#5-40 machine screw for 53-55 side curtain?

[Eric F.]

I'm restoring the side curtains for an early 54. The 4 screws that hold the T-bracket on the interior of the windows are #5-40 x 1/2" (Yes, #5-40 not #4-40). They appear original and they move in and out easily so I believe they are original. One is slightly bent so I want to replace it but this is the first time I have encountered #5-40 threads on a machine screw for this car; to me it's very unusual. Everything about the window, bracket and its installation appears original and untouched.

Has anyone else encountered these threads on the screws for this bracket?

[Larry M.]

Re: #5-40 machine screw for 53-55 side curtain?

They are available from places like McMaster-Carr if needed. There may also be many other sources/suppliers if you search.

Larry

[Eric F.]

Re: #5-40 machine screw for 53-55 side curtain?

I can find the screws but I want to get confirmation they are supposed to be #5-40 threads.

[David B.]

Re: #5-40 machine screw for 53-55 side curtain?

If you can provide a part #, it should be relatively easy to answer your question.

[Edward B.]

Re: #5-40 machine screw for 53-55 side curtain?

Considering the diameter of a #5 it shouldn't take too much to straighten the screw.

[Wayne L.]

Re: #5-40 machine screw for 53-55 side curtain?

Eric-
Yes, #5-40 machine screws are correct.
Wayne

[Dan D.]

Re: #5-40 machine screw for 53-55 side curtain?

Eric,

I just took a look at my 54 side curtains. I believe your assessment of 5-40 is correct. I believe my curtains to be correct, as I have owned the car since 1961. My car has the gull wing locks on the vent windows, which I believe to be a dealer installed option and not standard for a March 54 built car. Other than that, I don't believe my windows have ever been touched. The driver side plexiglass is dated 2-54; the right side is 3-54.

I pulled a couple of the screws in question and compared them to 4-40 and 6-32 screws. A 4-40 screw measures .108 in diameter, 6-32 is .135, and the side curtain screws measure .121. A 4-40 screw will easily screw in but is loose. This indicates that the thread is 40, but the screw is too small. Likewise a 6-32 is too large. So I believe 5-40 is correct.

The lower screws are 3/8 long; the vertical ones are 1/2" long. They are chrome plated filister(sp) head screws.

I have attached a couple of pictures. Hope this helps.

-Dan-



These are the screws from the side curtain, and 4-40 and 6-32.

[Eric F.]

Re: #5-40 machine screw for 53-55 side curtain?

Wayne, Thanks for the affirmation.

Dan, Thanks for taking the time to explain in detail and include photos. Our cars are similar in that they both have the gull wing locks. This car is an early 54 and I've found numerous items that are referenced to be 53 or late 53 to early 54. The side curtains are dated 11-53 and 12-53. This car was built in May 54.

I've included photos of one of the side windows that show the top two screws on the vertical part are chrome oval head phillips and the bottom two on the horizontal part are cad plated pan head slotted; both styles are #5-40 x 1/2. The different screw types are in the same locations on both side curtains. The judging manual states 53 had pan head slotted and 54-55 had oval head phillips. Since they're in the same locations on both sides I suspect they were from the factory. Maybe they made during the transition from slotted pan head to phillips oval head.

For what it's worth; I have a source for the #5-40 pan head slotted screws but can't seem to find them in the oval head phillips. That's murphys law though because the bent screw has a phillips head.
I wouldn't take a chance straightening it because it could compromise the integrity and cause it to break while installing it now or in the future. I would not want to try and remove a broken #5-40 size screw from anything; especially a 62 year old chrome and Plexiglas side curtain.

Thanks to each of you for your contributions.

[Larry M.]

Re: #5-40 machine screw for 53-55 side curtain?

Found several sources for oval head slotted screws in 5-40, but so far have not located the phillips oval head in that size.

Larry

[Eric F.]

Re: #5-40 machine screw for 53-55 side curtain?

Found several sources for oval head slotted screws in 5-40, but so far have not located the phillips oval head in that size.

Larry

Larry,

I ran into the same problem. I checked sources on the internet and beyond. I even have some folks in the industry trying to find some. I'll post something here if I ever find any. Thanks for doing the research.

Eric

[Dan D.]

Re: #5-40 machine screw for 53-55 side curtain?

Eric, I don't know how bad your screw is bent, but if not too bad you should be able to straighten without compromising the strength. And they don't have to be very tight. But it would take a couple of nuts to do it so you don't damage the threads.

Have you tried to locate a 5-40 die? That may be impossible too, but if so you could cut down and re-tap a larger screw.

Your bag is in much better shape than mine is.

I believe you have an early 54, based on the slotted head screws and early date code of the plexiglass. But if so, then you car had to be built before May 54. That would be a late build car. Production started in January of 54. Production started later than normal as they moved the assembly plant from Flint to St. Louis.

-Dan-

[Gary H.]

Re: #5-40 machine screw for 53-55 side curtain?

Check with Steve Newsom!