Bolts for Pickup Box to Frame (1939)

[third_edition]

Hi All,

I am hoping someone here can help me out...

The box on my 1939 P/U rests on boards which are bolted to the frame. In between the boards and the frame, the truck uses Wooden cross members which raise the box up off the frame at the front and at the rear.

I believe carriage bolts, about 8" long, are used to hold this all together. They appear to be 7/16" diameter (hard to say as they are pretty much non-existent now).

My problem is that I have searched high and low for 7/16" x 8" carriage bolts and have had no luck in sourcing them. This seems strange as they are available in 3/8" diameter and 1/2" diameter (the guy at the fastener store says that nobody uses 7/16").

I would not feel safe holding the bed in place with 3/16" and 1/2" is too big for the holes in the steel part of the frame.

Does anybody know where I can get these?

thanks,
George

 

[Mart]

I used metric on my 41. Not sure if I used 10mm or 12mm. Would something like that be more available there?

 

[tomcarman]

Try this link.

https://www.google.com/search?q=7/1...1080&bih=572&dpr=1.78#spd=6087100932215364682

 

[38bill]

You could always go with a kit if you cant find them locally.

https://www.horkeyswoodandparts.com/page27.php#boxoframe

 

[DavidG]

Michael Driskell at thirdgenauto.com likely has them in the correct length and thread count.

 

[third_edition]

Thanks to all of you for your help - BTW, I talked to Mike and although they used to sell these (they were in the old Roy Nacewicz catalogue) he had to discontinue them as they were almost impossible to source / manufacture for a reasonable price.
Cheers,
George

 

[oldandtired]

Do the long bolts you are looking for to use on your 39 have the square hole in the top like the ones used on 35-37 pickup beds?

 

[rockfla]

Thanks to all of you for your help - BTW, I talked to Mike and although they used to sell these (they were in the old Roy Nacewicz catalogue) he had to discontinue them as they were almost impossible to source / manufacture for a reasonable price.
Cheers,
George

George
Bolts are my business. Mike and I have had conversations about these particular bolts you require......THERE are two major issues you are facing. 1) The "majority" of fastener suppliers and fastener manufacturers are producing products for the "Industrial" market NOT the "Automotive" market and 7/16 & 9/16 are NOT commonly used diameters in the "Industrial" world (IF at all) . WHY automotive manufacturers/Engineers use 7/16 & 9/16 I have NO clue......WHY they just can't either increase OR decrease the diameter of the bolt is beyond me??
2)There are a few manufacturer's I deal with that could "certainly" make these items, NO problem......The problem lies in the quantity. The "cost" of set up of the machinery to make them is "HIGH" and the quantity needed for "stock" is cost prohibitive.......SO its a "demand" issue, Unfortunately!!!!! AS you can figure, the amount needed to make the price palatable would supply the need for two life times of demand.



This doesn't help you I know BUT this is how it is!!

 

[Kube]

When I needed these for the '40 pickup restoration I'd done, I'd purchased the reproduction bolts from Mac's. They were of course, much too short for the required application but had the proper head, diameter and thread count.
It was an easy task to cut the "center section" out of the repop bolts, weld in the additional length of shaft needed, re-plate and done.

 

[Tinker]

Do the long bolts you are looking for to use on your 39 have the square hole in the top like the ones used on 35-37 pickup beds?

On the 38 truck there was the square tool flat top bolts. 38-39 share a lot of the same items. 38 had a metal bed floor. Not sure on 39. When I was looking for them, a long while back. Roy told me they are not being made by anyone.

In a coffee can I have most of the original bolts, some had to be cut out. There is a cast wegdes also to square the bolt to the frame. Kube makes a good point that with a cutoff and a tig you can salvage for an original look. Or just use the best that are available currently.

 

[rockfla]

IF someone has the "correct" length (OR If it is for sure 8") I will be happy to check with my two specialty manufacturers and see just what they would cost to have made...what the quantity break might be....etc etc. AS for the thread count I don't think that would make a difference being course thread instead of Fine, correct??? AS course thread is WAY more common in my world of fasteners.


HOW many per truck are needed to, that way I can figure a quantity based on a sets of them??

 

[tubman]

Come to think of it, I can't remember ever seeing a fine-thread carriage bolt.

 

[Kube]

Come to think of it, I can't remember ever seeing a fine-thread carriage bolt.

Oh yes... many applications. Body to frame on '39 & '40 Fords are the ones that come to mind immediately. Also, the ones utilized along the exhaust system.
The bed to frame bolts (PU) are fine thread as well.

 

[rockfla]

Oh yes... many applications. Body to frame on '39 & '40 Fords are the ones that come to mind immediately. Also, the ones utilized along the exhaust system.
The bed to frame bolts (PU) are fine thread as well.

That is automotive for you!!

 

[GaryU.]

My turn! These are the remaining original bolts from my '39 pickup bed. I was there on that day when my "pop's" and brothers thought we should take the fenders, running boards off my pickup that was used on my Grandparents farm. This happened in 1981 best I can guess. Since the other pieces were off we proceeded to remove the bed bolts as well. Wish we had never done this as the pickup, although being very abused, was mostly original. I have a repro bed with the inaccurate wood floor instead of steel per my wishes but still have one side of those original bolts. Front most is a long carriage bolt while the rest have the taper top with the square indentation for tightening, all fine thread. Hope this helps.

 

[petehoovie]

My turn! These are the remaining original bolts from my '39 pickup bed. I was there on that day when my "pop's" and brothers thought we should take the fenders, running boards off my pickup that was used on my Grandparents farm. This happened in 1981 best I can guess. Since the other pieces were off we proceeded to remove the bed bolts as well. Wish we had never done this as the pickup, although being very abused, was mostly original. I have a repro bed with the inaccurate wood floor instead of steel per my wishes but still have one side of those original bolts. Front most is a long carriage bolt while the rest have the taper top with the square indentation for tightening, all fine thread. Hope this helps.

 

[rockfla]

My turn! These are the remaining original bolts from my '39 pickup bed. I was there on that day when my "pop's" and brothers thought we should take the fenders, running boards off my pickup that was used on my Grandparents farm. This happened in 1981 best I can guess. Since the other pieces were off we proceeded to remove the bed bolts as well. Wish we had never done this as the pickup, although being very abused, was mostly original. I have a repro bed with the inaccurate wood floor instead of steel per my wishes but still have one side of those original bolts. Front most is a long carriage bolt while the rest have the taper top with the square indentation for tightening, all fine thread. Hope this helps.

Could I get just a picture of the head of the "other" bolt, they appear to be a "bucket tooth" bolt???? AND how far is the 8-1/2 carriage head bolt threaded??? about 1-1/2"'s or just shy??

 

[GaryU.]

Not a "bucket tooth" bolt on the the 3 tapered head bolts, a smooth taper on all. You got the thread length correct on basically all the tapered head bolts 1 1/2 inches give or take a bit with the long carriage bolt having threads of 1 3/8 inches.

 

[Tinker]

Great post GaryU and pictures.

 

[third_edition]

Thanks for everybody's input...

I've decided to TIG weld a set of bolts for my truck. I can get the exact length I need and use fine thread "donor bolts". I will fab up a little "jig" to ensure they are straight. I can get Grade 5 Carriage Bolts which should suffice.

Cheers,
George