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Fiat 806: research and scratchbuilds


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There are some minor corrections regarding our photo 3 as well . What I consider as most important is the top-line of the fairing where we can see the sheet wrapped around the wire and the radiator case without the background " buttons "

Many greetings !  Hannes

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Hello to all,

back again at home, I have got the reply of Paul Kierstein about the stops around the vertical steering arm:

 

Dear Olivier:

Thanks for sending these. I have not noticed such stops on the cars here but to be honest I have not looked very closely. I will take a quick walk to see what can be found. I did do that and found that most of the cars here (road and track) have the steering gear hidden under the hood.

Attached is the gear from the Bugatti 35B. I will keep a look out. My guess is that the steering box would have some kind of internal stop to keep the gears from going too far.

The best

Paul 

 

tcwpvJ.jpg

 

jdqPPF.jpg

 

If we can't see such stops on the Bugatti, these photos are anyway interesting. Here is an enlargement of the 2nd one:

KSks5X.png

 

Sorry, this has probably been said above in the thread, but what is this thin wire running along the frame? we have nearly the same on the 806.

Many thanks to Paul, credits from the Rev's institute.

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Very interesting photos . Many thanks , dear Paul Kierstein ! It´s interesting to see how the arm which connects the steering case with the drop-link is mounted onto a support .

For our car the 7 mm steel plate should be sufficient as a support  but I ask myself  if it was connected by bolts or similar .

Regarding the thread : In my opinion these rivets and bolts needed to get secured for safety reasons . This way they cannot hit the car or the driver  behind during a race if they get loose .  Another  purpose is to hold the bolts in place by preventing rotations .

Many greetings !  Hannes

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Thanks Hannes. I have asked Paul about the purpose of this thread, maybe he will confirm your suggestion.

 

K5tBpr.png

 

Waiting for more infos on the subject, I made this enlargement to show this same thread on the 806. It seems to begin at the front part of the frame reinforcement and to stop on the 2 nd eyebolt (imho, the thread goes through a little hole in the eyebolt).

Notice on the same enlargement the brake cable, braided: the 0,38 mm suggested by Robin was definitely a very good choice!

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This wide enlargement shows I was wrong thinking the thread was running inside an eyebolt. It seems more surely go around each "bolt":

PEMiDL.jpg

Furthermore, notice that, on the 806, it seems to run lower than on the Bug: we can see the thread "under" the frame.

P.S: Fred, Thierry, do you know what is this thread made for?

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Dear Hannes,

I have received the 0,2 mm Albion nickel silver rod you recommended to make the spring, but this material is not soft enough for such a purpose. After several trials, I have chosen 0,3 mm Multirex tin wire, wrapped around a 0,38 mm steel rod (0,4 mm Aber). The tin foil must be tightened, as on photos 2 and 3. This is very easy to do with tin wire. The disadvantage of tin wire is that it is fragile and may break if you don't take care.

I am glad of the result, my spring is 1 mm diameter, exactly what I wanted (the kit's one is 1,42 mm, nearly 45% thicker).

The lenght of the spring is difficult to determine precisely, because it connects the leaf wearing the up hook behind the exhaust, but 14,5 mm seems to me quite probable.

On the photo below, the spring is a bit too long, I have reduced it after the photo. One more time, take care when handling the tin wire. But if you fail, you just have to do it again, what needs not more than 5 mn with this material...

ObTTMy.jpg

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Dear Olivier , your spring looks very convincing ! You could use the same method for the springs around your spokes !

In the meantime I made plans how to get the skeleton of the rear axle to it´s correct horizontal situation , because I want to connect it with the bottom panel  by a strong sheet . 

I needed some time for deliberations and finally found a solution . I´ll show some pics when my construction is done .

I also removed both " sheets " below the engine mounting points and will replace it on the right side by a real sheet with brackets . My radiator case was altered as well .

Many greetings !   Hannes

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4 minutes ago, Hannes said:

your spring looks very convincing ! You could use the same method for the springs around your spokes !

 

Thanks Hannes! Indeed, I will use the same method but with 0,12 mm copper wire wrapping the 0,4 mm spoke, which will require me to remove some spokes... The truth is for this price...

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Pity, despite the HQ of this photo 2, it is nearly impossible to say if the mounting point for the spring was a hook or an eyebolt. We can see however that, contrary to what we thought, this point is on the chassis and not inside. From this point of view, let's admit that the kit was finally not so far from truth. So, I had to remove the little rings I had ever glued inside.

I have personally chosen the eyebolt option, that seems to me more probable, because more secure than a hook. The spring would be so permanently fixed to the chassis, while the mechanic would pull on it by the up hook  handle to close firmly the bonnet.

 

b6zEcg.png

 

For my eyebolt, I have chosen one from Knupfer. Of course, only its head will be used, and before cutting the thread, I have reduced by filing the head.

 

ZE4Y8s.jpg

 

One of my 4 eyebolts in place. It is maybe a bit too big, but it is acceptable

nggzEo.jpg

 

 

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We have seen (see my post of last august 17) that the long steering arm (16B in the kit) is in fact a tube. I had to order a 2,5 mm tube, not easy to find. On PB modélisme, I found an alu one (inside diameter 2,1 mm). I will rework that part of my build:

- replace my steering connector (28B in the kit), still too short 

- replace my 2,5 mm steering arm rod, using the alu tube ordered

- move backward the horizontal rod (17B in the kit) in order my front spring to come between this rod and the radiator case.

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36 minutes ago, Hannes said:

I already bought an 2 mm alu tube by Knupfer and it is quite stable .. The inner diameter is ,1.1 mm  , but I can widen both ends by drilling a bit .    Hannes

Dear Hannes,

2 mm diameter is imho too thin for this steering arm. I have got the one from Albion Alloys (alu) but I didn't use it because of that.

P.S: A.A does not purpose a 2,5 mm alu tube, only 2 or 3 mm

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I have redone my button (3rd time) and this time, I am glad of the result. I used a completely different method, using a 2,5 mm brass rod, that I filed in cone shape. On it, I glued a little portion of 0,7 mm A.A tube (on which my spring hook will  dock) and, on this last one, a 1 mm diameter tin foil rivet (instead of 1,2 previously). In the same time, I have leveled a bit the fairing too convex in this area.

 

SerUMZ.jpg

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Difficult to post after Nick's eclipse. We are just poor humans trying to do nice things, but the Nature is a so amazing artist... Just look at a nice flower closely...

That said, as mentioned above, the weights will be represented by kinds of tiny springs, made by wrapping a 0,12 mm copper wire around 3 spokes/ wheel (the weights don't have the same lenght). I had to remove the spokes from my rear right wheel. I will paint them before recementing the spokes. One more time, I doubt anyone did that before on a 806 build. 

For lack of offering the show of the moon hiding the sun, we try to be the first ones to "walk on it!" (other wink to Tintin ;))

frAhIW.jpg

 

I prefer to do one wheel after the other. I have applied a coat of Vallejo 950 (black) on the coils. Just have to wait them to dry and they will be replaced on the rear right wheel. The same procedure will be applied for the 4 wheels.

MMcVla.jpg

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I have just got Paul's reply about the thin thread running on the Bugatti (and the 806, see above):

 

Dear Olivier:

This is safety wire to prevent the bolts from turning and becoming loose. Apparently this was a big problem from the rough roads on the Targa Florio. The collection car here was driven by Chiron in the 1935 race. Note the bolt head construction. Bugatti was famous for having propriety fastners even to a odd screw pitch for the threads.

 

The best 

 

Paul

 

Very interesting reply, thanks again Paul! So, the 806 bolts were probably different from the Bugatti's...

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Chaps,

 

One thing I've been struggling with is aligning the new version  of photo 2 with my model.Eventually compared old to new. The new is stretched by 2.356% in the vertical direction. Not sure which is the right version. I got reasonable alignment across a number of photos using the old version but I am includined to believe the newer version. Higher resolution should imply an earlier generation of the picture so closer to truth. I'll need to have a bit of a play to work out which is closer to correct. in the meantime a small amount of caution is required.


Nick

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2 hours ago, Olivier de St Raph said:

I have just got Paul's reply about the thin thread running on the Bugatti (and the 806, see above):

 

Dear Olivier:

This is safety wire to prevent the bolts from turning and becoming loose. Apparently this was a big problem from the rough roads on the Targa Florio. The collection car here was driven by Chiron in the 1935 race. Note the bolt head construction. Bugatti was famous for having propriety fastners even to a odd screw pitch for the threads.

 

The best 

 

Paul

 

Very interesting reply, thanks again Paul! So, the 806 bolts were probably different from the Bugatti's...

The type of bolts has nothing to do ... These cars were subjected to strong vibrations, which regularly unclamp all nuts and bolts!
Dan.

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