KEMNA street roller in scale 1:22.5

[finescalerr]

The difference is more visible than I expected. Nice job. -- Russ

[Ray Dunakin]

Holy cow! I thought the first batch was impressive, then you managed to improve on it!

[fspg2]

At the front of the Kenna Gigant 8 there is a curved front panel with an "inspection flap" which has a round, reinforced edge.

The first consideration I didn't really like - I wanted to mill a 0.3mm recess in a 0.5mm thick MS58 sheet with a 1.0mm ball end mill to solder a correspondingly bent 1.0mm wire into it.

My first attempt at making everything from a 1.0mm MS58 sheet was not crowned with success. I had milled the plate down to 0.5mm thickness with a 3.0mm router bit. Only the 1.0mm thick edge of the lid remained and was wound inside and out with a 0.5mm quarter round cutter.

Revisionsklappe_Kemna_Gigant_8_06 (fspg2)

 
It doesn't look good in the sharp side light. What happened?
I usually use Gudy870 to glue my sheet metal to be machined onto MDF boards, which are then attached to the router.
I had done the planing of the surface in small increments (0.2mm, 0.2mm, and 0.1mm in succession), relaxing the sheet so that it curved slightly upward from the center, thus removing more of the material during the subsequent routing passes. In the middle, it is now only 0.15mm full 0.5mm thick.
I had also used an old remnant piece here, where the milled out piece was not fully glued on.

What ultimately led to success?
Two parts were milled. A 0.5mm MS58 sheet received the oval cutout. The lid with edge (milled from 1.0mm material) will be soldered into this later.

Revisionsklappe Kemna Gigant 8_01 (fspg2)


Since there was still a leftover piece of 5.0mm MDF on the milling machine, I quickly milled a small bending gauge.

A straight lower part is followed by two different radii.
The bending gauge itself has two radii, each reduced by 5.0mm, so that the annealed sheet is overbent and can then spring back to the desired bend.

Revisionsklappe_Kemna_Gigant_8_08 (fspg2)




Revisionsklappe Kemna Gigant 8_02 (fspg2)


Revisionsklappe Kemna Gigant 8_03 (fspg2)


Revisionsklappe_Kemna_Gigant_8_05 (fspg2)


I had a phenomenon after annealing the 0.5mm sheet: The width of the oval cutout had decreased from 25.0mm to 24.9mm. To be able to solder in the lid, I have to file a little.

Revisionsklappe_Kemna_Gigant_8_07 (fspg2)

[finescalerr]

Almost no other modeler in the world could match your results. -- Russ

[Bernhard]

Nice to see that this project is going on as well. As always, it's interesting and inspiring to see which method leads to useful results.

Bernhard

[Ray Dunakin]

Fascinating!

[Sami]

your works are carried out with great finesse and your templates inspire me for my future constructions.

[Lawton Maner]

How much over bending do you allow for spring back?
 
The same idea without spring back allowance can be used to bend polystyrene in concert with an oven.  Most importantly done when the wife is out of the house.