Thread: How to build an early hotrod frame

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I'm in south Texas. I have a 29A sedan. I bought the square tubing yesterday. i went ahead and bought the 2X4 1/8" only because that seems to be the most common size used on other builds. I started on channeling the body using 1" square tubing. I am channeling it approx 4" so whenever i mount the body on rubber washers it will keep it a little above the frame so the frame drags and not the body. I am kinda hesitant about starting on the frame without the front end or engine. so i will probably wait till i can find a cheap V8 donor car. I'm going to go ahead and order a spring behind front end from speedway for a suicide front end. But I'm not sure what bolt pattern to get either 4 1/2 or 4 3/4 are the options. thanks and any advice would be appreciated. Does anyone have pictures of there channel work on a sedan?
xjustjeffx2002@yahoo.com

Hi Jeff---Nice to hear from you. There are thousands of build pictures on
the HAMB showing the channeling process. Use the search function to find
them. As far as the bolt citcle pattern, you have 2 choices #1---wait
untill you get a rearend and then buy whatever matches it, or--#2---do like
I do, and buy whatever you want. Wheels are available for any bolt pattern,
and if the rearend you end up getting has a different bolt pattern, don't
worry about it. Since most hotrods have dramatically different front and
rear wheel/tire combinations, most rodders don't carry a spare tire anyways.---Brian

Jeff

You might touch bases with a guy who posts here occasionally who is in Corpus and is building an "A" coupe. He signs "Aster" and he's one of the good guys.

Pick his brain a little.

He hasn't posted lately but I'm sure he's still around. If you can't make contact with him let me know (send me a PM) and I'll send you his e-mail address.

Or, failing that, I'll suggest that he contact you.

Good luck with the project.


Jim

Jeff: You are being smart to get your components first, then build your frame to accomodate them. That way you leave enough fan clearance, etc.

You might want to build your frame from 2 x 4 lumber first, as I do, it allows you to approximate the look of your real frame, and you can easily make changes in the lumber until you get exactly the stance and look you want. Plus, $10 gets you more than enough lumber and sheet rock screws to build one. When you are done with it, cut the lumber into short pieces because they come in handy to act as shims and supports while building the car.

And, although it is a major hit up front, I like to have my final tires and wheels on hand when I start the build. It sets the stage for the final appearance and stance, and is the only way to know how it will sit.

Just an idea.


Don

Don has it right about the wheels and tires. Actually, if you know what tire size you are going to run, the tire shop that changes a lot of tires daily will give you an old set of skins of the exact size that still hold air, but have a lot of tread wear. This tread wear will not be enough to alter the stance of your "being built" car, and as your build progresses over 2 or 3 years, the primer paint and weld burns won't matter to the old tires. then swap the tires out for new ones when your build is finished.

I would like to thank everyone for there help. I'm sure i will need ALOT more before i am done with this build. i like the using 2X4 lumber idea, but isn't a 2X4 really 1 1/2"X3 1/2"? its been to rainy lately for the wreckin yard to get my rear end out of the truck, hopefully Monday while I'm there maybe i can luck into some wheels.

Yeah it is not a true 2 x 4 anymore, but close enough to give you the general look and fit of the real stuff. Or, if you want to get real fancy, you can buy 4 x 6 lumber and mill it down to.........................


Don

Brian,
I've had many questions for you in the past and after two years I'm finally putting my 26 T coupe together. It's got a Buick V6 (just setting in the frame for weight), 373 geared S-10 rearend with drum brakes, modified prostreet frame, Super Bell 4" I beam Dropped axle with a four Bar and GM Metric front disk brakes.
I found an artical from you about Vega steering that stated that the steering box is to be mounted so that the input shaft is tipped UP at an angle of 10 degrees from the frame at the rear side of the steering box.
Questions: The frame sets at an downward angle, so do I add the angle of the frame to the 10 degrees?
How far forward should the box be located?
How far down in the frame should it be located?
Along with that question should the Drag Link be parallel with the Tie Rod?
What about steering stop nuts are they still used?
If there are any pointers you can give me I'll take them. Thanks for all your help!!!
Tom

Tom---Nice to hear from you.
The ten degrees ‘tipped up” angle is from the frame itself---don’t worry about what “rake” the finished car will set on.

A Vega box in a model A frame is located so that the 2 bottom bolts which will come thru the mounting plate just clear the underside of the frame rail by enough to get the nuts on them. The top bolt doesn’t get a nut---it will be almost in line with the top of the frame, so you will have to drill and tap the spacer which fits on the engine side of the nounting plate, between the mounting plate and the steering box---there is no room for a nut on the top.

The “fore and aft” positioning of the steering box is detemined by the length of Pitman arm that you are using.---I always use an aftermarket Pitman arm which has the taper reversed at the outer end so that the drag link assembles to the underside of the Pitman arm to give me adequate clearance between the drag link and the underside of the pan).----When viewed from above, with both front wheels facing straight ahead, the drag link should be parallel to the tie rod---this will determine how far back your steering box is mounted in the frame from the front crossmember.

I don’t use stop nuts on the cars I build---generally the Vega box will run out of movement before the wheels turn far enough to hit anything anyways.

Good luck---Brian

Brian,
Thanks for the info.
More questions:
With my spring over 4 bar setup will I need Adjustable Spring Perches or should I cut re-weld the front crossmember to the 6 degees that's needed? I need to do some work on the crossmember anyway.
The spring fits into the crossmember really tight (had to jump on the crossmember to get it down and in place) is that too tight?
I will be using a stock tall 26 T radiator shell, other than buying a expensive Walker radiator, are there any other stock ones that will fit? I've got one from a 66 Mustang but it just doesn't fit the greatest.
Tom

Adjustable spring perches are nice, but they are spendy. I generally tell people that if the 6 degrees caster is not built into their crossmember to just use a shim with the 6 degrees machined on it and to sandwich the shim between the top of the spring and the underside of the crossmember.--However, if your spring is a real close fit into the crossmember, then probably the adjustable perches are your best option. As far as rads go, take the grillshell down to your neighbourhood rad shop---they will have a bin full of old top and bottom tanks. find a set of tanks that fit your grillshell and have them build a new correct length core to suit what youv'e got.---just be aware that on any grillshell earlier than a 32, there is no "grill" to cover the radiator, and if the tanks are visible from the front, it will look uglier than shit on a stick.

How long should my radius rods be??? My knowledge of radius rods is that yes, longer is better. Main reason for that is that the longer a radius arm is, the less movement back and forth on the axle being guided as it swings up and down thru the arc of travel. I find that the ideal point of attachment for rear radius rods is to the crossmember that supports your transmission tailstock, or up to about 10" behind it---and the closer together you can keep the ends attached to that crossmember, then the better your suspension will work. On the front, there is one caveat to remember---If you are using a cross steer (Vega) style steering set-up, then yes, longer is better. If, on the other hand you are using a steering drag link that runs from the steering arm up to the drivers side spindle, it is wise to keep the rear attachment point of the front wishbone in line with the point where the Pitman arm attaches to the drag link, when wheels are pointing straight ahead, when viewed from the side. That way, as the front axle moves up and down thru its suspension travel, the arc described by the influence of the wishbones will be equal to the arc described by the drag link as it pivots on the end of the Pitman arm, thus minimizing bump steer.---Brian

that is some sweet work and rendering

THE FOLLOWING RESPONSE WAS TO A GENTLEMAN FROM IRELAND, WHO WANTED TO KNOW THE PROCEDURE FOR "PINCHING" A MODEL A FRAME AT THE COWL: Hello James---Welcome to Canada---Your not intruding. I am going to assume that you still want the stock width front and rear crossmember, and that you plan on some custom body mounts.---The body mounts are an angle that set on the outside edge of the frame, so if you suck the frame in 1" per side, the outstanding leg of the angle, along with the holes in it will have to be extended by 1" to maintain the same position relative to the body. Since all of the other crossmembers will be removed except the rear crossmember and the front crossmember, you could conceivably use a boat builders clamp at the point where you want the narrowing to occur, and start tightening.---A boat clamp is a pair of castings fitted to a peice of 1" pipe. one casting is the moveable jaw, and can be slid to whatever length you need,then locked there, the other casting is attached to one end of the pipe and has a moveable jaw which is moved along parallel to the pipe with a crank mechanism and an acme thread. (I have a pair and can send you a picture if you want.) You do not say if the frame is boxed or not, (I hope not) and will structure my answer based on the assumption that it is not boxed. The big trick is to be sure that you bend each frame rail by exactly the same amount. I would set the frame up on 4 boxes about 16" high at each of the 4 corners and level it and check for squareness before I started bending anything. Use a plumb bob and a chalk line to establish a centerline on the garage floor that clearly marks the centerline of the frame on the floor. Use an oxy acetylene torch with a big cutting tip or a rosebud tip, and heat one frame rail at a time to a cherry red in a band about 2" wide exactly where you want the bend to be, before using the boat clamp. ---Be especially sure to get a lot of heat into the top and bottom flanges, as this is where the most resistance to bending will be. As soon as one frame rail is cherry red, put the boat clamp on, and start tightening untill the heated framerail moves in the required amount---It will bend very easy when heated to cherry red, and the unheated framerail will not bend. Be very carefull during this operation that you do not move the frme around on the boxes relative to the centerline, as this is your "witness mark". You will need a 24" level, and probably a carpenters square, to measure exactly how much bend is enough. Leave the boat builders clamp in place, and walk away---let everything cool for an hour. go have a beer. Then come back and remove the boat builders clamp. and repeat the heating and bending operation on the other frame rail. Measure, measure, measure, and then measure one more time to be absolutely certain that you have bent both frame rails the same amount, relative to the centerline. Walk away---leave it for an hour. Do NOT quench the heated rails with water, oil, or blasts of air. that should get it done---It wouldn't hurt, if after everything is levelled, but before you start the heating and bending, to place a 100 pound bag of sand on top of the frame rail at each corner where it is supported on the box. This will lessen the chance of inadvertantly bumping the frame with your knee and moving it away from that very important centerline, and will also ensure that the frame stays flat and level during the heating process. I would also put in a temporary support under the frame rail about 12" on either side of the zone where you are doing the heating on each frame rail, so that they don't "sag" under their own weight when heated to cherry red.---Brian

thanks so much, that will come in really handy!!!

This thread is the bomb! Don't know how I missed it before. I've got a scheme cooking in my head for after my current project is done; this will help immensely.