CSK) and diameter must have 7.7mm.
I attached the pictures.

Posted Image
Posted Image

But it's very hard to find correct one. (I've got one before. But it too big head!)
I need your help.
Please advice me about screw dealer or company for custom-made screw.

I very much appreciate your cooperation.

Best regards,
Hiro :)

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#2 Bloggsworth

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Posted 19 February 2012 - 15:32

Are you in Australia or Alaska, it would help to know...

#3 D-Type

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Posted 19 February 2012 - 15:37

Be fair! Hiro's profile says he is in Japan. What more can we ask for?

#4 Garsted

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Posted 19 February 2012 - 16:14

Hello Hiro,
I know this is not exactly what you are looking for. bit its close. You could maybe ask them if they can get exactly what you want. I have used this company myself and they were very good.

http://www.a2stainle..._AF2M.aspx?nh=1

Regards,
Steve

#5 Charles E Taylor

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Posted 19 February 2012 - 16:57

Please check the angle for the countersink.

I think these are what you are looking for.

NAS 387

Drawing Here


This company will send small quantities anywhere.




I hope this helps.



Charlie

#6 TEDD

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Posted 19 February 2012 - 19:00

10-32 x 5/8 Phillips Oval Head Machine Screw

www.mcmastercarr.com or at www.fastenal.com


#7 CDCJ

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Posted 20 February 2012 - 13:51

Many thanks for the information.
However it's always the Head Diameter bigger than original.
So I think it's very difficult find same screws as original.
Head Diameter: I need 7.7mm(0.30 inch)
Do you know a company for custom-made screw?
Kind regards,
Hiro :)

#8 cheapracer

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Posted 20 February 2012 - 13:58

However it's always the Head Diameter bigger than original.


Any half-wit on a lathe can turn them down.


#9 Sharman

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Posted 20 February 2012 - 14:22

Any half-wit on a lathe can turn them down.


My initial thought but it won't work because the proportions will differ, or there will be a flat on the head. Useful for getting a grip with a pair of pliers but I don't think he has that in mind.

#10 D-Type

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Posted 20 February 2012 - 15:11

Any half-wit on a lathe can turn them down.



My initial thought but it won't work because the proportions will differ, or there will be a flat on the head. Useful for getting a grip with a pair of pliers but I don't think he has that in mind.

Would it work if you turned down the countersink face until the head was the right diameter?

Or am I talking a load of the proverbial spherical rhomboids?

#11 Tony Matthews

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Posted 20 February 2012 - 16:08

Would it work if you turned down the countersink face until the head was the right diameter?

Or am I talking a load of the proverbial spherical rhomboids?

Just turn the countersink down a bit, so you speak with great wisdom, D-Type...

Edited to add that I've always known them to be 'raised countersunk' heads. Nothing oval about them, unless thhey've been in a vice.

Edited by Tony Matthews, 20 February 2012 - 16:10.


#12 Allan Lupton

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Posted 20 February 2012 - 17:25

Just turn the countersink down a bit, so you speak with great wisdom, D-Type...

Edited to add that I've always known them to be 'raised countersunk' heads. Nothing oval about them, unless thhey've been in a vice.

As they seem to be setscrews rather than bolts there's nothing but thread to hold them by in the lathe, so not as easy as all that to turn down the head/change the countersink angle.
I agree about oval - I think it must be US-usage as it seems to be understood by most of the posters on here.

#13 Tony Matthews

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Posted 20 February 2012 - 18:06

As they seem to be setscrews rather than bolts there's nothing but thread to hold them by in the lathe, so not as easy as all that to turn down the head/change the countersink angle.

Where there's a will there's a way! Two pairs of lock-nuts? (I haven't checked the aspect ratio). Clearance-fit tube and Loctite? I don't think you would have to tighten the chuck sufficiently to damage the thread, for it to be tight enough to gently skim the countersink.  ;)

#14 Bloggsworth

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Posted 20 February 2012 - 23:38

Just turn the countersink down a bit, so you speak with great wisdom, D-Type...

Edited to add that I've always known them to be 'raised countersunk' heads. Nothing oval about them, unless thhey've been in a vice.


The side profile of the head is a section of an oval, not of a hemisphere.

#15 elansprint72

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Posted 21 February 2012 - 09:12

Hiro- does this relate to your steering-wheel enquiries on the Elan site? Small world!

Looking at the side view of the two screws it looks like the one on the left has had some work done on it- notice the flattened last turn of thread. The diameter of the head needs to be reduced by approximately 1mm (standard size is 11/32" for this screw, which is 8.73mm).
The best option would be to mount the screw in a collet in a lathe (only a blacksmith would use a chuck ;) ) turn the taper and then file the radius back to size.
The problem will be that Pozidrive screw heads usually have some crude hardening to the area of the slots (I'm not familiar with the exact process). Strangely my screw-thread bible Caroll Smith's "Nuts, Bolts, Fasteners and Plumbing Handbook" does not even mention Phillip's or Pozidrive, however he does confirm that a US-speak oval head screw is referred by us Brits as a raised countersunk.


Once I was a tool-maker. :well:

Edited by elansprint72, 21 February 2012 - 09:17.


#16 CDCJ

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Posted 24 February 2012 - 12:32

Hi Pete and all,
Thank you for the information. It was very beneficial.
Yes! The screws for period steering wheel of Lotus racing cars.
Finally I decided to correct the screw like original.
Regarding Pozidrive or Phillips, Normally, Pozidrive has been used in Britain and Phillips has been used in the United States?
Please tell me. We have never used Pozidrive here in Japan.
Thank you.
Hiro :)

#17 Tony Matthews

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Posted 24 February 2012 - 14:28

Phillips was introduced first, then Pozidrive, and since then other variations. Both Phillips and Pozidrive are used, so you need a full set of both drivers in the UK!

#18 RogerFrench

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Posted 24 February 2012 - 18:17

Phillips was introduced first, then Pozidrive, and since then other variations. Both Phillips and Pozidrive are used, so you need a full set of both drivers in the UK!


Anorak time - isn't it actually "Posidriv"?


#19 monoposto

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Posted 24 February 2012 - 19:29

Anorak time - isn't it actually "Posidriv"?



Pozidriv®, actually

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#20 CDCJ

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Posted 25 February 2012 - 14:43

What's different between Phillips and Pozidriv®?
Of course I understand the different "+" pattern.
Why did Pozidriv® appear?
Please tell me a merit and a demerit of Phillips and Pozidriv®.
Thank you.
Hiro :)

#21 D-Type

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Posted 25 February 2012 - 18:34

Here they say the Pozidrive doesn't "cam out" as readily as a Phillips head. This Wikipedia entry describes some of the differences.

If the screws are on a Lotus, they will have been readily available commercially at the time - Chapman wouldn't have commissioned anything specially. He'd have sized the countersink to fit a stock screw.

#22 Tony Matthews

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Posted 25 February 2012 - 20:29

I've just had a look at the photo in the OP, and the screw on the left is Phillips, the one on the right is Pozi! I don't think Pozi is correct - Phillips is the earlier type.

#23 monoposto

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Posted 25 February 2012 - 22:31

Hiro,

This is a possibility . . .

http://jp.rs-online.com/web/p/fastener-kits/2508788225/

This is meant to be used in conjunction with a cup washer, so maybe the outside diameter of this screw is less than that of the conventionally available screw ?
Various lengths are available, without the cup washer.

I cannot see a dimensioned drawing on the Hammond website to check however.

http://www.hammondmfg.com/hardware.htm

Also be aware there are two common angles for countersinks : 82 deg. is mostly used on commercial screws, and 100 deg. for aerospace applications.



#24 Catalina Park

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Posted 26 February 2012 - 03:34

Most mass production automotive screws are "pozi" They are used because they hold on to the tool for easier installation.

#25 TEDD

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Posted 26 February 2012 - 06:03

found some here on page 7 http://www.srfast.co...alfasteners.pdf

10-32 x 1 chrome plated phillips oval head machine screw with a #8 size head (.312)


box of 20 here

http://shop.northlan...-x-1-N01413.htm

#26 plannerpower

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Posted 26 February 2012 - 07:08

The statement in Wikipedia and elsewhere that the Phillips head was designed to "cam-out" and so limit torque on the fastener seems to have little foundation.

Phillips was granted several patents for his screw-head and for the matching driver; there is no mention that I can find of the benefits of "camming-out".

Relevant extracts;

Posted Image

Posted Image



#27 CDCJ

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Posted 26 February 2012 - 12:14

Hi Tedd and all,
Thank you very much for the information.
I will ask the seller. However it must be Phillips only.
(It's does not matter to me.)
However I always have seen Pozidriv® in 60's British cars.
If the Pozidriv® doesn't "cam out", it's better use for car than Phillips?
Did both Phillips and Pozidriv® exist in 60s?
Kind regards,
Hiro :)

#28 elansprint72

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Posted 26 February 2012 - 16:27

The Phillips screwdrivers have a different point from the Pozidriv, I'll post a link later to illustrate my point!

EDIT:

Item from Austin Healey Club mag.

This gives the story of the two types and illustrated the differences.

Edited by elansprint72, 26 February 2012 - 16:39.


#29 RTH

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Posted 26 February 2012 - 16:46

I well remember having both phillips and pozi screwdrivers in the mid 1960s certainly date back that far.
Pozi were far better than phillips when used with power wrenches on assembly lines. The Pozi could actually be placed on the end of the tool and stay there. The greater surface area provided greater torque for installation and removal less slip out a superior solution all round.

#30 RJE

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Posted 27 February 2012 - 08:27

Sorry to throw a spanner (or for that matter a screwdriver) in the works, but could it not be possible that the required screws are BA. A 2BA screw diameter measures .185" against .190" of the 10-32 UNF, the TPI is 31.86 against 32 and the listed screw head diameter is .319", only .016" or so larger than the 7.7mm listed in the post. All of the measurments are near enough for them to be easily mistaken particually when looking at an old screw and a 32 TPI thread gauge will fit either size. BA was extensively used during the 1960s and was then readily available. I seem to remember that you could get a domed cross head counter sunk screw.

With regard to machining down the screw heads. Surely if the items are to be used as a steering wheel attachment where by very definition they are in a state of shear, this must be a non starter.

#31 plannerpower

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Posted 27 February 2012 - 08:47

BA threads have a 47.5 degree angle; that's sufficiently-far from 55 or 60 to make them distinguishable with a good thread gauge (and not be interchangeable with 55 or 60 unless very poorly made).

2BA is common; it's used in darts.

#32 Tony Matthews

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Posted 27 February 2012 - 08:52

With regard to machining down the screw heads. Surely if the items are to be used as a steering wheel attachment where by very definition they are in a state of shear, this must be a non starter.

And much easier to re-countersink the holes. That's probably sacriligeous though...

#33 RJE

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Posted 27 February 2012 - 11:38

BA threads have a 47.5 degree angle; that's sufficiently-far from 55 or 60 to make them distinguishable with a good thread gauge (and not be interchangeable with 55 or 60 unless very poorly made).

2BA is common; it's used in darts.


I agree but if you were not familiar with the differences between UNF and BA threads an assumption that the thread was UNF particually in Japan where US thread patterns are more common it would be an easy mistake to make.

#34 RJE

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Posted 27 February 2012 - 11:50

BA threads have a 47.5 degree angle; that's sufficiently-far from 55 or 60 to make them distinguishable with a good thread gauge (and not be interchangeable with 55 or 60 unless very poorly made).

2BA is common; it's used in darts.



Further to what I have just posted: The photographs seem to show a rounded top to the thread which is typical of BA thread forms while generally US threads have a flat top. However I will accept that this is all a bit arbitrary.

#35 CDCJ

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Posted 28 February 2012 - 15:31

Hi RJE and all,
Many thanks for the information.
I paid my attention only to the screw of an inch(UNF) or a millimeter.
Now I understand other standards "British Association" screws.
It's British standard. So it's suite for British classic cars in 60's!
The 2BA screw head diameter seems to .319", It's will be smaller than the standard #10-32(UNF) screws.
Can I have the specification(include head diameter) of British Association screws?
The "British Association" screws used for British classic cars at that time?
also "British Association" screws have both Phillips and Pozidriv type?
Can I recognize the difference between Phillips and Pozidriv easily?
I think the Phillips has just four simple slots cut out like the first photos (left).
and Pozidriv has four simple slots cut out with mark like the first photos (right).
Is this correct? Please tell me.
Kind regards,
Hiro :)

#36 Tony Matthews

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Posted 28 February 2012 - 16:38

I think the Phillips has just four simple slots cut out like the first photos (left).
and Pozidriv has four simple slots cut out with mark like the first photos (right).
Is this correct? Please tell me.

Correct. If you look closely you will see that the four small lines each point to small suplementary grooves going down to the point.

Edited by Tony Matthews, 28 February 2012 - 16:41.


#37 carlt

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Posted 28 February 2012 - 16:48

Hi RJE and all,
Many thanks for the information.
I paid my attention only to the screw of an inch(UNF) or a millimeter.
Now I understand other standards "British Association" screws.
It's British standard. So it's suite for British classic cars in 60's!
The 2BA screw head diameter seems to .319", It's will be smaller than the standard #10-32(UNF) screws.
Can I have the specification(include head diameter) of British Association screws?
The "British Association" screws used for British classic cars at that time?

Hiro :)


I remember having troubles with British Classic Car steering wheel boss' [ sourcing new machine screws for missing ones , or more commonly replacing ruined/crossed threads ]
also once on an aftermarket smaller steering wheel on a Lotus 7
They were eventually found to be BA thread [ also the same style head that you show]


#38 RJE

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Posted 28 February 2012 - 19:32

Hi RJE and all,
Many thanks for the information.
I paid my attention only to the screw of an inch(UNF) or a millimeter.
Now I understand other standards "British Association" screws.
It's British standard. So it's suite for British classic cars in 60's!
The 2BA screw head diameter seems to .319", It's will be smaller than the standard #10-32(UNF) screws.
Can I have the specification(include head diameter) of British Association screws?
The "British Association" screws used for British classic cars at that time?
also "British Association" screws have both Phillips and Pozidriv type?
Can I recognize the difference between Phillips and Pozidriv easily?
I think the Phillips has just four simple slots cut out like the first photos (left).
and Pozidriv has four simple slots cut out with mark like the first photos (right).
Is this correct? Please tell me.
Kind regards,
Hiro :)


Hiro
Try looking at www.britishfasteners.com and click on BA it may answer a lot of your questions. You are right about the Phillips and Pozidriv heads, the Pozidriv is the one on the right of your picture. BA screws were made with both types although now they seem to be mainly the pozidriv pattern. I think what you are looking for are still available but if you cannot find them I will try to find a supplier for you.

#39 CDCJ

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Posted 29 February 2012 - 16:37

Hi RJE and all,
Thank you very much indeed for the information.
The world of a screw is very deep.
Now I got a lot of information and will take the correct screws for restoration.
Kindest regards,
Hiro :)


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#40 carlt

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Posted 29 February 2012 - 21:34

It's a short thread

#41 Tony Matthews

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Posted 01 March 2012 - 00:33

Pozitively. Another point is that, regardless of driver-type, they all hurt when you kneel on them.

#42 GMACKIE

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Posted 01 March 2012 - 02:56

It's a short thread

Yes......but getting longer. My 2c worth, 2BA.


#43 carlt

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Posted 01 March 2012 - 09:13

A fine example of the correctly pitched thread

#44 Tony Matthews

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Posted 01 March 2012 - 09:24

You deserve an Honorary BA...

#45 GMACKIE

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Posted 01 March 2012 - 09:28

I look like ending up with BA, as well. :rolleyes:

#46 RJE

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Posted 02 March 2012 - 07:16

The last few threads are B****y Awful.

#47 elansprint72

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Posted 02 March 2012 - 07:47

This thread is the very acme of threads, it is the crest, takes the lead and has superb pitch, getting to the root of the subject. It has unified coarse, fine, extra fine and special members of the forum and will be a buttress against the assaults of the Panzergewinde.


I'll get me Fahrradgewinde, before you think I'm (self) tapped.

#48 GMACKIE

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Posted 02 March 2012 - 08:24

If this doesn't stop soon, I think I might die.

#49 carlt

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Posted 02 March 2012 - 09:14

what's all this Wit worth ?
even if it's not fine.
sometimes course is better,
without it , it's all just BS,BS !

Edited by carlt, 02 March 2012 - 09:22.


#50 Sharman

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Posted 02 March 2012 - 09:21

This thread is the very acme of threads, it is the crest, takes the lead and has superb pitch, getting to the root of the subject. It has unified coarse, fine, extra fine and special members of the forum and will be a buttress against the assaults of the Panzergewinde.


I'll get me Fahrradgewinde, before you think I'm (self) tapped.

Being extra coarse all I can say is "Screw You"