Caterpillar D-7 Project

[Firemodeler1]

Posted elsewhere is the M-20 prime mover project that includes an M-9 trailer.  This is the load that was intended for the M-20 to haul around.  It started out as a 3D printed kit from Scale Collectibles (Romania).  From there it took on the form of the D-7 which was a mainstay of the US Army during WW II.  The kit came with hydraulic lifting for the blade but I liked the old cable lift better and modified the build accordingly.  Here is the in-progress sequence of the build.

These are just some of the kit parts as they came out of the boxes.  Each part was bubble wrapped and the lattice work had to be removed from each as well.  Parts were perfectly formed and smooth.

Tracks came in 4 pieces each and had to be assembled in a certain sequence to get the proper fit.  There are no instructions with this kit so on-line photo sources needed to be used as reference.  I also used two photo reference publications from David Doyle Books.

Testors olive drab was used for paint.   It went on smooth and dried quickly.  I washed each piece in warm water and detergent before painting.

The basic build is complete.  Next up is the LeTourneau power control unit and cable frame for raising the blade.   The tracks were first painted brown primer and then highlighted with Tamiya weathering colors.

I used the Tankograd photos for reference on building the LeTourneau unit.  I also found the patent drawings on line and used them to scale down the drawings for the correct size.  It is made mostly of 0.020 and 0.010 Evergreen sheet plastic.  The two drums rotate inside the housing.

The cable frame is made of brass stock.  Pulleys inside the housings are turned from brass rod stock.  The cable is metallic embroidery thread.

Here's the final build sitting on the M-9 trailer.  Doc Obrien weathering powders were used to simulate the red soil that was encountered in the area of activity.

When connected to the M-20 prime mover the entire model is 25" long.  The build is 1/25 scale.

 

 

[AP40rocktruck]

I also have the 1/25 scale printed D7 from Romania.  So far they have done 3 crawlers in 1/25.  Only 2 were put on the market.

 

[Firemodeler1]

Have you put yours together yet, Richard?  I ran into a couple of minor fit problems during the build but they were easily corrected.  Most were in places that are hidden and a small amount of sanding and filing did the trick.