I'm getting ready to box a Model A frame for a 2 door sedan. My question is: --Can it be "Trussed" rather than boxed and has anyone done it? Some manufacturing companies make boxing plates with large holes along the entire length. Wouldn't diagonal truss plates or bars maybe 1 1/2" be just as strong?
You can... just have to be cautious of warp. The one nice thing about boxing plates (holes or no holes) is that you can work with a long section at a time, tacking at several locations... adding strength against twist as you go. But always take it slow and weld randomly around to disperse the heat (especially if you don't have a jig/table). I've always researched and asked myself "there must be a reason why so many do it this way, rather than that way"... since i'm not an engineer... Best of luck!
I like boxing over most other options because it keeps the road **** out of the frame and is easy to stay clean. Your proposal sounds like a lot more messing around for no gain...
There was a post on here earlier about combining both.I will post up pics tonight when I get home from work.Done that way,it should be as strong and rigid as anything I've ever seen.Planning to use this method on my blown Hemi A project. Scott Posted using the Full Custom H.A.M.B. App!
Here is what I was referring to....he has welded the bracing to both the original frame first,then the boxing plates by cutting small notches for weld penetration.He was pretty sharp to come up with this,but I can't recall which HAMB member he was. If anybody knows who this was,please speak up so he can receive credit for this. Posted using the Full Custom H.A.M.B. App!
This looks like a great idea. Might not have to use the "trusses" all around, just from the driver's side from the front crossmenmber to the second crossmember. (Lots of stress from modified steering systems motor mounts etc.)
Maybe with the 700+ hp supercharged,stroked,early Hemi and violent hydroStick transmission I'm planning to put into what is a relatively flimsy,brittle,80 yr old model A frame...? How can it possibly hurt anything to make the frame stronger,more rigid,more resistant to twisting and damage,and also more able to handle the near 1000lbs of static weight that is a blown Hemi/Hydro combination...? Posted using the Full Custom H.A.M.B. App!
with that sort of power, a set of molly tubes fab'd up to emulate the look of an a frame might be smarter... your mileage may vary
Those pics above look not only like ****, but it looks like its just adding a **** ton of weight that is totally unnecessary. Just get some boxing plates, put them over the ch***is, leave a 1mm gap and weld them in so if you want to sand them off you still have good peno, otherwise tig weld them and just paint over it. Boxing a frame and adding a K or X member will make it stiff enough.
I boxed mine last week, starting at the back working towards the front. I noticed that while I was working forward the box plate didnt line up at the top of the rail which I ***umed was a fatigue from years past. So I used a clamp and drew the box plate up and tacked it off. I thought it was just me till I tried the opposite frame rail and it was the same damn way.
I agree that his welds are pretty knobby looking at the rear of the frame.If properly welded and the welds ground down,you wouldn't even see the work.....especially since there will be a car sitting on top of most of it. As far as the weight issue,I am constantly finding ways to cut weight from the car,because it's like free horsepower;although for the roughly 20-30 lbs of flat stock,and maybe 10lbs of welding rod needed,I don't think weight is going to be a big deal....An interior can easily add the 30-50lbs that Im guessing this might add. Not saying its the answer for every situation,just saying its got me interested in trying it out.I think between this,and a well fabbed x-member,and the vintage style cage Im planning for my coupe,it should be able to handle anything I can throw at it without flinching. Posted using the Full Custom H.A.M.B. App!
I think the pics above show the best way possable to get max strength out of the stock A frame. I have thought of running a length of 1 1/2 or 2' box 1/8 wall inside before boxing, but I also like this idea.
That's a great idea that would be less labour intensive...just s***ch it in,and drill a few holes in your boxing plate to weld it to the square tube as well,then grind flat.I'm thinking that might be the way to go.... Posted using the Full Custom H.A.M.B. App!
Man all that bracing and stuff looks like a lot of work - and a lot of welding to add heat/cool stresses. Straight boxed frame is plenty strong enough as once you have 4 sides those inner braces won't actually be doing anything. Those braces will add strength if the side plate wasn't being used. But you have to ask about what all that welding is doing to the frame? Wouldn't just be easier to get a factory custom made frame (SVF; Kiwi; Speedway etc) that's been done in a factory jig etc?
Just my opinion based on owning one: a really well boxed A-frame is still flimsy in terms of maintaining shape along it's horizontal plane. An 8-point cage is a wise addition to keep the doors from flying open when you press the loud pedal.....or hit a bump.
It does look like a lot of extra work. There's probably SOME benefit to it, but it'd take some software modeling to figure out where. Personally, I think boxing it then filling the rails with Terocore would probably help at least as much...just make sure you're done with all the welding first.
At the risk of sounding like I live under a rock,what is terrocore...?Like expanding foam? I'm pretty sure I've heard it mentioned before,but I have no experience with it. Posted using the Full Custom H.A.M.B. App!
It would be easier to just buy one,but I always hate buying stuff that I could fab myself. It always leaves me feeling better to know that I have created something from nothing,AND saved money to use on another part of the car... Posted using the Full Custom H.A.M.B. App!
I wouldn't be a fan of trussing an entire frame, however on this Model A, I boxed the entire frame, with the exception of the steering box area, which I trussed. I was concerned about strength in that area, with a window for the steering box to fit. After these shots were taken, I boxed right up to the flatbar and plug welded to the flatbar as well.
Terocore is a very very bad idea. The foam will collect and hold moisture. You can't get paint inside those rails. Moisture on bare metal..... Do I need to continue? It works on modern cars for a couple of reasons. Most modern cars are dipped in an E-Coat. This stands for Epoxy coat. Once that is done they will shoot in the foam (Terocore). This takes place in area's that will not see any moisture. Not inside uncoated frame rails.
Hi Marty, What was your reasoning behind the lengths and angles of the trusses you installed?I notice they seem to be very specific lengths,with angles at odd locations.Was there a specific reason you made them like this,or were you using up some s**** ends of flat stock that just happened to be those lengths,so you arranged them to fit? I have always had concerns about the steering box area as well.I see you put some flat stock on top of the frame at that point as well.I have seen old frames done that way as well,and the ones I saw lasted pretty well. What kind of power was that car making,just as a point of reference? Scott
Scott, I started with the heavy bar on the inside top, because (2) of the bolts mounting the steering box go through the top of the frame rail. I then weaved the flatbar to fit top to bottom. The pics don't show it, but I skip welded the whole thing inside, as well as fully welding it along the bottom. The boxing I added closed the gap around the steering box. With the plug welds (boxing plates to truss), it made it nice and strong. It is only running a mild flathead.
Well for one thing, you won't be able to run any electrical, brake, or gas lines inside the frame. I boxed mine the full length. Holes are drilled at body mounting points (channeled) for access. Holes are drilled from cowl forward mostly for looks. Also added 1-1/2"x1" tube k-member. If you are doing it in your garage without a frame table or jig, here is what I did. Support frame on jack stands making sure its level. I then welded 1-12" angle from one side to the other. The spacing between angles was just enough to lay on a big block chevy head to hold the frame down and keep it from warping. Put big block head on each end. Use prudent welding practice and good luck.
It also just looks more...."right" when the frame isn't a perfectly smooth,die-stamped,modern looking piece.I personally like a little bit of "grit" on a hot rod....not scabby workmanship,just good old backyard engineering like guys used to do back in the day when they were making this **** up as they go. Hell,my Grandfather used to lower customs for young guys on a budget by heating the rear springs with a torch,then having a couple volunteers sit on the trunk until the ride height was "adjusted" to where the owner liked it!Now that there is some ultra low tech ****.....and TOTALLY straying from the original topic of this thread.Haha! Sorry about that.Lack of sleep makes me a bit ranty.... Scott Posted using the Full Custom H.A.M.B. App!
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