CAT 586C


My favorite constructions vehicles are feller bunchers. The wheeled ones. So I am naturally inclined to make them. I built a small one; I built a large one. I wanted to build a medium one, but I figured I should get out of the box. At least this time.

The full gallery may be seen here.

CAT 586C

The CAT 586C is a site prep tractor. Forgive me for simplifying the work done by the engineers, but the tractor is basically a 573C with a new implement for site preparation, rather than felling. As always, I stared with scaling the full tractor from CAT’s website, and finding a size that would work well with tires, features, and aesthetics. Then I started building.

CAT 586C Rear

I started with the chassis, to get a sense of the size and the layout. I had a good idea of all the features I would want, and I knew some planning would be required. I then finished the mulcher (implement), which is basically a rotating drum with lots of teeth on it. I used a bunch of 24 tooth gears, and connected them to a rotating driveshaft. The chassis was built with four wheel drive, and was connected to the mulcher driveshaft through a series of gears to increase the speed of the drum.

CAT 586C Underside

Then on to the back of the tractor. Feller bunchers and site prep tractors all have their engines in the back; pretty normal for large tractors with large front implements. But to get the weight as far back as possible, the engine is mounted transversely. This presented a couple of challenges for me. I mounted a I-3 engine on the left in the rear with simple gearbox geared up to connect it to the drivetrain. Just in front of the motor are the two cooling fans, which are also driven by the drivetrain. These are also geared up. For those of you keeping score at home, the drivetrain gears up three separate functions, so rolling the MOC on the floor causes a nice whizzing sound.

CAT 586C Driveline

I added some additional features that mirror the real tractor. First, over the mulcher there is a guide bar that allows the tractor to push trees and shrubs down toward the mulcher. In my MOC this is accomplished by a simple worm gear mechanism. Second, I added a small winch on the rear to get the tractor out of sticky situations. Finally, a small mulching door was installed to allow for more or less entry to the mulcher, again just like the real tractor.

CAT 586C Mulcher

The tractor worked well. Functions were smooth, and required no maintenance during play. The many controls on the front were a little dense, and this caused some finger congestion. The number of rotational features connected to the drivetrain made rolling on the floor a little strained. Thought, this kept the MOC from rolling off the table into a lot of pieces. Everything worked well enough, so maybe it is time to make another feller in this scale. Not today, I still have a lot of other projects to complete first.

Happy Building.

JCB 930 Forklift


It was time for me to to make something that was a little smaller with a lot of functions.  I kept driving by a JCB forklift on the way to work, and I thought I could make that.  I wanted manual functions, including a working fork tilt and dual stage lift, working steering and drive, and a yellow bodywork.

I always start with the hardest part of a model.  For this model, that was the fork.  I wanted to use a dual stage lift as to get the forks to a substantial height.  This design would require a chain that would wrap over a moving frame, and connect on one side to the forks, and on the other side to the body.  The moving frame would be moved by a screw, thereby lifting the forks.  I used a number of worm gears on two 12l axles, connected through the bottom to move the moving frame.  This setup allowed for a pivot point, and a lifting mecanism that would function much like the real JCB 930.  The moving frame consisted of two rows of liftarms, and the forks tied everything together between the moving frame and the worm gears.  A chain went up and over the full assembly to work move the forks as the moving frame was lifted.  It works like this.

I then worked on the driveline.  I added a 3 cylinder motor in the rear, driven by the front wheels, working to keep the functions out of the way of the fork mechanism.  I added a steering axle on the rear, and gave it a pendular suspension setup.  This allowed for some stability on uneven ground, while keeping the front wheels planted for the load as it had no suspension.

I then built the body after the JCB 930, and as I did, I added a tilt freature to the fork.  This feature did not work too well, but it gave me the ability to adjust the pitch of the forks, which we a design requirement.  It was not too stable.  After a little work to the body, and a HOG steering link out the top of the cab, the model was done.

The model worked well, particularly the lift feature.  I was a little disappointed with the tilt feature, as it was a little too wobbly. The drivetrain worked well, and the steering allowed for tight corners.  The suspension give good stability, and offered a little bit of off-road prowess.

The full gallery is here.

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