Screw Number vs. Screw Specs

[Jamie F.]

Is there a resource to look up what a screw part number translates to in regard to the screw specs?
I know that many of the screws that GM gave part numbers to in the '69 assembly manual are common phillips head sheet metal, or machine screws. If I knew the type, thread, length, head type, etc. that the part number refers to it would be so much easier to get the right screw!

for example what is a 3843505? That is the rear compartment frame attaching screws, I don't know what they are suppose to look like.

[Jack H.]

Re: Screw Number vs. Screw Specs

I don't know of any good + complete data base that's available to us... GM does have drawings/specs in the drawing system, but we're not able to access the system except through the help of an insider here/there.

Plus, on fasteners, a given part number can translate into a WIDE range of suppliers who were qualified over time (coming and going) whose indivdual parts differed in physical appearance from each other (plus themselves as their screw machine tooling wore out and was replaced/improved).

Then, you have the complication of which supplier's part(s) were actually in stock/on-line at St. Louis when a particular car rolled down the line or at Flint/Tonwanda when a given engine was assembled. GM had multiple manufacturing facilities spread across the US, and some sites might have preferred this/that supplier's fastener over another equally qualified source due to considerations like freight-in costs...

So, in the area of fasteners, what's right/wrong and actually factory correct/original, remains a grey area that's part of the ART aspect of the restoration/preservation hobby... If you're looking for an unambiguous data base to spit out 'correct' answers, it doesn't exist!

[Reba W.]

Re: Screw Number vs. Screw Specs

Jack's reply points out the reason that most JGs do not specify fasteners other than by finish.

To find what you need, Jamie, find an original car and ask the owner to let you examine it.

[Roy B.]

Re: Screw Number vs. Screw Specs

IF your asking about C1's every Corvette I've ever had use these . Gm drilled the hole smaller then the needed screw size, then used self cutting & taping screws .Rare finding them if you don't have them.

[Loren L.]

Re: Screw Number vs. Screw Specs

Back in the 60's (?) GM removed Group 8.900 and issued the "Standard Parts Book" - find one.

[Jack H.]

Re: Screw Number vs. Screw Specs

I have Section 8.900 in my copy of the 2-book, 1961 Parts & Accessories Manual. It's VERY basic and insufficient for restoration work.

You'll find the various fasteners listed by GM PN with an OCASSIONAL, and generic picture; a thubnail of X-Y dimensions and NO mention of head marks, qualified suppliers, various differences in fastener finish and/or other geometry aspects (e.g. hex head recessed vs. 'high hat')...