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1924 touring car top bows
Posted: Fri Jan 21, 2022 9:22 pm
by Tmooreheadf
Are the top bows on a 1924 touring supposed to be flat or have a slight upward bow in the middle? The old ones are arched and the new ones purchased are flat. Just wondered which is correct?
Thanks
Re: 1924 touring car top bows
Posted: Sat Jan 22, 2022 6:39 am
by Humblej
I thought it was flat, but checking my original 1924 runabout top, it has a slight curve.
Re: 1924 touring car top bows
Posted: Sat Jan 22, 2022 9:51 pm
by Tmooreheadf
That’s about the same as my old ones but the new ones are as flat as can be!
Re: 1924 touring car top bows
Posted: Sun Jan 23, 2022 7:53 am
by Humblej
I would suggest throwing away the new flat ones and either reuse the old bows if sound, or make new ones that are correct. Many reproduction model T parts available today are made by reverse engineering or a best guess, and so some end up being just plain wrong. I have gone to the Benson Ford Research Center in Dearborn Michigan and made copies of the Ford factory drawings to make new wood for my 26 coupe. Sometimes a best guess isn't good enough. You have to ask yourself if 3/4" or so bow is necessary before you go to the time and expense of replacing the top on your car.
I have thought some beautifully restored cars had tops that didnt look quite right, almost a sunken appearance, and I must admit that until now I never really could put my finger on it. Now I know it is because the reproduction bows are flat.
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Re: 1924 touring car top bows
Posted: Sun Jan 23, 2022 8:08 am
by CudaMan
If your old bows can't be re-used, you could carve a thin shim with a bowed top and glue it to the top of your new bows to give them the rounded shape.
Re: 1924 touring car top bows
Posted: Sun Jan 23, 2022 11:49 am
by speedytinc
Are you sure they were not originally flat & the shrinking forces of the top material have created the slight bow??
A study of original/factory fotos may be in order before a conclusion is made.
Re: 1924 touring car top bows
Posted: Sun Jan 23, 2022 12:55 pm
by Humblej
John, I do not believe it is bending over time. The top material is not constrained along the sides of the top, only along the front and back of the top structure, therefore there is no side load applied to the bows from the top material. IF there was a shrinking force from the top material applied to the bows it would be along the top edge of the bows where the top is, and IF strong enough it would cause the bows to buckle away from the top material, not on the side of the top material, thereby causing the bows to sag, not crown. Looking at the condition of my original top, if there ever was a wrestling match between the bows and the top material, the top material would clearly loose, the material would stretch or split.
This is a bit of a tangential turn down a rabbit hole. Anyone with access to the Benson Ford can look this up, I will go again someday, but traveling to Dearborn is not in my immediate future.
These are the facts:
1 The question was asked by someone who has original crowned bows.
2 My original unrestored runabout top has crowned bows.
3 The repops are flat
With only those facts and without having seen the Ford factory drawings, I conclude they are crowned.
Re: 1924 touring car top bows
Posted: Sun Jan 23, 2022 5:04 pm
by speedytinc
Humblej wrote: ↑Sun Jan 23, 2022 12:55 pm
John, I do not believe it is bending over time. The top material is not constrained along the sides of the top, only along the front and back of the top structure, therefore there is no side load applied to the bows from the top material. IF there was a shrinking force from the top material applied to the bows it would be along the top edge of the bows where the top is, and IF strong enough it would cause the bows to buckle away from the top material, not on the side of the top material, thereby causing the bows to sag, not crown. Looking at the condition of my original top, if there ever was a wrestling match between the bows and the top material, the top material would clearly loose, the material would stretch or split.
This is a bit of a tangential turn down a rabbit hole. Anyone with access to the Benson Ford can look this up, I will go again someday, but traveling to Dearborn is not in my immediate future.
These are the facts:
1 The question was asked by someone who has original crowned bows.
2 My original unrestored runabout top has crowned bows.
3 The repops are flat
With only those facts and without having seen the Ford factory drawings, I conclude they are crowned.
I cant tell if you are screwing with me. Cant follow the logic, so I further investigate my own stuff.
First example: 2 years ago I cut up a bunch of 3/4" tack strip wood. Of the 8 remaining, they all have a "crown". 2 pieces have a double crown. (S shaped)
Second example: 23 touring 1 man top done 40 years ago with new repop(straight) bows. The 2 center bows have about a 3/4" crown. The back bow has a 1/4" reverse crown. I must have installed this one upside down?
I wonder if dimensionally the bows, at the top are wider than their mounting/pivot points & that creates a bend to the wood.
Re: 1924 touring car top bows
Posted: Sun Jan 23, 2022 6:43 pm
by Humblej
John, sorry if you think I am messing with you, I am not. I am stating what I know, and am avoiding making a best guess.
Re: 1924 touring car top bows
Posted: Sun Jan 23, 2022 6:48 pm
by speedytinc
Humblej wrote: ↑Sun Jan 23, 2022 6:43 pm
John, sorry if you think I am messing with you, I am not. I am stating what I know, and am avoiding making a best guess.
Ok. Sorry for my misunderstanding.
Maybe my observations of my 23 top fills in the blanks. Hope that helps.
Re: 1924 touring car top bows
Posted: Sun Jan 23, 2022 9:36 pm
by Tmooreheadf
I’ll be using the old bows as they are still good. The new ones are too big in both directions to go into the metal corner pockets. However the same supplier shipped the curved corner pieces and they fit perfect! Go figured!! Now to get everything riveted into place in the pockets. Bet that’s gonna take a while.