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KEMNA street roller in scale 1:22.5

Started by fspg2, April 07, 2018, 12:15:28 AM

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With the roller it goes on only slowly.  

Two inner cover panels were merely milled from 3.0mm brass.

Kemna_Walze-Gigant-8_319 (fspg2)

Kemna_Walze-Gigant_8_267 (fspg2)

Slowly, the first printed small parts come in:

Kemna_Walze-Gigant-8_320 (fspg2)

Kemna_Walze-Gigant_8_157 (fspg2)

When comparing the last two pictures I noticed a mistake on my part ...grrr......

Well, the handle sits exactly on the opposite side - has happened.

Kemna_Walze-Gigant-8_324 (fspg2)

Kemna_Walze-Gigant-8_321 (fspg2)

Kemna_Walze-Gigant-8_322 (fspg2)

Kemna_Walze-Gigant-8_323 (fspg2)

Given this, and especially since I need two of these handwheels, I have again invested € 14.40 / per wheel for two raw brass lost-wax parts.

All parts I have previously ordered as raw came gold-shiny therefore free of extra charge.
The steps of the often quite coarse resolution (see the oblique connection on the small casting on picture 320) are usually not visible ... but the parts themselves are a little bit smaller - for example: the wheel diameter should be 17.8 mm ...

Kemna_Walze-Gigant-8_325 (fspg2)

...it has 17.45mm to 17.54mm - about 1.5% - 2.0% less.

According to information from another printer provider, the shrinkage behavior in lost wax casting is negligible.
Soon I will have a comparison, if I get from there new parts.

After 10 days I got the new handwheels.

Kemna_Walze-Gigant-8_333 (fspg2)

left: sandblasted new wheel, the levels of printing are no longer visible to the naked eye. To keep the wheel during sandblasting with the big gloves better, I have tied it to a 0.3mm wire.
middle: the unfinished second part
right: the old hand wheel with the toggle in the wrong position.

The rear "coupling u-pile" is also ready for installation:

Kemna_Walze-Gigant-8_332 (fspg2)

Kemna_Walze-Gigant_8_155 (fspg2)

For the numbers "1, 0, 2, 3" on the lever rack I used the font type "ROMAN D". Although "bold" has been activated, the four numbers appear extremely thin.

Kemna_Walze-Gigant-8_326 (fspg2)

Kemna_Walze-Gigant-8_327 (fspg2)

Kemna_Walze-Gigant-8_328 (fspg2)

Kemna_Walze-Gigant-8_329 (fspg2)

Kemna_Walze-Gigant-8_330 (fspg2)

Kemna_Walze-Gigant-8_331 (fspg2)

Volker helped with modified letters.

The result is a broader appearance of the only 0.9mm high numbers.

Kemna_Walze-Gigant-8_334 (fspg2)

on the left the original font - on the right the new modification.

Kemna_Walze-Gigant-8_335 (fspg2)

In a few days I will get the part in brass from wax-lost casting.

Kemna_Walze-Gigant-8_336 (fspg2)

Yesterday something strange came to light!

Kemna_Walze-Gigant-8_337 (fspg2)

...shit happens... :-)

It almost looks as if my router wanted to try as a 3D sausage printer.

It should be milled out from a 2.0mm brass plate only the bottom plate below the checker plates!

Kemna_Walze-Gigant_8_160 (fspg2)

Kemna_Walze-Gigant_8_161 (fspg2)

Kemna_Walze-Gigant-8_339 (fspg2)

Kemna_Walze-Gigant-8_340 (fspg2)

At second try it worked.

Kemna_Walze-Gigant-8_341 (fspg2)



Slow, steady, world class modeling. -- Russ

Ray Dunakin

Quote from: finescalerr on August 25, 2018, 11:08:02 AM
Slow, steady, world class modeling. -- Russ

What Russ said!

Did you find out why the router went haywire?

Visit my website to see pics of the rugged and rocky In-ko-pah Railroad!

Ray Dunakin's World


Incorrectly, I used a 1.2mm drill instead of a 1.2mm cutter. I only noticed it when the drill broke off.

I had drawn the coupling plank 0.6mm longer to counteract shrinkage during 3D printing.

It fits :)

Kemna_Walze-Gigant-8_343 (fspg2)

Kemna_Walze-Gigant-8_344 (fspg2)

Kemna_Walze-Gigant-8_345 (fspg2)

Kemna_Walze-Gigant-8_346 (fspg2)



I want to make the middle hood area of the roller foldable - like the prototype.

Montage_Blechhaube_Kemna_01 (fspg2)

My first idea was to solder an 1.2mm tube to the 0.2mm side panels and then clamp them into a jig, to mill the mutual gaps.

Here is the fear that the only 2.0mm long and 1.2mm in diameter tubes do not join the movement too long.
Also, the brazing of the thin parts is certainly not really accomplish, without that the sheet burns up or rejects.

So Volkers attempt was a little more convincing as he visited me recently.

On the web, I found two examples very similar - only much smaller: click and click.

Kemna_Haube_beweglich_01 (fspg2)

Kemna_Walze-Gigant-8_354 (fspg2)

Kemna_Walze-Gigant-8_353 (fspg2)

Meanwhile, a colleague at Buntbahn forum gave a good hint!
He asked if it would not have been easier at the prototype to weld something like a piano band under the sheets.

I had only a few partial views of the hinge from the Kemna Roller in Herborn.
After I had assembled them in Photoshop and downscaled to 800px for the forum, although I could count the number of hinge sections ... only accurate details were not really recognizable on the piebald surface.

So I have inspected the original images again, and lo and behold ....

The side parts had been riveted to the hinges.

Kemna_Walze-Gigant_8_358 (fspg2)

Kemna_Walze-Gigant_8_359 (fspg2)

Kemna_Walze-Gigant_8_360 (fspg2)

At the Buntbahnforum Henner showed his way to make hinges. Contribution from 2011/11/24: click.

Far more difficult will be the tiny beadings that are in the curve of the front hood cover!

On the web I could find some shots in the "naked" state:

found at: https://www.facebook.com/196382207916011/photos/pcb.242331009987797/242330756654489/?type=3&theater

Kemna_Walze-Gigant-8_355 (fspg2)

Kemna_Walze-Gigant-8_356 (fspg2)

Kemna_Walze-Gigant-8_357 (fspg2)

And then Peter showed his great solution with his depressed beadings.
Maybe you can set your picture here so everyone can see it?


I know you will create those details and I know they will look perfect.

But you're crazy.



Sometimes it's fun to be a bit crazy ;)

On 2019/08/25 I wrote:

QuoteIn a few days I will get the part in brass from wax-lost casting.

I forgot to report the result.

After my order was accepted in Brass-Raw (Professional plastic was immediately rejected because of too low material thickness), 3 days before the confirmed delivery date a rejection of Shapeways came: ... "too small wall thicknesses".

The order at another provider was delivered within one week.

After removing the still visible pressure levels from the lost-wax plot with a small sander and sandpaper file, the tiny numbers (letter height = 0.9mm, grandeur 0.2mm) were still readable.

Next time I will have the wax plot of such small objects created by another provider, Volker had very good experiences ... maybe a bit more expensive, but the rework should be minimized significantly.

Kemna_Walze-Gigant-8_348 (fspg2)

Kemna_Walze-Gigant-8_349 (fspg2)

The parallel delivered front hood rounding I sandblasted only.

Kemna_Walze-Gigant-8_347 (fspg2)


Quote from: fspg2 on March 09, 2019, 12:40:14 PM
And then Peter showed his great solution with his depressed beadings.
Maybe you can set your picture here so everyone can see it?

By no means I want to hijack this thread - here the two pictures (front/rear).

"Simplicity is the ultimate sophistication" -Leonardo Da Vinci-



Gentlemen, the parts each of you produced turned out superbly. -- Russ

Ray Dunakin

Visit my website to see pics of the rugged and rocky In-ko-pah Railroad!

Ray Dunakin's World


Peter, thank you for the solution you showed with the great result! Let's see if I can do it that great one day.

In the meantime a little more time has passed than I actually wanted, but there were and are a few more things besides the hobby.

Yesterday evening I tried to mill the hinges for the swiveling hood of the Kemna Gigant 8 roller.

Scharniere_0,8mm_Loch_02 (fspg2)

The eye has a diameter of 0.8mm, the outside diameter is 1.2mm - this results in a wall thickness of 0.2mm.

Scharniere_0,8mm_Loch_03 (fspg2)

I milled these parts from existing 2.0mm MS58 material.

Scharniere_0,8mm_Loch_05 (fspg2)

Scharniere_0,8mm_Loch_06 (fspg2)

I don't really like the proportions yet!
The outer diameter could be brought to 1.0mm and the width of the individual hinges would have to be approx. 0.2mm wider.

Let's see if I can try again with 3.0mm brass.

To do this, I would first have to mill a pocket to bring the material to 2.2mm thick. Then I could drill the holes in the material with a 0.5mm drill (instead of 0.8mm).
Then it will be exciting to see whether a slightly longer 0.5mm milling cutter mills the outer contour into the brass just as well ...:?:

The 0.5mm milling cutter I have used so far has a cutting length of 2.2mm. This length is no longer sufficient to plunge approx. 0.2mm into the material below.

Scharniere_0,8mm_Loch_07 (fspg2)



Ah, here we go! I am already curious, there is always a lot to learn.



Maybe you will do better next time but it already looks quite good. -- Russ

Bill Gill

That's really good work! Is the rollers internal combustion engine also going to be operational? :)


Thank you for the kind comments.

So today I started a new attempt.

For this purpose, the eye was reduced from 0.8mm to 0.5mm, so that I got an outer diameter of 0.9mm, the width was widened from 2.0mm to 2.2mm.

Scharnier-Vergleich_1,2mm_zu_0,9mm_1 (fspg2)

From a purely visual point of view, the hinge has come much closer to the original by reducing the outside diameter of just 0.3mm!

Scharniere_0,8mm_Loch_10 (fspg2)

A recess of 0.8 mm was milled in 3.0 mm MS58 in order to obtain a residual material height of 2.2 mm.

Then the 0.5mm holes were drilled. A 5.0mm long 0.5mm milling cutter was used for the outer contour.

Scharniere_0,8mm_Loch_11 (fspg2)

With such thin cutters I usually proceed cautiously,  too often a mishap has happened to me - too fast, too deep ... crack!

In between times I used the compressor to blow open theslots. The last pass was milled through and the MDF material was scratched 0.2mm deep.

Scharniere_0,8mm_Loch_12 (fspg2)

The two following images refer to yesterday's milling in the 2.0mm brass material.

Scharniere_0,8mm_Loch_08 (fspg2)

After the last pass, the milled part got stuck in the plate by small retaining bars on the lower beam. I then separated everything with a thin craft knife.

Scharniere_0,8mm_Loch_09 (fspg2)

10 hinges in one go takes about 40 minutes now.

Scharniere_0,8mm_Loch_13 (fspg2)

Here again the comparison of the two hinge variants.

Scharniere_0,8mm_Loch_14 (fspg2)