30/31 subrail dimensions

C

claybob

Junior Member
So I've got my new subrails, cross sills, body blocks, etc. and am mocking up. The new rails come undrilled. I have SOME of the old subrail so the front section is pretty obvious. The rear on the other hand, not so much. So, a couple of questions:

Where can I find a detailed subrail schematic (including holes)?

Each block appears the be bolted through the frame and passes through the cross sills with the possible exception of the rear two. The most rear must bolt through the subrail itself - Right?

The one directly north (or south depending on your orientation) looks like it could either bolt through the subrail or be captured under the subrail and bolted through the cross sill, or maybe both? Does anyone know which is correct?

Thanks in advance
 
Bob, I ordered one from Bratton's. It'll take at least two months to make and ship. Is this what I've got to look forward to? The sub frame on my Town Sedan is so bad, I can't reliably position anything off it. The wood is disintergrating to powder. I can "jig" the holes off some parts, but all? The new wood is coming from North Carolina, is that the same manufacturer?
Terry
 
I replaced the wood in a '31 Chevy truck cab recently. To get some idea of where the sub frame went, I transfered the body mounts to a sheet of 3/4" plywood. This seemed to work out pretty good but I learned quickly NOT to finialize anything till all parts where paced.

Ron
 
Terry,
Yes, i think this IS what you get to look forward to. Like youngster, I have chosen the plywood method. Agreed, not welding 'till it all fits. I've got posts on multiple forums regarding sub rail dimensions but to date, no real help. I did not get my rails from NC, but rather MACs. I've also done business with Snyders. Both are great, FWIW. Good luck to us all!
 
OK, so obviously no detailed subrail dimensions. How about someone with a 30-31 coupe take a couple of measurements for me, please?

Subrail width (outside to outside) just directly behind the A pillar...
Subrail width directly in front of the B pillar...

Thanks
 
bobmc,
Thanks for the attempt. I've got these (and many more) frame dimension blueprints but was looking for the same on the body subrails - Seems to be quite the elusive data. I appreciate the help eother way,
Claybob
 
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While Bob's dwg is a immense help, I realise what I'm missing. Looks like we're in the same boat. The body has just too much flex to reliably take dimensions off of it. We need prints.
Terry


claybob said:
bobmc,
Thanks for the attempt. I've got these (and many more) frame dimension blueprints but was looking for the same on the body subrails - Seems to be quite the elusive data. I appreciate the help eother way,
Claybob
Click to expand...
 
claybob,

I don't know what A and B pillars are, but the first 3 pictures show the cross subrail at the rear of the door pillar. The top outside is 42-1/4" and the body bolt hole is 5" from the top outside.

The 3rd and 4th pictures show the cross subrail at rear of seat and front of rumble/trunk floor pan is 42-13/16" top outside and the holes are 5-1/4" from top outside.

FYI, the inside was media blasted, metal prep sprayed on, rinsed with water, and blown dry with air hose. This was a year ago. The surface rust/tint has not changed in a year.

This is a 1930 coupe. If you need other dimensions, show me a picture or something of what you want.

Mitch
 

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BobMC, I have a 30 Town sedan. Is there a chance the dimensions are different for a TS than a Coupe? Almost none of the dimensions given agree with the actual dimensions. The space between the rear crossmember is given as 22 1/2". It's 28' on mine. The distance between holes on my hood latch mount is 1 5/8" and to verify this dimension, I checked the hood latches themselves, 1 5/8 ", And many other dimensions aren't the same too. I'm sorry, but this just doesn't work. It looked so good in the beginning too. Thanks for trying!
Terry
 
I agree with Terr, NJ that some of the frame dimensions given above are wrong. The only one that I measured was the rear body bolt location. I checked 2 frames and got 41 inches, not the 40 1/2 suggested by the posted diagram.
 
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