Roger Zimmermann

Nice kitchen! And good job on the pistons. You were both lucky to have not be burnt with your experiment!

Cars from this time were rather simple: many parts, pure mechanical devices. Probably not all were so carefully build like Cadillacs were: for example, the lever I pictured recently was installed with a needle bearing on the brake shield. Probably cheaper cars would just have a bronze bushing for the same configuration. The solutions retained were rather logical but to reproduce them on a scale model is another matter. As an example: I began to reproduce the large lever you can see at the right on the picture of the original assembly. It has a strange shape, but it was very ingenious: the nut at one end was used to finely adjust the brake shoes. This nut pulled or pushed a rod connected to the splined hub, modifying the position of the hub in relation to the lever. As my project is to make a rolling frame, many details will be seen. Therefore, I had to reproduce the splined shaft & hub. I will not add the provision to adjust the brakes, because this detail would ad too much complexity at this scale. The question was: how to do the splines? By chance, I had a milling cutter with the appropriate width. I imagined that I could do a shaft in brass and broach a piece of brass 1.5mm thick. To my satisfaction, the splined shaft was good looking. With a pilot hub, I entered the shaft into the hole of a scrap piece of brass, put the assembly in the wise and put pressure. I saw small bits of brass and was thinking that life is good, the tool is making its way. When the shaft was through, I pushed it back and, to my dismay, I saw that the teeth were just shaved! Obviously, my solution was not good. I reluctantly took a piece of mild steel and did the splines on that shaft. Contrary to my fear, the milling cutter had no trouble to work on that mild steel. Another hole, another test: still no good: the teeth were still there, but pushed back, creating a bulge. Not good for a part which should have a snug fitting! I came to the conclusion that broaching can only be done with a tempered steel shaft. My milling cutter will be instantly destroyed if I make an single attempt! Another brain storming was needed. By chance, I have a large stock of dentist milling tools; the shaft's diameter was near to the desired shaft diameter! I removed from that milling tool what was not needed and, with a diamond covered disc, I made an approximate splined shaft which was to be used as a first pass. The definitive splined shaft would then finish the female splines. This time, the whole process was a success. With the tempered shaft, I could do the approximate broaching; the final treatment was done with the shaft which will be used on the model. There is an inconvenient with this method: shaft and lever must be indexed and will not be interchangeable as my machining is not precise enough. This add a bit to the complexity, but as there are only 4 shaft and lever pairs, it can be done. And, fortunately, the parts are the same for the front and rear brakes. On the pictures, that lever is just an approximative shape. I wanted first to be sure of the broaching process before doing the final shape. Probably Mike will also appreciate: one day to make the tool and 10 minutes to broach the four parts!

Recently, I added a small shaft for a brake lever at the front brake shields as well as the insert for the bolt limiting the steering angle. One challenge was to drill a 0.4mm for the cotter pin. It's good to practice now because there are a lot of cotter pins on that frame! Then, I began the lever which will be actuated by a cable. I'm adding a picture showing the set-up for the front wheels; the picture is from a restored 1932 V-8 brake shield assembly, which is almost identical to the V-16 one. To replicate cast parts is taking a lot of time; I was aware of it! As I cannot cast small or large parts, I have to do them differently. The second picture is showing the lever and limiting bolt from the RH brake shield, + the parts which are constituting that lever: a shaft, 3 "bearings". The smaller ones are drilled entirely, the large one only up to the middle. The assembly is done with soft solder. After that, the final holes for the various pins/shaft are drilled. Finally, the width of the assembly will be corrected; to facilitate the construction, the "bearings" are larger (or longer if you like).

Probably the method to pull the bushing was not ideal: the piston is a cast part; the surface on which the special tool rested is not 100% perpendicular to the axle. I would imagine a device to guide the bushing using the free hole from the piston and the inside diameter from the bushing. With that, even if the tool is not perfectly perpendicular, the bushing will not be canted. If you can guide the bushing the right way into the piston, you will probably be able to save it as the shaving was not on the whole surface.

During our short vacation in France, I took the raw material which will be the pattern to shape the frame and I began to work on it. It's 5mm thick, therefore, I cannot prepare it at home, I have no suitable vise. That piece of brass is 420 mm long or 16.6" Back home, I'm continuing the brake shields by adding the various element to make the brakes operable.

It will be definitively have a better fit and finish as when it left the factory! Very nice work.

Then, I could be able to help you more than with your present project!

Take care of your health! Glad you are feeling better.

Happy New Year to all! The end of 2019 was not kind with my front brake shields, I will relate it later. First I'm showing the various steps to shape the second brake shield. I prepared a piece of brass large enough; drilled some small holes to prevent too much damage, first picture. After 1/3 stroke, I checked how the metal is taking its new shape; no problem to report; this is the second picture. At 2/3 of the stroke, the metal is already torn at one end (third picture). Dies builder is a profession; probably there is a method to avoid the issue (choice of metal, various steps, etc.). Once completely pressed, the damage is obvious, but smaller than with the first shield, fourth picture. A patch will be silver soldered anyway. I began then to trim the center, to make the needed space for the knuckle. The first problem I encountered was with the shape of the recess at the top: I did the corner's cuts at 45° and I could not put the knuckle high enough! By looking at the pictures I have, I saw that the corners are at about 25 to 30°. I modified both dies to the new shape and I tried to rework the shields by pressing them again. No problem, the brass was soft enough to accept the new shape. Then, I could finish the aperture for the knuckle. I put a drum on the "assembly" (the shield being just pushed on the knuckle) to note that the drum is resting on the brake shield! What to do to get those 0.5mm interference away? Well, the first step was to modify the ears on which the shields are attached by removing 0.25mm. More was not advisable because they were 0.7mm thick. Then, I modify the dies once more by carving the recess by an additional 0.2mm. Here again, I got no protest from the shields and no damage. The third step I will do is to modify the inside of the drums to have just enough clearance. I assembled a brake shield on a knuckle (fifth picture); I still have a slight interference; the drums modification will get rid of that. While I was with the camera, I redid a picture showing how the flange are shaped with a small hammer; this is the last picture.

Thanks Paulie! I'm using 0.3mm half hard brass (0.012"). I annealed the rear ones; I tried the first front one without heat. I annealed the brass just to finish the shield and, of course to silver solder the repair.

After the rear brake shields were ready, it was time to modify the dies to press the front shields. At first, I was thinking that the shape is easy; well it was the case to do the separate male insert. The female job was not that easy. The almost rectangular cavity could be milled, but the half round one was more difficult to get. Milling was not an option, at least not with my basic machine. I removed almost all the metal with grinding and finished it with a hand tool, shaving the brass until the insert was flush with the flat surface. The male insert was then attached to the other die with a screw. Then came the moment of truth: will the brass be torn as the cavity is rather deep? Nothing bad happened at mid way, but at the end it was torn at the end of the cavity. To repair it, I cut the damaged spot, pressed a bit brass, adjusted and silver soldered it. This repair took much more time than pressing the shield! Now, I have to do the second one; most probably the same damage will occur; then I can show with a picture or two what I intended to explain.

Interesting story...Anyway, you certainly had no trouble to travel with that light vehicle on the trailer, especially traveling so many miles. We had more difficulties when my '72 de Ville was transported from the customs in Zurich to Bienne (about 100 miles) because the car was a tad too far back, plus the weight from the spare parts in the trunk! At more than 40 MPH, the trailer began to dance...

That's a good explanation, thanks!

I'm wondering if the black paint from the fenders was an inferior quality as the body; could be that the body had a repaint but the fenders not?

Thanks for explanation! I suppose that, due to the modest power and speed from that vehicle, 8 peened rivets are sufficient!

Which material is the center, cast iron? After the rivets are in, is there some welding process?

I'm wondering how they did that. When I built the Mark II scale model, I went many times to the guy who had 3 or 4 Mark II. The people at Danbury had probably a method I'm not aware of it.

Thanks John. Happy New Year! What could I do next? Rather logically, the brake shields should logically be next because they are attached to the knuckles. But now, I'm doing the rear ones! Too much red wine lately? No! the reason is that the rear shields are rather simple and the front ones are more complex. The outside diameter is the same, that's all. The dies I did are modified dies used for the Mark II wheel covers. Once the real shields ready, those dies will be modified to do the front ones, sparing that way a lot of material. The dies are on the first picture. The second one is showing my method to press the brass with the dies. I was glad to see that the first shield went out without problem; the surface had some waves which could be almost eliminated by rubbing the high spots with a hammer. Unfortunately, the second shield developed a crack as you can see on the next picture. Doing another one is not a guarantee of success, therefore, I repaired the crack by silver soldering a piece of brass inserted into the crack. The next operation was to shape the outer flange; unfortunately this picture is no good but both shields were already finished as shown on the last picture (only one was pictured). The flange is shaped with a hammer on the die as making another tool just for that was a waste of resources. A small hammer can do wonders! Later, these shields will be adjusted on the rear axle; the 6 attaching holes drilled, plus a number of parts for the brakes will be added. I just can say that mechanical brakes are very complex, compared to the hydraulic ones. The bonus: I may have the brakes functional on all 4 wheels.

The last examples are used in the 1956-63 Hydramatic transmissions. The Spirolox have a small rectangular aperture at the ends to facilitate their removal with a small flat screwdriver. The diameter used in transmissions is rather large; I don't know if they would be suitable for a gudgeon pin. The ordinary stamped ring with ears are used on the input shaft at the fluid coupling. The external snap rings with a square section are used on the output shaft; a specific tool is needed to remove or install them. Sometimes I have to fight a long time to get them away because the tool is slipping...