The Phillips screw was developed in the 1930’s. The Pozidrive drive screw was an evolution of the Phillips system released by GKN in late 1962 to eliminate the tendency of the Phillips to drive out the tool axially. The E-Type pre-dates the Pozidrive so did not use them.
Easy to spot the difference as the Posidrive has four star lines etched into the head. The recess of the Phillips is conical (hence the tool driving out axially) whereas thePozidrive has parallel flanks.
So given Jaguar were not going to change inventory and tooling willingly they saw no advantage of switching to Pozidrive so Phillips was used throughout E-Type production. No star lines means Phillips and I have never seen any OEM screws with star lines. ‘DAZ’ is just a code prefix not a manufacturer. In the UK DAZ was a very well known brand of clothes detergent marketed from the 1950’s onwards.
If Jaguar changed from Phillips to Pozidrive they would have had to retool the Factory and the Service Departments. The screwdriver in the toolkit would need to be changed and the whole supply and spares chain would be disrupted at huge costs for zero gain. Can you imagine the chaos in the service centres around the world as they tried to order the correct screws and there would inevitably bonnets with a mixture of both types. The drivers are not interchangeable, use the wrong one and you risk damaging the tool, screw or paintwork. Mr Arthur Whittaker, Jaguar Chief Buyer, was not renown for spending money on anything and was more concerned about reducing costs to keep sir William happy.
In support of what David is positing, I have looked at my SPC J.37 published Nov 1965 (4.2 Etype) and SPC J.38 published Jan. 1967 (Etype 2+2). Both, under the section for Bonnets and Front Wing Assy, list the DAZ.814/10C part number for all the self tapping screws listed. They also all show spring washers. I don’t have any Series 2 or Series 3 catalogs. Maybe someone that does can see if the part numbers changed.
I also have a collection of the subject screws that have been removed either from my 1963 FHC or my 1967 2+2. Per my close inspection and as you can see from this picture, none have the hash marks that distinguish a Posi-Drive screw. These screws have been bead blasted and zinc plated. I also purchase a product from McMaster, Phillips Rounded Headed Sheet Metal Screws, 18-8 stainless, Size 14, 5/8" long that to my eyes are the same as my original DAZ screws.
The 3.8 parts manual lists BD.16939/2 self tapping screws throughout in the bonnet assembly. Under each of these screws it lists a FG.104/X spring washer. It does not show DAZ.814/10C anywhere that I can find, including the stone guard mounting. But the 4.2, SII and SIII manuals show the DAZ.814/10C. It appears that Jaguar introduced pozidriv on the 4.2 and continued on.
In which case providing an example with the standard Pozidrive markings on the head should be a doddle!
There is nothing in either the SB’s or SPB’s detailing the change and the need for new tools. My guess is the change in part number has nothing to do with Pozidrive, just a change in screw specification for that application.
David is absolutely correct.
In this case (SELF-TAPPING (SHEET METAL) SCREWS)
D a b . c d e / f g BASIC PART NUMBER FOR SELF-TAPPING SCREWS
D a ? . ? ? ? / ? ? a = A – POINTED TIP - SHEET METAL SCREW - COARSE THREAD
‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’= J – BLUNT OR FLAT TIP FOR SPIRE NUTS
‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’''Z – POINTED TIP - SHEET METAL SCREW - FINE THREAD
…Not sure of the difference between A and Z designations
D ? b . ? ? ? / ? ? b = B – BLACK PAINT FINISH (GLOSS)
‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘C – CHROME
‘’’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘‘N – NICKEL
‘’’’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘‘J – BLACK PAINT FINISH (SATIN)
‘’’’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’‘’''Z – ZINC (CLEAR)
The above is to be found on the top of page 4 (of 14). The other designations of the fastener refer to length of shaft, fine/coarse, etc.
I have attached what I believe to be a complete “decoding sheet” for Jaguar hardware (found somewhere, sometime by someone on the 'net).
Richard, you are correct that the original SPC published in 1961 lists the self tappers under a Jaguar part number, BD.16939/2. I’m just not following your logic that the DAZ product was Pozidriv. As I have posted above, I have screws from 1963 and 1967 cars and they are clearly not marked as Pozidriv. See post 23.
Also, it is apples to oranges but Haddock/Mueller has just one entry in the Index for Pozidriv. It takes you to a photo on page 47, where it states for photo 6 “These headlight retaining ring screws have the small slash marks in between the troughs of the recess for the screwdriver. These appear to be Pozidriv identification marks. The Authors have never seen evidence of Series 1 E-Type being delivered from the factory with Pozidriv screws retaining the headlight rings and suspect these are non-factory replacement screws.” They are talking about headlights but I would assume if the bonnet screws were changed to Pozidriv, they would have mentioned it. They are nothing if not thorough.
Regardless, the original question was about spring washers, which I believe has been put to bed. Unless one is a total purist, most of us will probably be very happy with the screws provided in our bonnets, be they Phillips or otherwise.
And Craig, thanks for that. I am glad the screws were not the product of a laundry detergent mfg
I’ll add that my ‘66 OTS has never shown any evidence of Pozi-drive screws and I tore very original rust bucket down completely. I am well aware of what a PD looks like as they were used extensively on my 2 XJ 40s.
There have been discussions here before on the use of Pozidriv screws on the Series 2, and some of the evidence seems quite convincing, at least for some applications. This thread springs to mind:
Everyone who checked their car found #4 Pozidriv heads on the screws for in the USA/Canada secondary inlet manifold blanking cap. This is despite the Jaguar Parts List indicating part # UCS.831/7H which the fastener decoder in common usage here translates as having a Phillips Round Head. I would hazard a guess that these particular fasteners are rarely if ever removed, so it seems very unlikely that they have been substituted during the life of all the identified cars. This leads me to two conclusions:
Stating that no Pozidriv fastener was ever used on an E-Type seems to go against a significant weight of evidence to the contrary.
Since the fastener decoder we use here does not include a code for Pozidriv heads it seems likely that Jaguar did not differentiate between Phillips and Pozidriv at that time.
Note: I’m not suggesting that this says anything about the Bonnet Self-Tapping screws, which were the original subject of this thread. As @Heuer has indicated, if such screws were Pozidriv at some point, someone here should be able to find them on their “original” bonnet.
Isn’t it pretty well documented that posidrive screws were used at the rear of the seat tracks to bolt them to the car’s floor? At least so on a Series II?
This is only circumstantial but I was working as a student engineer at Triumph in the early 70s - sister company to Jaguar within the BL organisation, close geographically and organisationally. That training included a couple of months in the Fasteners Lab and I don’t recall encountering the Pozi word there, in fact my first memory is mid-70s when I moved to a company which contracted its fastener supply out to a local specialist. I imagine their presence on some bought-in parts, such as lamps, could be simply that the supplier had changed to Pozi?
I’d have paid more attention if they’d told me I’d find this fascinating fifty years later…
Growing up in the UK in sixties we only had two types of screws - slotted and cross-head. Nobody ever referred to the latter as Phillips or Pozidrive and for years we all used the same cross-head screwdrivers in whatever came out of the box or fitting. In fact Phillips became the generic term for all cross-heads and I don’t recall even being able to buy a Pozidrive driver (had I known they existed!). Safe to assume Jaguar employees were the same and just ordered ‘cross-heads’ for the production line.
