So on my '25 T sports racer "adding lightness" was the theme. It was a very lightweight car. When I started on my "modified", I wasn't going to do that again, but the brackets just looked too plain and boring. So I started drilling holes again. Once you start, you can't stop halfway through. I sold that frame and all the brackets that went with it.
So I've started my roadster. I am using an original '28 Ford frame. I modified the front crossmember, putting the spring in front of the axle. This lowers the car about 4" from stock. I am using a Chrysler 251 straight 6 flathead engine. Its huge and bloody heavy. "adding lightness" would be pointless. So with this build I'm trying to make the car look like it was built in the pre-war era, 1939 or 1942, depending on which side of the atlantic you were on. In that timeframe there were no hot rod magazines and very few speed shops or manufacturers. The junk yard was your parts store. With that in mind, I'm going to try making all my brackets (that dreaded word) look like they came off a factory built car. Usually they were stamped or forged. So that's what I'm trying to mimic. So I started picking up various crossmembers and looking at my leftovers stash.
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The Model A frame I'm using is a very simple ladder frame. 2 frame rails and 3 crossmembers. This used a 4 cylinder engine. The straight 6 I'm using is a lot longer, so the middle crossmember has to be moved further back in the rails. The rails aren't parallel, so as the crossmember goes back, it needs to get wider. So I removed the crossmember from the frame and set about widening it. Luckily I had some scraps of another crossmember. I also needed to raise the hump in the middle. The hump was also asymetric, and as I'm going to be adding legs to the crossmember, that was taken into consideration as well. So trying to make it look like a factory part made it into a jigsaw puzzle! It's just tacked at the moment, but once fully welded and cleaned up, I think it will achieve my goal.
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With that modified, I turned to the transmission cradle. The finished car will sit very high by modern standards. The engine and transmission sit very low in the frame. I didn't want a bulky cradle that would be in full view. Back to my stash. I thought about how a factory would make it. Looking at my stash, I decided to use a Model A front crossmember and some other bits. A factory would have stamped this. So corners would be soft radius. First job was to remove most of the sides of the crossmember and then straighten it out. Pie cuts were made to do this.
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I was then able to make a sort of "W" shape. It also needed to be wider in cross section to be able to bolt under the middle crossmember. The raised flat portion was for the radiator. I cut another off another butchered crossmember. Everything was held together with clamps and angle to keep the surfaces level. The missing bits were filled in using parts of a Model T frame. All these bits are .166" so the thickness is consistent, and the radius is the same. Before welding I grind a deep bevel on the edges that is filled by the weld puddle, so when I flatten the weld I'm not weakening the joint. I also ground a shallow bevel on the back side and welded that too.
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So that's where I'm up to. Got the other end of the crossmember to do next.
Cheers,
Stewart.