boxing plates
- Thread starter 1929
- Start date
Charlie Stephens
Well-known member
As others have suggested, find a new friend. Be sure to run a good background check on the new friend. If you box the frame (which is not necessary) you will be creating a Frankenstein monster that no one will love. The restorers will reject it because it has a boxed frame and a hot rod person will reject it because it has a Model A engine. You will either have to keep it forever or sell it at a loss. If you run ’35 wire wheels they can easily be changed back. If you box a frame there is no going back.
Charlie Stephens
Charlie Stephens
George Miller
Well-known member
Well you got good advice. But If you want to make a mess of it go for it.
Hoogah
Well-known member
1929 said:
Well, here they are (from the above posts)!
Bob Bidonde
Well-known member
If you box the frame, the stiffness changes and the stresses concentrate at places where the boxing plates end. This is basic physics.
Boxing is usually discontinuous at the cross-members, so where the cross-members attach to the side rails are places where the stresses will concentrate. How long the frame will last after boxing the rails I do not know. It's a complex fatigue life analysis. I suspect that the rivets attaching the cross-members to the side rails are the weakest link, so these should be checked often on a boxed frame.
Boxing the rails is old school. Today street rodders put the body on a new frame with modern suspension because boxing the frame was marginal at best.
Boxing is usually discontinuous at the cross-members, so where the cross-members attach to the side rails are places where the stresses will concentrate. How long the frame will last after boxing the rails I do not know. It's a complex fatigue life analysis. I suspect that the rivets attaching the cross-members to the side rails are the weakest link, so these should be checked often on a boxed frame.
Boxing the rails is old school. Today street rodders put the body on a new frame with modern suspension because boxing the frame was marginal at best.
Tom Wesenberg
Well-known member
If you are determined to do something to your frame, add stay rods, like train cars use.
I would make sure the frame is straight and do nothing more.
I would make sure the frame is straight and do nothing more.
I have a coupe that was reconstructed from parts - 1929 frame with 30-31 front crossmember, 1931 indented firewall body on 1930 fenders and running boards - go figure. The guy who put it together straightened the frame and welded in 1/4 inch steel plate on both frame rails just aft of the engine mounts to box and stiffen the frame. He had planned to drop in a V8 but never quite got there, so put back the Model A engine and drivetrain and drove it to work every day. He also installed 1940 Ford brakes with some more welding on the steel plate for a master cylinder mount.
The car rides and drives well but has a slightly different feel than a Model A. I think its the opposite of what happens when somebody puts in Float-A-Motor mounts, because some of the usual flexing of the frame is missing and so the ride is a bit stiffer. I see no advantage other than a frame that is not likley to sag in the midsection. The car looks very original from 10 feet away but, due to all the modifications, the value of the car will never approach that of an original Model-A.
The car rides and drives well but has a slightly different feel than a Model A. I think its the opposite of what happens when somebody puts in Float-A-Motor mounts, because some of the usual flexing of the frame is missing and so the ride is a bit stiffer. I see no advantage other than a frame that is not likley to sag in the midsection. The car looks very original from 10 feet away but, due to all the modifications, the value of the car will never approach that of an original Model-A.
Wolfes Metal Fab
New member
Im only responding to this post, as I was contacted and asked for my opinion and shown this thread, and asked to give my input. As a disclaimer, i do sell boxing plates, but i think you can see by my posts, i still give an honest opinion on if they are needed. Also, i do restore/streetrod cars on a daily basis, so my idea of easy or something being a problem or not, may be slightly different than someone who has never done it before, but then again, maybe not.
Quote:
Originally Posted by Kevin in NJ
Yes boxing the frame can make putting together a factory car with the same fasteners very difficult.
Not any more difficulty than restoring a building a car. Make a plan and find solutions to any problems during the planning period, not after the fact. This should not be a deciding factor for doing or not doing the boxing.
Quote:
Originally Posted by pooch
Yes, you have to have threaded slugs to take the original bolts, but it is not necessary on under 200 Hp.
For threaded slugs, regular nuts will work just fine and should be very easy and cheap to get. Just weld them in the needed places before boxing the frame. If you want to go further than this, you can get "Cage" Nuts that allow some movement of the thread, but hold it from turning. If you forget something that is not a critical suspension, motor, body, etc mount, then nutzerts will work, although not my first choice. This is also not enough of a problem to say don't do it.
Quote:
Originally Posted by Bob Bidonde
The Model A's frame was designed to be flexible, so it has just the right amount of torsional stiffness. Boxing the side rails will change the stiffness of the frame and concentrate stresses where they should not be. I strongly recommend that you do not do it.
If boxing the frame, why not box the whole thing? Then there is no drop off of stiffness for the stresses to concentrate at. You can also weld in the crossmembers to make it even stronger and more rigid yet. They were designed and made how they were, although since then, cars have been made with a much stronger frame that is less prone to flexing. Everybody has got an opinion on this one and each is probably different.
Is it absolutely necessary on a stock Model A, no. Is it a life or death choice one way or the other, no. It is an option and a choice. Would I do it on a stock model A, probably not, why, because i would be building a hotrod instead.
And i would definitely box the frame on it, probably with Dimples!
Here is an interesting link explaining an unboxed chassis having motor cranks breaking until they boxed the frame. Interesting!
http://www.hotrod.com/how-to/additional-how-to/0708rc-boxing-the-frame/
There are many others if you just google "boxing model a frame" and you can add in "stock" if you like. Then you can get many different peoples views and opinions to make your own decision, as i will not tell you you have to, or you shouldn't, but i will sell you the plates if you want to.
Brian Wolfe
Wolfes Metal Fabrication
Quote:
Originally Posted by Kevin in NJ
Yes boxing the frame can make putting together a factory car with the same fasteners very difficult.
Not any more difficulty than restoring a building a car. Make a plan and find solutions to any problems during the planning period, not after the fact. This should not be a deciding factor for doing or not doing the boxing.
Quote:
Originally Posted by pooch
Yes, you have to have threaded slugs to take the original bolts, but it is not necessary on under 200 Hp.
For threaded slugs, regular nuts will work just fine and should be very easy and cheap to get. Just weld them in the needed places before boxing the frame. If you want to go further than this, you can get "Cage" Nuts that allow some movement of the thread, but hold it from turning. If you forget something that is not a critical suspension, motor, body, etc mount, then nutzerts will work, although not my first choice. This is also not enough of a problem to say don't do it.
Quote:
Originally Posted by Bob Bidonde
The Model A's frame was designed to be flexible, so it has just the right amount of torsional stiffness. Boxing the side rails will change the stiffness of the frame and concentrate stresses where they should not be. I strongly recommend that you do not do it.
If boxing the frame, why not box the whole thing? Then there is no drop off of stiffness for the stresses to concentrate at. You can also weld in the crossmembers to make it even stronger and more rigid yet. They were designed and made how they were, although since then, cars have been made with a much stronger frame that is less prone to flexing. Everybody has got an opinion on this one and each is probably different.
Is it absolutely necessary on a stock Model A, no. Is it a life or death choice one way or the other, no. It is an option and a choice. Would I do it on a stock model A, probably not, why, because i would be building a hotrod instead.
And i would definitely box the frame on it, probably with Dimples!Here is an interesting link explaining an unboxed chassis having motor cranks breaking until they boxed the frame. Interesting!
http://www.hotrod.com/how-to/additional-how-to/0708rc-boxing-the-frame/
There are many others if you just google "boxing model a frame" and you can add in "stock" if you like. Then you can get many different peoples views and opinions to make your own decision, as i will not tell you you have to, or you shouldn't, but i will sell you the plates if you want to.
Brian Wolfe
Wolfes Metal Fabrication
pooch
Well-known member
Boxing plates alone do not do much, a K or X member does most of the work in reducing
torsional flex.
An X member is the best if you can shoehorn it in to a model A .
I have two rods with boxed chassis and on the second one I made a much stronger K member and it certainly shows on a rough road.
torsional flex.
An X member is the best if you can shoehorn it in to a model A .
I have two rods with boxed chassis and on the second one I made a much stronger K member and it certainly shows on a rough road.
Flathead
Well-known member
Well....these cars were designed by actual engineers who I doubt were idiots. They have been out in the world for 85 years give or take, driven hard on rough roads, been through tough years of the depression, neglected and abused. Amazingly there are quite a few left standing, but we should run out and box the frame rails because they aren't strong enough? I think not.
Tom Walker
Senior Member
In my opinion you will not improve the ride of your fairly stock car by boxing the frame.
Have you asked yourself exactly what you are trying to achieve?
Again, this is only my experience, but I think you would be better spending your time and cash by fitting panhard bars front and back.
Have you asked yourself exactly what you are trying to achieve?
Again, this is only my experience, but I think you would be better spending your time and cash by fitting panhard bars front and back.
hardtimes
Well-known member
Hey Brian,
Thanks for your lucid /thoughtful input.
1929,
If you are going to use that original 4 banger A/B engine, even warmed up , you should just make sure that the frame is straight, IMO and experience. Ford and others left the Model A frame behind when going to MORE power and beefed up their stock frames more/more as power was added.
War story !
Many decades ago, I had a '31 Model A roadster with a full house 265 cu in. Chevy engine with 2 four barrel AFBs. Frame not boxed at all. I'm basically a putter/driver and I loved how that roadster drove/rode. It also had chev three speed and rear end. It would flex hard under power, so I drove it gently 99% of the time , so that it would last...and it did last !
Only time that I ever remember using the progressive linkage and the second AFB was to 'dust off' some clown in a Plum Crazy colored car with a giant wing on the rear and a paper dealer plate on it...yeah, he asked /begged for it
!
The A frame held up real well ....unboxed, at least till I traded it off for a 1955 corvette. Your choice, have fun, eh
Thanks for your lucid /thoughtful input.
1929,
If you are going to use that original 4 banger A/B engine, even warmed up , you should just make sure that the frame is straight, IMO and experience. Ford and others left the Model A frame behind when going to MORE power and beefed up their stock frames more/more as power was added.
War story
!Many decades ago, I had a '31 Model A roadster with a full house 265 cu in. Chevy engine with 2 four barrel AFBs. Frame not boxed at all. I'm basically a putter/driver and I loved how that roadster drove/rode. It also had chev three speed and rear end. It would flex hard under power, so I drove it gently 99% of the time , so that it would last...and it did last !
Only time that I ever remember using the progressive linkage and the second AFB was to 'dust off' some clown in a Plum Crazy colored car with a giant wing on the rear and a paper dealer plate on it...yeah, he asked /begged for it
!The A frame held up real well ....unboxed, at least till I traded it off for a 1955 corvette. Your choice, have fun, eh
George Miller
Well-known member
If it is great shape after 85 years and it is going to a Model A engine, why do you want to box it You do know that if you box all the frame, your rear motor mounts will not fit, your steering gear will not fit. Don,t forget to weld all the nuts to the frame that you cannot reach after the boxing is added.
Yes I have boxed a few hot rod Model A frames over the years, good luck.
MikeK
Well-known member
Modification is not restoration. Call it what it is. Another one bites the dust.