Making Tracks

[BK9300]

A considerable investment in time, and patience, already.  Going to be a substantial load for your M20!

[ChrisR]

Looks great!!

[Chariots of Fire]

13 hours ago, BK9300 said:

A considerable investment in time, and patience, already.  Going to be a substantial load for your M20!

Not so much I think.  The M-20 was designed to haul tanks so I don't know that the D-7 (not the D-8) will be any heavier.  The D-7 kit has arrived in the US.  Just waiting for it to clear NYC.

[Chariots of Fire]

Got two things going now.  One is to finish the Cat D-8 with the new track setup.  And the second is to build a D-7 from the 1940's from a Scale Collectibles 3D printed kit.  Here are some pics of each.

This is the AMT D-8.  I painted the track and side rails with brown primer and then highlighted the tracks using a Tamiya weathering kit that has silver and gunmetal.  Also some Doc O-Brian's weathering powders to simulate some light brown sand.  I added some wire connectors to the fuel injectors.  The exhaust is a section of aluminum tubing with a brass cover on the top that can be opened.  Still a ways to go.

The D-7 is a much smaller piece of equipment as proven by the comparison of the size and length of the tracks.  Track plates are nearly identical but the number of links is less and the curvature is less.  The tracks in the foreground of the next photo came from the 3D printed kit.  They come in 4 sections, two end pieces, a flat section for the bottom and a top section that droops a bit.  I added the temporary pins to hold them together.

And here is what the kit looks like.  It has some amazing stuff in it and a more amazing amount of latticework that is used to print the parts out by 3D.  What you are looking at below is the dozer blade and the frame that attaches to the side rails and the center of the blade.  There is also a radiator included in this printing.  The tracks were similarly printed before the latticework was removed.

Here's a look at the assembled kit.  Very well done and very smooth.  No visible layerng of any of the parts which I will post shortly.

[Chariots of Fire]

And here's a look at just some of the parts that came in 5 boxes; two shoebox size and 3 smaller boxes.  The Cat 4 cylinder diesel engine has been removed from the buildup lattice as well as the pony motor next to it.  Great detailing in each piece.

[BK9300]

Amazingly fine resolution in the printing of this kit

[Randy D]

Well I was loving your upgrades on the AMT but now you have my attention with that awesome looking print of the D7.

Randy

[Chariots of Fire]

On 9/20/2024 at 1:57 PM, Randy D said:

Well I was loving your upgrades on the AMT but now you have my attention with that awesome looking print of the D7.

Randy

I've started painting some of the parts.  They've been washed with detergent and warm water and allowed to air dry.  This is going to be a WW II dozer with a cable hoisted blade.  I started with Testors olive drab.  The parts take the paint very well and there have been no fisheyes or orange peel at all.  Very smooth.

[NerdmanB]

Charles I am always so impressed by your builds. I have 2 D8 kits to build so I will be watching this build. Who is selling the 3D printed D7, that looks amazing. Love everything you build . Brian 

[Ace-Garageguy]

Fantastic work, as always. And inspirational too, as always.  

[Chariots of Fire]

4 hours ago, NerdmanB said:

Charles I am always so impressed by your builds. I have 2 D8 kits to build so I will be watching this build. Who is selling the 3D printed D7, that looks amazing. Love everything you build . Brian 

It came from 1/25 Scale Collectibles.  Printed in Romania.  Not a cheap kit at all.  After the conversion from pounds to dollars about $180.

[Chariots of Fire]

Made some progress on the D-7.  All of the parts have been separated from the "sprues".  It was easier than I thought but you have to look for all of the little connection points and make sure that they are sanded smooth.  They are everywhere but in most cases not where they will be seen on the finished model.

Since I am doing this as a load for the M-20 Prime Mover the color is military OD.  Testors OD is a very nice paint and goes on smooth.  I used Tamiya TS-1 red brown for the tracks.  The tracks were then weathered with Tamiya weathering powders of gunmetal and silver.  Similar coloring was done the sprockets and edges of the sideframes although they will have to be made more prominently bare metal.  The dozer blade was first done with OD and then oversprayed with Duplicolor chrome.  The seats were done with Tamiya rubber black.  

Some minor adjustments have been made in how things fit.  I found that some mating surfaces were slightly curved and needed to be sanded flush.  Instead of using the kit pins to connect the track sections I used 0.080 evergreen rod.  Just the right size and could be snipped off similar to the cast ones.

The above two shots are just a dry fit to see how things go together.  Note the little pin marks on the seat back.  The slot is a guide for where the upper seat cushion goes.  The pin marks were sanded smooth but they are all but hidden by the seat back.  Tracks went together easily but there is only one way for them to go. Took a couple of tries to figure that out.  BTW there are no instructions with the kit.

Some of the parts as painted.  There are lots of parts still to go to finish the engine before it can be set in place.  When that is done the seat and control platform can be set in place.  It will take some adjustment, and I will have to find out what parts need to be shaved down a bit in order for the control platform to sit flat.  Something is a bit high underneath it.

The kit includes a hydraulic setup for the blade.  But most of the WW II D-7's had a LeTourneau hoist and power drum located either in front or at the rear of the frame.  The tabs shown on the push frame of the blade need to be cut off and a new hoisting sheave scratch built to take their place.  Then there is the frame to build.

This has turned out to be a fun build and a slight diversion from all scratch building.  The various pieces are beautifully printed.

[NerdmanB]

Thanks for the information on the price. A bit much for my social security check. I know it will look amazing in your capable hands. Keep posting and I will keep enjoying. Brian 

[BK9300]

Going to look impressive on your M-20's trailer - tremendous detail in the kit and with what you are planning for additions.

[Chariots of Fire]

This project has come together surprisingly fast and well.  The Tankograd photo booklet has been a great help with some of the little details.  But all in all the assembly has been easy.  Some minor tweaking here and there but nothing that is not doable.  I still have all of the control levers to go and have to make some decals; three for the gage cluster and then some numbers and stars.  The blade and LeTourneau hoist will be a scratch building project all in inself and will come a little later.  Plastic tubing was substituted for the 3D printed exhaust stack.  The latter was too thick.  Also the hold in the top cover was in the wrong place so I had to make a small shelf on top of the manifold for the stack.  I also added some levers for the pony motor clutch, throttle and engaging the diesel flywheel.  Testors OD has been used for the overall paint scheme along with Tamiya rubber black for the seats and Krylon red-brown primer for the tracks.  They need a bit more silvery shine before they are done.  Brass wire was also added for various lines on the engine.  Still a ways to go before calling it done.

 

 

[Gary Chastain]

Another high quality build going on there Charles, well done. 

[BK9300]

I've mentioned elsewhere that I find weathering a daunting process - yours turns out very realistic.  Looking forward to the scratch built hoist being added!

[Randy D]

Charles,   You have done a great job with this D 7.   The paint and extra detail work is really paying off!!

Randy

[Chariots of Fire]

On 10/28/2024 at 9:01 PM, Randy D said:

Charles,   You have done a great job with this D 7.   The paint and extra detail work is really paying off!!

Randy

Thanks, Randy.  Rest of the build is on hold for now as I am trying to finish up the trailer that will carry the D-7.

[Chariots of Fire]

With the M-9 trailer finished work picked up on the D-7.  The kit had hydraulic lifters for the blade.  I liked the old cable lift so a Letourneau cable control unit had to be scratch built.  Here's the beginning of the work.  

The body of the unit is done along with two cable spools and a plate for the rear.  There is a lot left to do to make the two pulleys that are mounted on top.  They are not used for the blade but in case the dozer happens to pull a pan scraper, they would come into use.

Roughly this is where it sits.  Some adjustment of the back of the dozer frame will have to be done to accommodate it.

The body of the unit is made of 0.020 and 0.010 sheet stock.  0.030 strip stock and one piece of sheet were used in other parts.  Hex rod bolt heads were used in back of the spools.

[Chariots of Fire]

Work continued on the winch for the dozer.  Details were added here and there to enhance the look.  As part of the build there had to be a way of securing the winch so that the blade could be raised in position once the cables are attached and to stay where put.  I hope this works.  The drum on the right side is where the cable will be attached.  Once the cable frame and pulleys are done it will be strung starting at the drum with a few windings of cable and then will be guided through the rear pulley to the front one and down around the pulleys on the blade.  The final attachment is a clamp that is wedge shaped.  There are no bolts or clevises that secure the cable.  Just the wedge that holds the cable through friction.  The harder it is pulled, the tighter it gets.

I made the operating lever so that it could put pressure on the center of the drum using a spring on the back.  The idea is that when the cable is wound, the friction from the lever will keep the drum from turning.  But by pushing on the lever against the spring the drum will be released and the winch can either be wound in or out.  I made a tool to fit on the winch center pin so I can turn it by hand.  I'll post another picture showing it.

Right now there are no pulleys that would allow the dozer to pull a pan scraper.  There is evidence that not all D-7's had this feature but it is one that could be added in time.  For now the winch is by itself.  I'm not sure that the winch is not a bit high.  Will have to check the photos of the real ones to make sure.  Right now it is just mounted on a pin that can be relocated with another hole.

 

 

[Biggu]

Fantastic, Charles.......

[BK9300]

Great update, Charles.  Very trick, how you made the winch operable - good engineering!

[Gary Chastain]

Outstanding fab work

[Chariots of Fire]

Here's the tool for turning the winch drum.  Not very sophisticated but it will work.   Two pieces of square tubing soldered together.