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Technical Building a Model A Frame from Scratch, Who’s Done It ?

Discussion in 'The Hokey Ass Message Board' started by chev34ute, May 30, 2022.

  1. chev34ute
    Joined: Nov 13, 2011
    Posts: 1,142

    chev34ute
    Member

    Hey Guys.

    I am just wondering how many out there have built up their own Model A Frames.

    What kind of steel did you use ?

    How much did it cost ?

    How did you source the measurements, blue prints or from an original frame ?

    Did you build it stock style or with a stepped up rear ?

    Did you use a jig or rely on a level floor to get all the sections squared up ?
    Images below are for inspiration.
    2FAD9EA8-9863-456E-AA85-CADFC3B689B2.jpeg 848123B0-F868-4F7F-8F4C-67381F271FF2.jpeg 0FBB337E-732E-4A0B-86F6-C1CCF48DBC30.jpeg



    I am including a couple of images for inspiration.
     
  2. Yeah, I made some. Start with 4 x 2 (100 x 50 x3mm) box tube and a repro front crossmember. Taper the rails where appropriate, put the kink in the right place, form the horns how they're supposed to be.

    Rear and middle crossmembers and kick up if any depending on the suspension and driveline.

    A flat floor, stringlines, keep everything square, level and held down.

    This is one. The only pic I have handy.
    small file.jpg
     
    Last edited: May 30, 2022
  3. Copied a bent Model A frame using 2x4 10 ga tube. Tapered the front and made the frame horns from flat stock. Made the front cross-member from three pieces of 1/4" flat, a center cross-member out of tube, and an A rear cross-member. I laid a 4'x8' 3/4" plate on a couple horses at work and built the frame on it. We built this for a fender car so it was set up for running board and fender braces. Steel was under $100 for everything; but it was 40 some years ago. Still have drawings and patterns. Last A's I've worked on, we used boxed stock frames.
    mikes a chassis.jpg
     
  4. chev34ute
    Joined: Nov 13, 2011
    Posts: 1,142

    chev34ute
    Member

    Wow I did not realise steel was that expensive back then. I am pretty sure I could build a frame for a couple of hundred if I needed to. At the same time, original frames here are very expensive starting at $800.
     

  5. Blade58
    Joined: Mar 5, 2012
    Posts: 355

    Blade58
    Member
    from apopka ,Fl

    Steel prices has doubled post Covid
     
    fiftyv8 likes this.
  6. alchemy
    Joined: Sep 27, 2002
    Posts: 18,291

    alchemy
    Member

    Around here you can buy a perfect A frame for less than the steel to make one from scratch.
     
    RICH B and continentaljohn like this.
  7. continentaljohn
    Joined: Jul 24, 2002
    Posts: 5,306

    continentaljohn
    Member

    I built a few model a frames using 2x4 10 gauge and .156 wall . I used a large machine table that was leveled out and built it on it. I used a original frame as my measurements as i had a super nice on. The only reason I built one was to Z the rear 14 inches and sweep the front. I used original crossmember in the build along with a 40 x member cut down. It worked good and will see if I have Polaroids of it lol.
    With the price of aftermarket rails such as JW rods I don’t think building a stock type frame is cost effective unless it’s just bragging rights.
    It’s amazing to me how many model a frames are available cheap as well.
     
    RICH B likes this.
  8. Just checked one of my usual steel yards; 2"x4"x3/16" was $331.41 and 2"x4" 11 ga was $235.75 for 24' sticks. I'd probably do a little more shopping around these days; but prices for new steel has always seemed pretty even. Missing the days when I could just order my tube in with a couple tons steel for the truck shop.
     
    continentaljohn likes this.
  9. jaracer
    Joined: Oct 4, 2008
    Posts: 1,699

    jaracer
    Member

    I built mine out of 2 X 4 mild steed box tubing. I used an old frame as a guide to set up a homemade jig on a large flat table. I tapered the front section a bought a pair of reproduction front horns. I bought my front cross member and made the back one (non-Hamb approved). I put the kink in the middle by sawing almost through the tubing in 3 spots and bending the kerfs closed. I then welded them back up. If you take out the front cross member I bought (non-Hamb approved), I think I had about $450 in the tubing for the main rails and cross members. However, that was in 2008.

    Because I used tubing instead of "C" channel, one of the problems was how to secure the body bolts. Somewhere I saw a guy take a stepped bit and drill a hole part way through the top of the tubing just large enough for a flanged nut to drop in and be flush. He then welded the nut to the tubing. I liked the idea, but wondered how strong it would really be. I had a lot of left over tubing so I tried this method on a short piece. After I was done I tried to break the nut free of the tubing. It took a lot of force and when I finally got it to fail, it was the tubing itself that fractured. Based on my test, that's the way my body attachments are made.

    Also, since I had a straight stock frame, I used it for all my dimensions. To get attachment holes in the correct position, I made an 1/8 in hole in the top of the stock frame at the front axle center line. I measured the same distance back from the frame horn back to make identical 1/8 in holes in the new frame. This then became my reference point to transfer dimensions (station zero). I used a trammel bar to measure and transfer the locations. It worked out great.

    Somewhere I have pictures of the frame set up on my jig. However, I can't find them. I'll post pictures if I find them.
     
    continentaljohn and Algoma56 like this.
  10. A quick online check shows AUD$233 (that's USD$167) for an 8 metre length of 100 x 50 x 3 mm. Plenty.
     
  11. X-cpe
    Joined: Mar 9, 2018
    Posts: 1,504

    X-cpe

    DSC00544.JPG

    Started this 40 years ago. Only guide was HRM (esp. XR-6) and the wheelbase. The body I have had no sub-rails, no firewall, no rear inner fender wells or decklid. I was able to go pretty much free form. Local welding/fabrication shop folded me two 3"x3" angles out of 1/8" plate for sub-rails. Since I was going to Z it I sold the frame for more than the steel cost. Bought a piece of 3"x3"x3/16" square tube. Turned that into channel on the table saw in the wood shop with metal cutting blades. Laid out the shape of the rails on the shop floor with a chalk line. Leveled and squared the rails on cinder blocks and shingle shims with a level and tape measure. Pie cut the rails vertically at the fire wall and capped them with a wedge shape to taper the front frame rails. Boxed it with 1/8" plate. Used a buzz-box welder. Been 25 years since it was on the road. Back on it now. With what I know now I could do it a damn sight easier.
     
    Last edited: May 30, 2022
    continentaljohn likes this.
  12. lostone
    Joined: Oct 13, 2013
    Posts: 2,076

    lostone
    Member
    from kansas

  13. chev34ute
    Joined: Nov 13, 2011
    Posts: 1,142

    chev34ute
    Member

    They are not that cheap here in Australia, it all comes down to economies of scale, there were millions of Model As sold in the US as opposed to tens of thousands in Australia, there are more Rod builders than there are original A frames, so prices are going to be higher.
     
  14. chev34ute
    Joined: Nov 13, 2011
    Posts: 1,142

    chev34ute
    Member

    I was just reading through the build thread and I have to say thats impressive workmanship, especially extending the length of the rails. I also like the commercial Model grill you are using, I have one like it myself along with a commercial 32 grill.
     
    lostone likes this.
  15. continentaljohn
    Joined: Jul 24, 2002
    Posts: 5,306

    continentaljohn
    Member

    We have the other way around as a lot of guys are using aftermarket market frame and selling the original ones for 1 or 2 hundred bucks. I will say as time goes on less old stuff is showing up at shows and swaps.
    Too bad shipping is crazy expensive as we could drill and pop the rivets out and send you a few.
     
  16. Wonder if these piles of repop A frames are still down in Argentina. Kinda a neat Z on the one.
    A  frame stack 2.jpg A frame stack 1.jpg
     
    34 GAZ and sloppy jalopies like this.
  17. Willywash
    Joined: Sep 18, 2019
    Posts: 100

    Willywash
    Member

    I am just wondering how many out there have built up their own Model A Frames.

    What kind of steel did you use ?

    How much did it cost ?

    How did you source the measurements, blue prints or from an original frame ?

    Did you build it stock style or with a stepped up rear ?

    Did you use a jig or rely on a level floor to get all the sections squared up ?
    Images below are for inspiration.
    View attachment 5413871 View attachment 5413872 View attachment 5413873



    I am including a couple of images for inspiration.[/QUOTE]
     
  18. Willywash
    Joined: Sep 18, 2019
    Posts: 100

    Willywash
    Member

    I used my original frame on my 31. Buying the boxing plates and the Speedway rear kick up and front cross member. The front cross lowered the car a inch or so. In the long run, time and money spent, I could have bought a new frame and chosen my ride height and set up custom built. I built mine on level floor of my shop, with lots of weights and measuring. What a pain! I might have have saved six or seven hundred bucks. But the car does ride and drive very well.
     
  19. lostone
    Joined: Oct 13, 2013
    Posts: 2,076

    lostone
    Member
    from kansas

    @chev34ute thank you for the kind words. I went with the commercial grille because it was plain steel, easy to chop 3" and Weld back together. At the time I didn't want to try and chop and Weld the original stainless steel grille shell.

    @Willywash just follow my link above, it will show you how I built the entire frame on a unlevel garage floor with no jigs, I show how easy it is to level a frame and Weld it together. Over 112" frame length totally flat and less than 3/16 on diamond on the frame.

    All the costs, procedures are there.

    .
     
  20. PotvinV8
    Joined: Mar 30, 2009
    Posts: 263

    PotvinV8
    Member

    Built this chassis from scratch for a '29 roadster. Used similar spec sheets as to what you posted, drew up some dimensions on the shop floor, and went to work. Built a jig from those dimensions, then got to work bending the tubing. I don't think this is exactly what you were looking for, but thought it'd be a good example of what can be done on the shop floor with a little hot rod ingenuity.

    IMG_0306.jpg
     
    alchemy, Fogger, X-cpe and 3 others like this.

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