Topic: Head light door screws

[ruppstang]

The assembly manual calls for a 55947-S45 oval head SS screw for attaching the head light doors. That is what comes with the NOS fender extensions that I have purchased in the past. I often find a flat headed screw used on what I believe to be very original cars. Were possibly one or more of the assembly plants using a different screw?
Marty

[67gtasanjose]

The assembly manual calls for a 55947-S45 oval head SS screw for attaching the head light doors. That is what comes with the NOS fender extensions that I have purchased in the past. I often find a flat headed screw used on what I believe to be very original cars. Were possibly one or more of the assembly plants using a different screw?
Marty

+1

Not sure why the manual would suggest that. Is it possible the manual got it wrong or you mistook the image for the three holding the headlamp bulb retainer? (I have the Body assembly manual out for my 67, I didn't see a page for the headlights in it)

[jwc66k]

Not sure why the manual would suggest that. Is it possible the manual got it wrong or you mistook the image for the three holding the headlamp bulb retainer? (I have the Body assembly manual out for my 67, I didn't see a page for the headlights in it)

Try the 68 electrical manual, AM0023 page 7. 1967 Mustangs (AM0018 page 7) use an identical screw with a different part number, 374798-S.
Difference in factory uses may be attributed to line shortages. I can't see an assembly line stopped for a "screw".
Jim
 

[196667Bob]

Assuming we are talking about the Headlight Door, 13064, let me "muddy up" the waters (once again). The 1960-68 MPC Illustrations page (dated April 1967) calls for this screw to be  # 374798-S, which is a No. 8-18 Oval Head SST Phillips Trim screw, 1.00" long. The corresponding Text page (dated February of 1968) calls for # 378852-S, which is a No. 10 x 1.00", Self Tapping Fillister Head, Plain Phillips Screw (this is also what is shown in the 1965-72 MPC dated May of 1975).

Thus, at least to me, this says that sometime between April of 1967 and February of 1968, the Oval Head Trim Screw was replaced by the Fillister Head Screw. Now, to "muddy things up" a bit, while the 1967 and 1968 electrical Assembly Manuals (dated 7/66 and 11/67 respectively) show Part #'s whose descriptions are identical (#8-18 Oval Trim Head Phillips SST), the illustrations in both Manuals depict a Fillister Head Screw. So, based on the above, it appears that they started out with an Oval Trim Head SST Screw, changed to a Fillister Head Plain Screw, and then went back to the Oval Trim Head SST Screw.

As an aside, and adding to the "mud", the 1966 Electrical Assembly Manual, dated 03/30/66, shows that for the Headlight Doors (which are of course considerably different), the screw used is the 378852-S, the No. 10 Fillister Head, Plain, Phillips Screw. This is just meant to show that this screw was available prior to the February 1968 MPC Text.

Bob

[WT8095]

Marty, are you asking specifically about 67 or 68, or in general about both years? You didn't say in your original post.

[jwc66k]

Assuming we are talking about the Headlight Door, 13064, let me "muddy up" the waters (once again). The 1960-68 MPC Illustrations page (dated April 1967) calls for this screw to be  # 374798-S, which is a No. 8-18 Oval Head SST Phillips Trim screw, 1.00" long. The corresponding Text page (dated February of 1968) calls for # 378852-S, which is a No. 10 x 1.00", Self Tapping Fillister Head, Plain Phillips Screw (this is also what is shown in the 1965-72 MPC dated May of 1975).

Thus, at least to me, this says that sometime between April of 1967 and February of 1968, the Oval Head Trim Screw was replaced by the Fillister Head Screw. Now, to "muddy things up" a bit, while the 1967 and 1968 electrical Assembly Manuals (dated 7/66 and 11/67 respectively) show Part #'s whose descriptions are identical (#8-18 Oval Trim Head Phillips SST), the illustrations in both Manuals depict a Fillister Head Screw. So, based on the above, it appears that they started out with an Oval Trim Head SST Screw, changed to a Fillister Head Plain Screw, and then went back to the Oval Trim Head SST Screw.

As an aside, and adding to the "mud", the 1966 Electrical Assembly Manual, dated 03/30/66, shows that for the Headlight Doors (which are of course considerably different), the screw used is the 378852-S, the No. 10 Fillister Head, Plain, Phillips Screw. This is just meant to show that this screw was available prior to the February 1968 MPC Text.

Bob

You cannot use the "MPC" to determine the hardware used on the assembly lines. At best, the documentation "may" confirm what was used.
The two identical screws with different part numbers, 55974-S and 374798-S, are the result of the Ford Motor engineering practice of listing the approved source on the drawing. A single document defines the dimensions, material, tolerance and source - easy for buying, receiving and incoming inspection. This practice locks you into a single source for that part. It was a common practice. Another source requires a new drawing and a new part number.
The differences between the illustration and the part number section having differences is most likely attributed to human error or a lack of knowledge of the product. Ford was selling cars, service was secondary, documentation was an after thought, concourse grade cars were not considered.
Jim     

[midlife]

Assuming we are talking about the Headlight Door, 13064, let me "muddy up" the waters (once again). The 1960-68 MPC Illustrations page (dated April 1967) calls for this screw to be  # 374798-S, which is a No. 8-18 Oval Head SST Phillips Trim screw, 1.00" long. The corresponding Text page (dated February of 1968) calls for # 378852-S, which is a No. 10 x 1.00", Self Tapping Fillister Head, Plain Phillips Screw (this is also what is shown in the 1965-72 MPC dated May of 1975).

Thus, at least to me, this says that sometime between April of 1967 and February of 1968, the Oval Head Trim Screw was replaced by the Fillister Head Screw. Now, to "muddy things up" a bit, while the 1967 and 1968 electrical Assembly Manuals (dated 7/66 and 11/67 respectively) show Part #'s whose descriptions are identical (#8-18 Oval Trim Head Phillips SST), the illustrations in both Manuals depict a Fillister Head Screw. So, based on the above, it appears that they started out with an Oval Trim Head SST Screw, changed to a Fillister Head Plain Screw, and then went back to the Oval Trim Head SST Screw.

As an aside, and adding to the "mud", the 1966 Electrical Assembly Manual, dated 03/30/66, shows that for the Headlight Doors (which are of course considerably different), the screw used is the 378852-S, the No. 10 Fillister Head, Plain, Phillips Screw. This is just meant to show that this screw was available prior to the February 1968 MPC Text.

Bob

Aside from the previous comments, doesn't it seem strange that there was a change from a #8 to a #10 screw as well?

[ruppstang]

Here is the head light door with the factory flat headed screw. The car pictured is a 68 SJ coupe built 7-16-68. I also have a 67 SJ GTA convertible built 11-04-66 it also has the same screws. These are tough to find unless it is in a parts car.
Marty

[196667Bob]

You cannot use the "MPC" to determine the hardware used on the assembly lines. At best, the documentation "may" confirm what was used.
The two identical screws with different part numbers, 55974-S and 374798-S, are the result of the Ford Motor engineering practice of listing the approved source on the drawing. A single document defines the dimensions, material, tolerance and source - easy for buying, receiving and incoming inspection. This practice locks you into a single source for that part. It was a common practice. Another source requires a new drawing and a new part number.
The differences between the illustration and the part number section having differences is most likely attributed to human error or a lack of knowledge of the product. Ford was selling cars, service was secondary, documentation was an after thought, concourse grade cars were not considered.
Jim     

Jim : Just as a follow up; the 1967 Electrical Assembly Manual shows this screw as 374798-S; the 1968 Electrical Assembly Manual shows it as 55947-S45 (not 55974). The   55947-S45 shows in one of my Standard and Utility Parts Catalogs as a # 8-18, Oval Head SST Self Tapping Screw. I cannot find the 374798-S screw in any of the 9 S&UP Catalogs that I have. However, it does show up in AMK's Fastener Guide with the identical description as the 55947-S45.

Aside from the previous comments, doesn't it seem strange that there was a change from a #8 to a #10 screw as well?

+1

Here is the head light door with the factory flat headed screw. The car pictured is a 68 SJ coupe built 7-16-68. I also have a 67 SJ GTA convertible built 11-04-66 it also has the same screws. These are tough to find unless it is in a parts car.
Marty

Marty : I assume (?) that those are self tapping screws as well ? What is the thread ? The length ? Are they SST, Chrome Plated, or ?

Bob

[67gtasanjose]

Yes, now I see what the ELECTRICAL '67 assembly manual shows (AM0018 page 7) , I did not compare to what AMK offers but I can add that the picture Marty provided of the red car looks correct, compared to my original example.

They look like #8, stainless steel, sheet metal screws with a blunt tip (not your typical pointed tip sheet metal screw) and are countersunk (to fit the countersunk taper of the headlight door), so they are a tapered, small phillips drive head. They are approximately 7/8"inch in overall length.

[196667Bob]

Richard : Thanks ! I don't care what the Assembly Manuals note, to me the Flat head looks much better than either the Oval Head or Fillister Head. And as you and Marty noted, this appears to be what you have seen. I can't remember if mine are like that or not, as it's been a couple of years since I removed them. I'm anxious to check them in a few weeks.
Just for info, NPD, CJ and MU all appear to have the Screw Kits, with new plastic "nuts". All are Flat Head (no size or length given of course), but only NPD notes they are SST. Also, from the picture, it appears they are pointed Sheet Metal Screws.
I can get correct blunt tip, plastic cutting screws  In SST or Zinc Plated. However, in SST, maximum length I can get is 3/4". Does it appear that the 3/4" would still work OK ?

Thanks again,

Bob

[67gtasanjose]

I can get correct blunt tip, plastic cutting screws  In SST or Zinc Plated. However, in SST, maximum length I can get is 3/4". Does it appear that the 3/4" would still work OK ?

Thanks again,

Bob

I would think so, keep in mind my measurement was 7/8" OVERALL LENGTH.

[WT8095]

Here's some info from Ford ca 1991 that will hopefully clear up the descriptions. There are a few differences between "Oval Head" and "Oval Trim Head" screws:

• Oval Trim heads have smaller diameter heads relative to the nominal thread. An 8-18 has a head sized like a normal #6 screw.
• Oval trim head screws have a larger crown radius, i.e. they're "flatter", but not quite flat.

The differences may explain some of the apparent size conflicts in the various Ford documents that have been cited. However, the screws in the photos really do look like flat trim head screws to me, and that's what I seem to recall seeing on the various 67-68's that I've parted out. (I'm not near my '68 to check either) The fastener documentation I have does not cover flat trim head screws, but I'll keep looking...

[Laurie S.]

My original owner Dearborn-built 1968 coupe has the oval head screws.

[67gtasanjose]

My original owner Dearborn-built 1968 coupe has the oval head screws.

Great, another small "detail" that we can watch out for

We might wish to now include build data if we continue to find original examples that differ.

I know without a doubt, the ones I showed earlier were original to my build date and assembly plant. No repaint before I bought it and I made an effort to NOT paint them at repaint, being absolutely sure to put the right ones back in. (but obviously I LOST one along the way, see reply dated 4/22/16)