side sub rails yay or nay

Would it make any sense to buy new side sub rails (the one that go along the length of the sides) If I'm going to in stall a steel sub floor? do you weld your body panels directly to the new sub floor? and eliminate the rusty side rails?
Thanx

 

If you are refering to the Model A in your avatar, the car originally had a complete subframe assembly. The subframe consisted of the side sub rails (the one that go along the length of the sides) that you are referring to, and four cross channels including the one at the rear under the trunk. The body sheet metal was attached to the subframe which in turn was attached to the frame of the vehicle. The subframe, first and foremost, gave rigidity to the body to help it maintain it's shape, and secondly to provide a way to attach it to the frame and also support a floor. In most of the Model A's found in the rust belt, the subframe, or whats left of it, is usually in pretty sad shape.
Some choose to repair the rusty side sub rails and cross channels, others choose to replace them with store bought pieces and still others choose to fabricate new subrails and cross channels from scratch.
If the new subfloor that you are refering to includes structural shapes such as square or rectangle tubes that replace the subframe, I'd say go for it. The most difficult piece to fabricate is probably the door sill (the part you see when you open the door) as it is a part of the side subrail.
As for me, I plan to repair the forward part of my subframe rails, replace the cross channels with store bought pieces, and fabricate new side sub rails from the rear wheelwell back... Then I'll install a sheetmetal floor over that... Hope this helps...

 

Yes the car is A in my avatar, I plan on going from scratch with square tubing, and sheet metal over that. I guess the hard part like you say is making the contour around where the doors are. I plan on using 1x1 for most of it and 1x1-1/2 for stress areas, maybe use the 1x1-1/2 to shape the side rails also. I think I might have to cut out the old subs for a pattern but an afraid I'll loose my original shape of the body, or I could use card board and make a pattern first.

 

Yes, unless you are experienced,crafty or lucky you need the subrails. They also form the inner rocker where an A door shuts against...loosely

 

Subrails are a good thing to have. Alot also depends on what frame you are using.

 

Using an A frame

 

You will probably save a lot of time and headaches by using the replacement sub rails available especially since you are still using an A frame.


http://www.jalopyjournal.com/forum/showthread.php?t=409232

 

Are you going to channel it? If you're putting the body on the frame, I would say go with the store bought subrails. If you're channeling it you could go either way.

 

How do you guys mount the sub-floor to the frame? does anybody use rubber mounts to keep vibration down?

 

you can buy rolls of welting that go between the frame and subrails

 

Yup, I see that stuff at all the Model A websites, but wouldn't rubber mounts be better? maybe 8 of them spread around the frame, sub-floor would be say 1/2 to 1/4 inch above the frame. all of the newer cars trucks etc. have them, why wouldn't one want to up grade?

 

i was luckey to have a rust free car to start ...
back in 65 i was the 2nd owner!!!
photos floors from Direct sheet metal here in socal...
most of what you see for sale comes from them...
great fit...........will make custom sheet from your drawings/alum also....
......... sheetmetal.com .........