Mercedes Benz 300 SLR n° 722 - Overall winner 1955 Mille Miglia, driven by Sir Stirling Moss - FINISHED

[Toftdale]

Very elegant solution to the steering - Andy 

[CrazyCrank]

Thanks for the kind comment @Toftdale and @Spiny

 

Well, solution adopted.

 

I've designed, inspiring  me from Mercedes Benz Ref photos,  a steering box, which is currently 3D printing. Because of very thin details, I've decided to print it with layers of 0,01 mm, and it  will take more than 3 hours.
Not sure the proportions are good , but once printed, I could see wether it fits at its place or not, and wether it looks oversized or not.

 

The drawing (without pretense, I don't have the skills of @nick, to name but one )

 

 

The rendering:

 

  

 

  

 

See you later with the printed parts

 

 

 

 

[Fnick]

That is looking very good Thierry. So useful being able to make your own parts!

 

Nick

[CrazyCrank]

Morning gentlemen

 

The 3D print failed because, I think, too thin supports and possibly incorrect orientation of the model.
I've modified that in my slicer and the second 3D print is on the way.
The proportions seem good at first glance.

 

Wait 1h20 and see

 

 

 

[Jo NZ]

1 hour ago, CrazyCrank said:

 

Wait 1h20 and see

 

we've all been there.... hope it works!

 

 

[JeroenS]

Fantastic detailing job Thierry! Very good work.

[CrazyCrank]

 

It worked  😎, but.....🤨 !

 

The genuine part (Copyright Mercedes Public Archives)

 

 

My interprétation:

 

Bottom of the part, which It needs still to be sanded:

 

 

Top of the part:

 

.  

 

Right side view:

 

 

 

Left side view:

 

 

Front view

 

 

 

The test fitting seemed good:

 

  

 

  

 

 

 

But once the front drums put on the chassis, it appeared the the steering box is oversized a bit, its right side come,g almost in contact with the left drum, not allowing to place the rear brass left hose of the upper water cooling line !

 

 

 

So, the 3D print has to be redone, decreasing the size of the part from about 30%

Not a big deal, just about 80 minutes 😎

 

 

See you soon...

 

 

 

 

 

 

 

[Pouln]

Good try and sure good you tested the fit. Next one will be fine, I’m sure

[CrazyCrank]

1 hour ago, Pouln said:

Good try and sure good you tested the fit. Next one will be fine, I’m sure

 

Yes, Poul, it is ! 😎

 

The new part mesures about 4x4x4 mm, no photos needed, it's the little clone of the first one.

 

So it was time to get down to business:

 

1/ I've  enhanced the kit's part on which is glued the steering box, and on which will be fixed later on the suspension triangles, and the shock absorbers.  I call it a "stand"

 

Indeed, its top part was wrong on the left: there was only a small relief, when they are 2 on the real thing. Moreover the more internal relief is in reality a curious part I don't know how to describe.

 

 

So, I sawed off 2 slots with my jeweler's saw to simulate it, and glued a 1mm section of 1xx mm squared styrene rod.

 

 

2/ Then you can see that the radiator does not float on the front of the chassis.

 

It is held in position by two bars, each of which attaches to a curved part of the tubular chassis, not shown on the kit chassis, and which itself attaches, at the front, to the chassis rail and, at the rear, to the "stand" I mentioned earlier.
So I made the curved uprights, with a 1 mm styrene rod, shaped them little by little during many blank tests, then glued them on the stand. They will only be glued to the frame rails when the time comes. And of course I also made, with a 0.5 mm brass tube, flattened at the radiator end, the bars that will be glued on the curved uprights.

 

Several photos are more explicit than a good speech:

 

 

 

  

 

3/  I've made and re-made several time the tests fitting, between the new steering box and its stand, on the chassis, with and without the front axle and drums , with the upper water cooling  line, etc...
And I noticed, as you can see on the pictures below, that all went well together, and that the only issue I had to fix is that the left brass tubes of the water cooling line are slightly too short and have a slightly too open angle.
This is easy to fix, as the tubes aren't glued, and I can make new ones.

 

 

Time to relax now, with painting job of these elements, and next, I'll finish the assembly of the brass steering bar I showed you yesterday

 

To be continued 😉

[Fastcat]

Hi CC,

            Nice work on all the 3D stuff. Shouldn't be necessary really, even allowing for the age of the kit but I can't see us getting anything better soon.

Other items I don't think Revell included were the two cans just before the exhaust pipes. I think these were expansion boxes and I seem to remember that either they were lacking in detail or missed off completely. It didn't really matter as kitted because the panel in front of the exhausts was moulded in place, but on the Mille Miglia car, this was removed. I think it was an access panel for the mechanics to get at the spark plugs so it was left off for speed of service but I'm sure it would have helped cooling too. Just the job for printing!

 

Dave

[CrazyCrank]

Evening guys

 

As promised, I've painted the parts I improved yesterday, easy job.

 

I think it's not very visible on the pictures below, sorry for the bad quality, but the stand has been painted dark steel,  the curved struts semi-gloss black, and the steering box aluminium, and the retaining bars of the radiators painted aluminium.

 

  

 

 

Really nothing very interesting to see !

 

As promised too, I went on modifying the steering system, and, while I was there, I took the opportunity to modify as well the suspension triangles and their attachment to the wheel spindles.

 

Indeed, during a test run I noticed that the 2 pins, at the top and bottom of each spindle, that are supposed to fit into a suspension triangle, to maintain a semblance of cohesion in the whole, on one hand won't be very solid (what I already noticed with the same system on the MB 300 SL from Tamiya), so there's a risk of disassociation later if the glue dots don't work, and on the other hand, because the aspect could be greatly improved to make it more realistic.

So I used the same principle as for the steering bar:
- we cut the pins.
- We drill a 1.0 mm hole in the place, and we'll put two 1.0 mm bolts, which will go through the hole dedicated to the pins on the steering triangles, at the top and at the bottom
- Problem: the pins I'm going to cut are 1.6 mm, like the hole for them on the steering triangle.
- I don't have 1.5 bolts, I have 1.6, a bit big, with a too disproportionate head, that's why I chose 1.0 mm bolts that are more realistic and that I have in stock.
- So that the system, once mounted, would not be loose, I had to reduce the size of the 1.6 mm hole on the steering triangles, the ones supplied as a part in the kit, for the top, as well as the ones incorporated (how silly!) in the tubular chassis.
- I found in my stash some 2.3 mm outer, 1.2 inner plastic tube, which will fit the bill perfectly.
- I reduced the outside diameter on the lathe for a small length, to just under 2.0 mm and cut 45 sections of 1.75 mm long.
- I located the 1.6 holes of the 2.0 mm triangles, and inserted in my 4 holes a 2.0 mm tube section, glued with Tamiya super-fluid.

 

The rest was a hoot to do, I'll show you some pictures

 

  

 

  

 

  

 

It remained to paint the upper and lower triangles and spindles in a very light steel colour (A mix 50/50 between Alclad Stainless steel and Alclad White aluminium) and later, I'll burnish my micro-screws (I'm not going to leave them brass ! ) and I'll  electro-plate "nickel" the steering bar

 

  

 

That's all for now, guys, I've spent a lot of time today taking care of my grand-daughter Emma, who caught a cold and couldn't go to school ! Family first !

 

Stay tuned if you like

 

 

[silver911]

Great work...even better to hear your just as good at being a Grandad

Family first and last...and everything in between mate.

 

Ron

[CrazyCrank]

10 minutes ago, silver911 said:

Great work...even better to hear your just as good at being a Grandad

Family first and last...and everything in between mate.

 

Ron

 

I know, Ron, than you and me share the same feelings

Thanks a lot again  for your kind words

Thierry

[CrazyCrank]

1 hour ago, Fastcat said:

Hi CC,

            Nice work on all the 3D stuff. Shouldn't be necessary really, even allowing for the age of the kit but I can't see us getting anything better soon.

Other items I don't think Revell included were the two cans just before the exhaust pipes. I think these were expansion boxes and I seem to remember that either they were lacking in detail or missed off completely. It didn't really matter as kitted because the panel in front of the exhausts was moulded in place, but on the Mille Miglia car, this was removed. I think it was an access panel for the mechanics to get at the spark plugs so it was left off for speed of service but I'm sure it would have helped cooling too. Just the job for printing!

 

Dave

 

Thanks for the kind comment, Dave, really appreciated, coming from you  

 

I don't understand what you are talking about with these cans, as I don't have any documents or photos of the real model or of the various reduced scale reproductions that have been made where you can see this type of element.
Can you be more precise, @Fastcat or, if you have a photo, put it in a post, to enlighten me?

 

As far as the planned improvements are concerned, it remains:

- The modification of the exhaust line of the kit, after the manifolds
- The battery
- The two spare wheels in the boot
- The modified fuel tank of course
- The primary fuel pump in the trunk, as well as another cylindrical tank in the trunk (part of the braking system?)
- The gearbox control linkage
- The modification or "de novo" manufacture of the steering shaft
- The fabrication of new suspension elements, those supplied in the kit being rough and inaccurate
- 3D drawing and printing of 6 new spoked rims
- The replacement of the 4-spoke steering wheel by a 3-spoke one, also in 3D printing, or scratched with a part of the kit steering wheel...
- The addition of the master cylinder of braking system
- And probably many others I forgot ...

 

Thanks in advance for your answer....

 

 

[Fastcat]

Hi CC,

                    Have a look at : link   If you also look at CMC's model of the engine, you should see it as they've modelled it. They're the large cylindrical pieces that join the two sections of exhaust pipe together ie the chrome end pipes to the natural metal pipes from the engine. You can see them through the access panel aperture

 

Dave 

Edited May 5, 2022 by Fastcat
My age and failing memory

[CrazyCrank]

50 minutes ago, Fastcat said:

Hi CC,

                    Have a look at : link   If you also look at CMC's model of the engine, you should see it as they've modelled it. They're the large cylindrical pieces that join the two sections of exhaust pipe together ie the chrome end pipes to the natural metal pipes from the engine. You can see them through the access panel aperture

 

Dave 

Oh, that !

I believed you spoke of another part of the car !

 

These cylindrical central parts of exhaust lines, are molded on the kit parts but only for the visible section. I mean, they appear as a cylinder cut in 2 along its length !

And are inaccurate because undersized  in diameter !

 

  

 

Of course I'm going to modify that. I wrote it in my previous post, at the top of the list of things I've planned to improve !

 

 

[CrazyCrank]

Morning mates

 

To go on with the exhaust line modification which @Fastcat talked about, which I has already planned, but wanted to make later:

 

The cylindrical "can" after the exhaust pipes is not accurate and incomplete as you can see by yourself
its diameter on the kit part is 4.6 mm and I think, after comparison with ref. photos, that 5.2 is needed

My plan is:

- cutting  off this cylindrical part of each set of 4 pipes

- drilling a 1.0 mm hole on the exhaust line

- Inserting in the hole a 1.0 mm brass pin

- Fabricating a new 5.2 mm cylindrical part

 - Connecting it to the exhaust set via the 1.0 mm pin

- And inserting in each cylindrical part the chromed end of each line

 

First, the cylindrical part:

Initially I planed to make it on the lathe. But, as we can see on ref. photos, there is on this cylindrical part, on its rear face where join the chromed pipe, some triangular fins, 3 imho.

 

 

And these fins will be impossible to make on the lathe, and difficult for me at least with a milling machine.

So, I've drawn them with Fusion 360 (not perfectly close to the real but resembling enough), and they will be 3D printed soon

 

  

 

Second: It will remain to fabricate the metal fastening in the form of a double collar, with a thin strip of aluminium.

 

Third: I don't know yet wether I'll use the kit's chromed ends of the exhaust line, because they are inaccurate . Indeed they have a conical profile, when the real thing is a true cylinder !.

So, it highly probable that I'll scratch new ones.

 

I do love my 3D printer

 

Stay connected if you like 😎

 

[CrazyCrank]

Evening guys

 

Going on taking care of my grand-daughter, I've however been able today to progress a bit with non-time consuming tasks

 

First, I've nickel-plated the brass  transmission bar I scratched a few days ago:

 

All imperfections are shown by the magnification, what a shame !

Fortunately, with the naked eye, mine at least, it isn't visible !

 

  

 

Second, the suspension triangles and wheel spindles have been cleaned, primed, painted light steel and semi-gloss varnished

 

 

Third, I've remade the brass lines that come out the left side of the upper water-cooling line

Using bras tubes, but 0.6 mm one, to be closer of the real. And the rubber sleeves at both end of each one, have been made with a short section of a 0.8 mm / 0.6 mm diameter brass tube, that I've threaded on the 0.6 one's ends !

This give a better relief than painting them only.

They have been primes and painted, alu and Tamiya Rubber black

It remains to protect them from handling before adding the "Cerflex collars"

 

 

Fourth, I've burnished the brass hardware I'll use to articulate the steering bar and the wheels spindles, and have secured them in a little plastic bag

 

 

And fifth, while my grand-daughter took her nap, I've made a more interesting job, in order to improve more if possible the front and rear axles:

 

Indeed, the parts supplied in the kit to represent the front and shock absorbers are frankly inaccurate and to say the truth, very bad !

 

Here is what Revell did: front shock absorber on the left an rear on the right

 

  

 

I took inspiration of ref. photos:

 

  

 

And drawn new parts with Fusion 360:

Here the difficulty is we have to take in account that the fixation system provided by Revell doesn't allow the slightest error, in terms of length of the parts, and in terms of spacing between fixing holes or pins.

🙄So, it took more time than expected, and countless checks with a digital caliper.

 

Front one:

 

  

 

  

 

Rear one:

 

  

 

 

At the moment, I've obviously planned a 3D printing tonight, and hopefully, all that stuff could come out nicely.

If applicable, some corrections will be done on the drawings and a new print needed.

 

That said, the work progresses well, and, once the exhaust lines assembled, tested on the engine, and the whole set checked on the chassis, if all comme together, I'll be able to going on the engine, with finishing of the distribution, scratching of the 8 fuel lines etc. before definitive fixation of the engine on the chassis

 

Stay connected for next (mis)adventures 🙄

 

 

[Steben]

Incredible.... 🤩

Simply incredible.
What detail and what a focus

What printer do you use?

[CrazyCrank]

9 minutes ago, Steben said:

Incredible.... 🤩

Simply incredible.
What detail and what a focus

What printer do you use?

 

Thanks Steben for your kind comment

I use an Elegy Mars 1 Pro, with ABS like resin

 

[CrazyCrank]

All the stuff is sliced and ready for 3h04 3D printing.

I cross my fingers and pray the Modellers's God 🙏

 

 

I'll see you tomorrow when they get out of the bath

 

[CrazyCrank]

Evening guys: )

 

Have been very busy all the day, and because of an Internet outage in my neighbourhood, I couldn't post on my thread to show you the progress.

But, now it works, so, let's go for a loooooonnng post 

 

The rear and front shock absorbers came out nicely, as well as the exhaust cans, but for those last ones, I made a mistake drawing them, so, although they are really nice, they are not usable for my goal.

 

I've slightly modified the drawings and the second bath is the good one.

 

And, as I had drawn too yesterday 2 new parts, I've 3D printed them with the new exhaust cans:

 

 

What are these 2 other parts that you can see of the picture above ?

They are 2 missing parts that I've planned to use to scratch a more realistic steering shaft.

 

Hereunder is the nicely detailed kit's part:

 

 

Hereunder a Ref. photo (Thanks Mercedes Benz  )

 

 

I've so decided to scratch a steering bar,  using:

- a 1.5 mm brass rod, which will be nickel plated

- A new front end part, this kind of "ring" or "crown" as said my grand-daughter Emma

- A rear addition, the ribber bellows

 

My drawings :

 

  

 

  

 

The results of all my 3D prints since 24 hours:

 

Front shock absorbers:

 

  

 

Rear shock absorbers

 

  

 

Rubber bellows for the steering shaft:

 

 

New connecting crown for the steering shaft:

 

 

New exhaust cans:

 

Sans titre by Thierry Decorniquet, sur Flickr

 

Sans titre by Thierry Decorniquet, sur Flickr

 

And you could see that it's interesting printing several examples of the same part because sometimes, some of them have defects

 

So there is a lot of work to do now on the bench:

 

Before fixing the engine on the chassis, several operations must be done, in a precise order/
The first of them is to fix definitely the exhaust system on the engine block.
And to do that, we have to make first a blank test with the bodywork on the chassis , because the chromed exhaust pipes come out of the right side of the body through two apertures, and their exact position can't be determined before, the fitting seeming very tricky (while reading the assembly instructions).

Especially since I modified the diameter of the exhaust boxes, and I have to add the flanges to fix them !

 

So, I had to go on with the exhaust system:

 

Must I use this ? (the kits's parts, on their sprue, one of them inserted in a new exhaust can)

 

 

Or this ?

 

 

YES, I took my metal lathe out of the dust, after almost 1 year without touching it...  what a pleasure ! 

I had forgotten how much fun it was to tease metal with this tool!

 

So I've turned two new exhaust ends in a brass rod, more realistic and accurate than the plastic parts supplied in the kit.

For instance, the thickness of the tube wall is, at the very end, about 0.15 mm, which is enormous (3.6 mm at 1:1 scale) but looks really good at the naked eye

Moreover, the thickness of the wall will seem lower when the interior of the tubes is painted smoke black

 

  

 

Isn't this mostly preferable ?:

 

 

I have chosen to simplify the system, even if the result will be slightly inaccurate, because it will not be visible or only slightly.
My brass tailpipes are both 12 mm (plus 4 mm of insert)
In reality, the top tube is longer than the bottom one, because the top exhaust box is located further forward than the bottom one, and the manufacturer wanted, for aesthetic reasons I guess, that the two ends of the tailpipes on the right side of the car look the same length.
But on the kit, from memory, when you superimpose the 2 sets of 4 exhaust pipes, the exhaust cans appear superimposed at the same level and not offset:
Also the top can is more slanted upwards than the bottom one which is almost horizontal, and MB has welded the top chrome exhaust to the can so that it is parallel to the bottom one, as in the photo below.

 

 

Of course, the exhaust brass ends and the rod I'll used to scratch the steering shaft will be nickel plated

 

 

It's time now to cut off the plastic exhaust cans, make the blank tests, and then scratching the exhaust can collars and painting.... tomorrow probably 😎

 

[CrazyCrank]

Good morning happy modelers

 

I've cut off the plastic "cans" of the exhaust lines, made a blank test on the engine and noticed that, contrary to hat I thought aid wrote yesterday, the 2 cans are also offset from each other, the top one being about 1.5 mm further forwerd.

 

SO, I've turned a new bottom brass exhaust end, whose dimension is 1.5 mm shorter, so 10.5 mm.

 

I've nickel plated the chrome exhaust and the steering shaft, and this is the result I got:

 

( Don't take worry about one of the cans, which lost its fins during handling, they serve only for tests, and I've made 12 ! )

 

  

 

   

 

  

 

  

 

My iPhone 13 camera, decidedly merciless, shown me that the upper chrome exhaust is not nickeled enough on the front section.

So, I'm going to improve that, even if it wouldn't be visible, since I'm going to "flame" the exhausts to blueing them, as on the real !

 

On the other hand, you can notice the thinness of the chrome exhaust wall at its end  👍

 

 

And for the steering shaft, it remains to paint the rubber bellows and the coupling crown:

 

  

 

Things are progressing well 😎

 

Stay tuned if you like

 

[CrazyCrank]

Once painted, the rubber bellows and the coupling crown look far better and I'm happy to see on the real tiny crow all the details I drawn in Fusion: bolts and holes especially

 

  

 

 

The crown has been gloss cleared, and in 24 hours, after full drying, I could assemble the 3 parts...and it will be done for the steering shaft (will just remain to adjust its length I've made excessive, to handle it easily during nickel plating )

 

Now, blank tests with exhausts on the engine, engine on the chassis:

 

  

 

 

And blank test bodywork on the chassis with engine and exhausts:

 

 

Not bad imho 😉

 

Let's go now for scratching the "double collar" which joins the exhaust "cans", not an easy task if we want to be accurate and not out of scale 🙄

[Toftdale]

The exhaust tips look fantastic,  far superior to any kit supplied item - Andy