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-   -   4"x2"x3/16" tube frame (http://www.hotrodders.com/forum/4-x2-x3-16-tube-frame-227997.html)

DeeW 01-05-2013 04:36 PM

4"x2"x3/16" tube frame
 
I am building my own frame for a 1941 Ford 1/2ton pickup truck, chopped 4 1/2". I am also building my own short box. Front end will be straight axle ,4" drop, spring over, reverse eye., 350/700R4 setup. I ordered a set of Plans from Hugh's Rat Shack on EBAY for 20 bucks. That was a waste of 20 bucks as Youngsters has free plans with more info. Question is, what is a good centre to centre width for this frame?

Gus's 40 01-06-2013 08:21 AM

when I built mine for a 40 chevy cab I measured from the original rear body mounts in the cab and ran the frame tubing to the outside of the holes and and had to reinforce the fronts because the amount of taper in to get the width I needed for the front cross member wouldn't work with the original front ones. I used a model a front cross member that's what determined the width of my frame

Gus's 40 01-06-2013 08:59 AM

3 Attachment(s)
the front of the frame at the back side of the cross member is 24 inches measured inside the rails and at the back of the cab its 36 inches

ogre 01-06-2013 09:35 AM

i've never built a frame, but i'd think that 4x2x3/16 would be very heavy, unless your making a heavy hauling or tow vehicle.
4x2x1/8 would weigh a third less, be as thick as the stock frame and a lot more structure than the stock C-channel frame

Gus's 40 01-06-2013 09:41 AM

it is a little heavy but I figured since its 2x4 instead of 2x6 I would use thicker material, my truck weighs 2500 with me in it

DeeW 01-06-2013 12:07 PM

4"x2"x3/16"
 
I think 3/16" is a good choice. Remember, pot holes,road kill, etc. Also the Plans I bought on EBay from Hughs Rat Shack in NM are no better than the freebie Youngsters Plans and were incomplete along with a non existent web site.........hmmm....... anyways, 20" is the standard front inside rail measurements for a 350 set up that I have concluded from various sites. Having never constructed a frame before, does this sound right. I am running a 4" drop straight Speedway front end with spring over, reverse eye on a front perch.

Gus's 40 01-06-2013 01:01 PM

thats what I have the speedway 4 inch drop reverse eye spring over and I got a 2 inch drop model A cross member from them also. I probably could have got it to 23 inside width I didnt trim anything off the cross member I ran it inside the frame against the inside of the frame rails then boxed all around it. That left me plenty of room for my steering and if I ever went with block huggers and full exhaust to clear with no problems

techinspector1 01-06-2013 02:36 PM

Position the body and bed, front axle and rear axle mocked up on your fixture, then use frame rails to tie all of it together at the ride height you want. You may not know that you can "Z" the frame rails in any manner you want them to achieve a low or high ride height. Don't wait until you have built the whole frame and then have to jump through hoops to get the car at the ride height you want it to be. Plan ahead. Also, one of the most common mistakes I see when building a truck with a bed is that the cab and bed are not parallel. Eyeball the profile of the pair and tilt the bed up or down to match up with the beltline of the cab. The finished product will be much more pleasing to the eye than having the cab and bed non-parallel. For the rest of you guys, 2" x 4" x 0.120" wall rectangular steel tubing will be all the strength you need in this type of project.

1971BB427 01-06-2013 08:00 PM

I totally agree with the tubing size Techinspector posted! There' no reason on earth you'll need thicker than 1/8" or .120" tubing for any street vehicle or even offroad, unless it was going to see extreme abuse. Even then it would just need more bracing, not thicker wall tubing!

Gus's 40 01-06-2013 08:07 PM

how thick is an original frame? seems like when I boxed the model A frame it was thicker then .125 but I could be wrong

1971BB427 01-07-2013 08:47 AM

Most factory frames are even thinner than .120"

techinspector1 01-07-2013 01:18 PM

Quote:

Originally Posted by Gus's 40 (Post 1631581)
how thick is an original frame? seems like when I boxed the model A frame it was thicker then .125 but I could be wrong

It has been a long time since I was around any early frames, but I seem to remember that Henry used either 11 gauge or 10 gauge steel.
Sheet Metal Thickness Gauges
He used "C" section channel though, not closed tube material like we normally use today. For many years, hot rodders have used boxing plates to close in the fourth side of the channel for strength.

Autoweld has capability to mandrel bend most of the boxed materials that we would use today......
Auto Weld Chassis Components Racing Manufacturing Chassis Products, 9" Ford Housings, 2x3 2x4 Mandrel Bent Frame Bending Danville PA

In the past, I have used the method of sawing through 3 sides of the box, bending it on the cut and welding it back solid. You can make acceptable bends in this manner at home, with several cuts. The number of cuts you make and where you put the cuts will determine the amount of bend you can achieve. The cuts must be made perfectly perpendicular to the run of material though, or you will end up with a pretzel. Ask me how I know.

jaw22w 01-07-2013 04:00 PM

I like to use 3/16" so you can tap the rails for brake line clamps, fuel line clamps, etc.
You mention 20" as the width of the frame. This is actually too narrow for a 350. My frame measures 23.25" at the front of the engine and tapers to 27.5" at the cowl (inside dimensions). The mechanical fuel pump is only 1" from the frame rail and the low mounted alternator is about 1/2" from the frame rail. This is on a 27T, so the car is narrower than what you have, but you still need the space for your engine.

1971BB427 01-08-2013 08:41 AM

Quote:

Originally Posted by jaw22w (Post 1631891)
You mention 20" as the width of the frame. This is actually too narrow for a 350. My frame measures 23.25" at the front of the engine and tapers to 27.5" at the cowl (inside dimensions). The mechanical fuel pump is only 1" from the frame rail and the low mounted alternator is about 1/2" from the frame rail. This is on a 27T, so the car is narrower than what you have, but you still need the space for your engine.

20" is too narrow if you're going inside the rails with headers, or using a mechanical fuel pump, and keeping the engine low in the rails. But my frame is that narrrow and I'm using fenderwell headers and an electric fuel pump, and it fits great.


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