Cat 340D Excavator build

[frizzen]

I like it on those tracks on it, looks kinda like it's set up for extra stability or lower ground pressure

Are the motors running track from center, or does it chain drive to and end sprocket?

[crueby]

Hi Frizzen, there is a chain drive inside the tracks, with a 1/4" pitch bike style chain. Sprocket on the shaft with the motor, chain up to another sprocket on the track drive wheel. The drive wheels were two part castings, so I trimmed one side to make room for the sprocket in the center of the hub. That way the chain is not visible without looking inside. Having the chain inside made for some trade-off with the design of the track road wheels down the length, had to make them a little larger so things would clear.

[crueby]

Got the bigger/stronger gearmotor installed for the main boom raise/lowering, had to rearrange a few things to get it to fit in the cab. It works much better, the original one was barely able to raise the boom assembly. This one could be just a little faster, may swap up to the next rpm range on it (they come in a series of gear ratios). This one is quite a bit longer, so it has to sit sideways in the cab, and have a bevel gear set to attach it.









The shop elves are measuring things up to make a rack to hold all the speed controls, they are just temp wired in using some terminal blocks to test things out, want to have them all in a row and the wires neatened up from the current rats nest.









I was able to test out the crawler track motors, went for a long trip of about 6 inches back and forth on the bench. Looks good there too.

[Originalrob]

Looking great ! your progressing very well and will be digging soon !

keep up the good work

[crueby]

Thanks Rob!


I was taking a look at the travel on the bucket, it is not opening up as far as it should, looks like I need to adjust the positions of the links and cylinder a little bit to get the proper travel. The cylinder needs to move up the stick about 1/2", and the pivot hole for the bucket at the end of the stick is a little too far out the bucket, which messes up the geometry somewhat. That hole can be re-drilled farther in towards the upper lip of the bucket and the old hold trimmed off, so that will be easy. The cylinder moving will just need moving the mount holes for the upper brackets, and shortening the flex shaft to the motor. The joys of scaling up from such a small die-cast model!