Custom scale model builder Ad Gevers has recently started his next project of building his

Caterpillar D4D HGC Tractor

It is our goal for the coming period in this Making-of Caterpillar D4D HGC (High Ground Clearance)  Tractor to show how this custom model will be achieved.

As a basis for this project Ad uses as donor the Caterpillar D4D Small Dozer in 1:50th scale. This Golden Oldies scale model was released in 1970 by NZG NZG Nürnberger Zinkdruckguss-Modelle GmbH under #119.

Ad shares his building skills through the photos with little notes guiding us in the construction process. Gradually it shows the making of a unique model by using the donor Caterpillar D4D Dozer from NZG in 1:50th scale to create his one of kind Caterpillar D4D HGC Tractor.

Enjoy reading & watching!

Ad and Wouter

What preceded

Ad had had the idea of building the Caterpillar D4D in HGC version already for a long time.

But due to a lack of the right parts and (yet) no time and because of not making them himself, the project remained on the drawing board....

The Kickoff

....but when fellow collector and custom builder Andrea Nonnis from Brazil offered an HGC kit with the right track shoes, idler and sprocket for the Caterpillar D4D Dozer from NZG, Ad energetically started this new project.

The HGC undercarriage

For starters Ad has secured the sprocket cover plate so that they will both be the same size.

Ad first soldered four of these together, which was no problem, but then putting two of them together again to make the undercarriage went wrong. Too much heat entered the workpiece causing it to disintegrate.

The ultimately good solution was to make the undercarriages in one piece.

The next step in making the undercarriage is to install the bottom rollers into the new frame.

The axis is then assembled with the cover for the sprocket

Finally the running wheel can be placed and the first test with the custom 3D printed tracks follows.

The HGC upper structure

The original fenders were of course much too thick, so they were cut away as much as possible

The Caterpillar D4D Dozer from NZG is equipped with a cabin, so there is a slot in the fuel tank that needs to be filled for the HGC version that does not have a cabin.

Because the original undercarriages have been removed and have been replaced by the HGC versions, the spaces and places that have become visible must also be filled to fit to the new Upper structure.

Ad also made the new final drive and removed the reinforcement of the nose.

Super sleek: thin fenders!

The new grill. Secretly a lot of work, but more than worth it for the look of the machine

The top of the battery boxes are too round, so some small pieces of them have been cut off.

On the Upper structure, material had to be sawn away here and there for the installation of the new floor plate and the operating handles.

Due to all the adjustments, the attachment point with the undercarriage was no longer there and Ad glued it in again.

To complete this phase, Ad made some minor changes to the engine housing, such as the air filter and fin, but also the back of the radiator was overhauled.

The PTO shaft also gets its place!

The HGC towbar

Ad naturally fitted the Caterpillar D4D HGC Tractor with a functional tow bar. Made entirely by hand from brass material.

The HGC exhaust and control levers

The HGC hydraulic pipes

The HGC final assembly

All in all, a lot of changes have been made to convert the Caterpillar D4D Dozer into an exact replica of the Caterpillar D4D HGC tractor.

Everything in one overview! Final assembly and spraying can start.

The HGC type designation

The painting of the parts

After priming, imperfections always come to light and these must be filled with some filler. So that after a final sanding and polishing turn and a final check whether all parts fit, the model is completely ready for the careful degreasing of all parts and the application of the final coat of paint in the Caterpillar color.

Our choice is to make a spray can with the same color as the donor scale model. For this we rely on skilled Toon, working at De Beer Paints into their facility in Helmond, The Netherlands. Toon makes, based on a color sample of our donor model, our spray can on demand. Not cheap, but perfect quality paint with the exact matching color. Highly recommended!  

The Final Step!

For the finishing touch, the chair cushions and the handles of the handles are hand-painted matt black by Ad

Finally, Ad applies a layer of clear coat over the applied stickers for protection!

Done!

Now the model is "Ready for work" and it can be added to the collection in its display cabinet.