Roger Zimmermann

Construction of a Continental Mark II model, scale 1:12

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On ‎11‎/‎15‎/‎2019 at 9:35 AM, Fadt said:

Roger.

1/8th wire wheel which I made for a hot rod model. If I can do this, you should be able to do it will ease. Spokes were 12 thousands of an inch. Had to make a rotary milling table to do the rim and hub holes. Used Gerald Wingraves book as a reference and information on how to do it, but did modify his method to my way of doing things.

 

 

Thanks Gerry for the picture. I'm not quite sure if I understood the spoke dimension: 0.012"? At scale 1:8, that's 2.4mm; almost like a spoke from a bicycle! Mines are more stable: 7mm; I will use brass rods of .6mm (0.024").

I have also the books from Gerald; however his method is not suitable for my needs. You will see my method soon!

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Benefits of AACA Membership.

Sorry, I meant 20 thou. Used brass wire not rod.

 

The spokes on my full sized hot rod are 3.8 mm and they were chosen as they are thicker than normal for this kind of wheel.

 

1204426164_13(2)(2015_11_1311_07_31UTC)(Copy).thumb.jpg.287f979eada174d3e2e54326ed79cf5b.jpg

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As you may understand, I began to do parts some time ago. I did not publish the beginning here because I wanted to finish the Avanti report first. Now, I can relate what I did up to yesterday.

 

I'm switching between the dash work from my '72 Cadillac Coupe de Ville and now the construction from that scale model. The 4 hubs are done and I began the drums. All four are the same which is a simplification. As usual, I'm working with brass, a so super material on a small lathe! The raw slice has a weight of 120 grams; the finished drum has a weight of 14 grams! They would be perfect candidates for casting, unfortunately, I'm not able to do that.

The first drum is almost finished: I must add 8 reinforcement ribs; they will be done when the other 3 drums are born.
 
A few days later:
 
The 4 drums are ready (minus the 8 ribs which will be added later) and attached temporarily with the hubs. The hubs themselves are far from ready; an original assembly is also shown.
I began with the wheel's hubs, a difficult task. Those parts are stamped steel, I have to do them on the lathe with multiple operations and tool changes. The rear inner side from the first hub is ready; some work with hand held chisel is required which can be dangerous as you may imagine.

2 inside drum.JPG

3 drum.JPG

4 Drums ready.JPG

5 Carving the hub.JPG

Rear drum.JPG

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The rear part of the hub for the six wheels is done. To help to understand what I'm trying to replicate, I'm adding a picture from a real wheel. Now, I will begin to machine the hub's front.
To facilitate the manufacturing, I'm doing on each part the same group of operations. I just hope that I will not have bad surprises!

6 Wheel hubs.JPG

IMG_0844.JPG

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Sometimes it's good to wait to perform some task. While the drums were in work, I wanted to do the 8 (!) holes per wheel for the studs. I'm now glad I did them not.
While I began to machine the first wheel hub at the front, I had to modify some dimensions. With the calculated bolt circle, it would have been very difficult to "torque" the nuts because they would be very near from the hub's outer diameter. Therefore, I reduced a tad the bold circle and, instead of the 1.2 mm studs, I will use smaller ones: 1 mm. With eight per wheel, the risk to loose a wheel is reduced!
I also enlarged the aperture for the hub cap by 1 mm to have a better access to the wheel nuts.
If you are looking at the attached picture and older ones, you will notice that I'm using now a 4-jaws chuck. I had to do the change because with the original one (which is well worn), I could not have a piece turning true.

A few days after:

The wheel hubs were machined inside; to work the outside, I had to make a special tool. The hubs will be attached with the studs to the tool and then the work at the outside will be possible. This may be abstract for the moment; you will understand when I can show the process. The first picture is the tool almost ready.
On that picture, you can see that I'm machining a cone. I suppose that the wire wheels were rather flexible and unstable; the hub with the bearings has the same cone (not so wide) and the wheel hub is resting on that cone to enhance the stability. I attempted to reproduce this characteristic, however, for the usage of the model, this extra work is more a futility than a real need. 

As I had to do the threaded holes into te tool, I used the opportunity to use the setting of the drilling machine to drill the needed holes into the drums and wheel hubs. There were a lot of holes: 6 wheel hubs @ 8 holes, 4 drums @ 8 holes and the special tool also with 8 holes!
The reduced bolt circle is exactly what I expected; I will have room into the wheel hubs to "torque" the nuts attaching the wheels.

7 Working the hub.JPG

8 Tool for the hubs.JPG

9 Drilling the hub.JPG

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Still using the lathe...I'm adding the picture showing the drum's drilling. When this was done, I began to machine the wheel hubs. Now, you can see for what the special tool is used; the lathe was not turning when I took the picture because the tool must be hold with both hands. The last picture is showing an almost finished wheel hub. Why "almost"? Because there are 40 holes for the spokes which must be drilled.
I began each wheel hub using a bit of brass weighting 80 grams. The finished part has a weight of 6 grams! I cannot say that it's very economical!

 

After I finished the wheel hubs, I saw that I did a mistake at the drums. When the wheel is installed on the drum, the wheel hub is going into a recess from the drum, with a small gap between hub and drum. The gap I had was way out of line. What to do? redo again 4 drums? No. I cut a band of brass, shaped it like a ring and soldered on the drum. On the attached picture, the joint can be seen; once paint will be applied, this misshapen will not be seen. The fin is on the right, ready to be soldered.
I milled 8 slots into the drum to help for the location of the reinforcement fins. I realized then that those fins are very small and difficult to held for soldering. Therefore, for the next parts, I did the fins much longer and milled a fracture groove. The tail is a help to handle the part during doing it and to held the fins during soldering. Once soldered, the tail can be broken away. I now have just 30 to do!

10 drilling the drum.JPG

11 machining a wheel hub.JPG

12 completed wheel hub.JPG

13 drum and fins.JPG

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The drums are now ready; I had almost more time to do the fins and solder them to the drums as turning the drums themselves (but with lass waste!). The hubs are now attached to the drums; it will allow me to continue the details on the hubs; an original one can be seen somewhere on this page.

 

If November is the season's end for old cars driving, it's now the good season for modelling! The original hubs are made with cast iron; as I cannot cast parts, I have to machine them to try to give the same aspect; this is what I began. The first picture is showing the hub in work with a dentist mill. The second picture is showing a finished hub. Indeed, I could spare this work because once the wheel is installed, the hub cannot be seen!

14 drums.JPG

15 machining the hub.JPG

16 Drum and hub ready.JPG

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With the drums, hubs and wheel hubs ready, the logical continuation is the rims. By accident, I discovered  that the original wheel I had during my stay in Germany was most probably from a V-12 car (18" for the V-16 and 17" for the V-12). By making comparisons with the excellent drawing in the shop manual, I saw that the proportions are not right. Further, by substracting from the nominal wheel diameter the exterior rim diameter, I came to an absurd thickness for the sheetmetal. Suddenly, my wheels have an increased diameter of 2mm (a difference of 1" is giving 2 mm at this scale)! By chance, I did the verification before all was finished!
This discrepancy is explaining why I had a too large pocket diameter at the drum: the wheel hubs are also different! No, I will not do 6 new wheel hubs, nobody will notice that error.
In my material, I found a "tube" made with brass. I will have to take away some material (the tube has a weight of 1.1kg); I had to close one end to be able to reduce the outside diameter. This is what you can see on the first picture.
That huge piece of brass is totally disproportioned compared to the lathe!
If you are good looking at the last picture, you can see metal chips near the cutting tool: this small machine has an automatic advance which I very seldom use; after I cleaned the old grease, I could let it do the work. Between each cut, I must let cool the machine...

17 For the rims.JPG

18 oversize stock.JPG

19 in work.JPG

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That huge tube is now over. When the outside diameter was OK for me (it's larger then necessary, it will be turned down when I'm doing the rims), I did deep grooves into the cylinder. As my tool is not allowing to go deep enough, I went further with a hand tool and finish the job with a saw blade, one by one.
Now I have 6 rims to machine, will be busy for some time!
The reason about the smaller diameter for the wheel hubs is now known: the frame I measured and took pictures is from 1933; the wheels are 17" and not 18" like 1932. Thanks Johan (from Cadillac Club) for the explanation!

 

The rims are in work. As the shape is what it is, there is a lot of work. One is almost ready; the second one is in work. One side is ready, I have to do the other one by using a different chuck to grab the part at its outside diameter.

 

The remaining 5 rims are machined on one side. On the picture, the machined side is shown on 3 rims, the other ones are "upside down" to show what I have to do on all rims.
Recently, I ordered brass rods to make the spokes. Then the real fun will begin!

20 pre-cut.JPG

21 deeping the groove.JPG

22 future rims.JPG

23 rim in work.JPG

24 Almost done.JPG

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What a lot to take in, with your posts today - I am still totally amazed at this modelling work you do.

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Thanks Mike! Sorry if it's was too much. The today reports in fact are describing what I did in more than one month. As you can imagine, I need less strength to change the chuck from my lathe compared to yours!

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The last report from today. Now I have to go to work!

 

A few days ago, I began to machine the other side of the rims, hoping that my calculation was correct and that enough metal is still there!
Apparently, all went well. The zone where the spokes will be installed at the rim is rather thin, maybe .5mm or less. As my caliper is too wide for the central groove, I had to rely on the sketch I did.
The second picture is showing how the rim is machined with a hand tool.
The problem to machine the other side of the rim was to have as concentric as possible; I hate when machined parts are turning like eggs! For that, some imagination is required; this time a bit of paper was needed to have both sides turning true (third picture).
Now, the rims are done, the wheel hubs are done, the spokes must go in! Well, before I'm drilling both parts with 40 holes each, I have to make a jig to install the spokes. From a scale model forum I got a good idea which I modified for my needs.
Basically, the rim is held on the jig with 3 clamps and guided bat the inside diameter of the rim. The wheel hub is attached in the center with 4 bolts and positioned by the central hole from the hub.
The next step: drilling the holes for the spokes at the rims (rather easy) and at the hubs which will be more difficult because the holes are not perpendicular to the surface. How many drills will be broken until I'm finding the right way to drill?

25 machining the other side.JPG

26 hand work.JPG

27 a trick with paper.JPG

28 jig.JPG

29 Hub & rim.JPG

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The rims are drilled without problem, but it was the easy part because the holes are perpendicular to the surface. I predrill anyway all the holes with a stronger drill and did the holes with a more flexible drill; it's more work but the safe way.
The next will be a lot of fun as the angles are compounded.

30 drilling the rim.JPG

31 drilling the rim.JPG

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On 11/16/2019 at 10:28 AM, Roger Zimmermann said:

Thanks Mike! Sorry if it's was too much. The today reports in fact are describing what I did in more than one month. As you can imagine, I need less strength to change the chuck from my lathe compared to yours!

 

It's never too much !  😉

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Thanks Paulie and John!

 

As I anticipated, drilling the wheel hubs was not as easy as the same operation for the rims. I used one afternoon to evaluate the correct angles and for the set-up of the machine. As there are angles on both axis, I had to imagine how I could get the second one without too much trouble: a rigid piece of cardboard was put at the back of the drilling press, used as a reference line; with that, I could put the arm at the angle I wanted with another piece of carboard as a guide. As the holes are a bit larger than the spokes, a 100% precision is not needed.
As you can see from the pictures, the holes are drilled at a daunting angle. To avoid drilling waste, each hole is done in 3 steps: first a tiny milling cutter diameter 0.5mm is used to have a flat surface for the next step. Then, a pre-hole is done with a rigid drill diameter 0.7mm (installed on 2 pictures) and finally the hole diameter 0.6mm is done with a flexible drill. If I had the same type of drill for the final hole as I'm using for the step #2, I could spare one operation. On the other side, the larger pre-hole is allowing some movement for the spokes during the installation.
I had some trouble with the second set of holes at the back of the hub. As the machine is too small, I had to do another set-up and I saw that I'm doing the second set of holes at the same direction as for the first set. I could correct the error before it was too late.
I'm still not sure if I will be able to drill the holes on the small diameter of the hubs as the angles are quite different but the machine still the same size...

32 drilling the hub.JPG

33 drilling the hub.JPG

34 drilling the hub.JPG

35 drilling the hub.JPG

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All the holes into the hubs are done; I'm glad it's over! After the first row at the large diameter, I had to drill the second row which holes, if I'm right, are between the holes from the other row. The difficulty was to find the right spot to drill; unfortunately, there are some differences between the hubs. Maybe this will not be evident at the first glance.
The next task was to drill the holes at the smaller diameter from the hub. As the spoke’s geometry is different than the one for the rear spokes, the angle at which the holes must be drilled is more challenging than for the rear.
I began with the row situated near the end of the hub. By looking at the shop manual’s drawing, it was obvious that the holes cannot be drilled completely through the metal because they would be outside the surface covered by the hubcap. On the other side, this is almost a benefit: I must not solder the spokes at this location, only at the rim.
The second row at the smaller diameter from the hub is also specific; the holes are very near from the ones from the outside row.
The various pictures are showing how I had to deal with my small machine; for one operation, I had to leave the bead from the machine alone to avoid an interference with the electric motor.
About the motor: lately, it had a lot to do; while drilling the outside rows, it began to act like there was not enough fuel! In fact, one of the brushes was worn and did no more contact the commutator. Fortunately, I had one on stock and could replace it to finish the drilling. I could be a good idea to order another set…
Finally, all the drills are still in good condition, nothing broke!

 

Now, the real fun will begin with the spokes.

36 drilling the hub.JPG

37 drilling the hub.JPG

38 drilling the hub.JPG

39 drilling the hub.JPG

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The first wheel is done!
At first, I thought that the spokes having an elbow would simplify the construction. Well, not exactly: the spokes must be at the right length because when the elbow is going through the hole at the rim, the spoke must be almost at the appropriate hole at the hub. Well, it took a long time for the first one; now I have recorded the length from the 4 different spokes, this will simplify the assembly for the next wheels.
It seems that my device to hold hub and rim was a good design: the finished wheel is turning perfectly true!

40 The first wheel.JPG

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Wow!!!!    What a beautiful wheel. I can't get a full size wheel to look that good.

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Thanks Alex! The full size wheels are also looking good (your pictures helped also) and they are certainly done with more precision!

I have now a problem: if I'm painting drums and wheels the same color (don't ask which one, I don't know yet), the details will be lost. Maybe was it a possibility to paint the wheels a different color as the drums/frame? For example, a blue frame, blue drums but yellow wheels, was that possible? (it does not means I will choose this color combinaison).

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Roger

According to the authenticity manual for 1932-33, “After the frame and chassis were assembled (excluding the engine, splash pans and transmission) the entire unit was painted black. Then for custom cars the standard black chassis could be painted over to the customers color specifications. For the 1932 Cadillac and possibly other years painting over the standard black with colors was a standard option”.

 

Below is the standard paint schedule for 1932. From what I understand other colors can be had per customer request. This information is from the authenticity manual.

 

 

926965772_paintschedule.thumb.jpg.88214aa379572bd652646f707dd4f8e1.jpg

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Thanks for this interesting information. One thing is sure: the model's frame will not be black and according to the table above, it was possible, even from the factory, to have the wheels a different color than the frame. Anyway, I'm not that far, the frame must still wait  some time!

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