Cat 340D Excavator build

[Zabco]

Very nice work as usual! What is the boring head you are using on your Sherline mill?

[crueby]

Originally Posted by Zabco

Very nice work as usual! What is the boring head you are using on your Sherline mill?

Hi Zabco,


That is an APT boring head - it takes the same 3/8" boring bits as the Sherline, but is a much more rigid and accurate head. The Sherline one just pushes on the moving portion of the head in one direction, so its easy for things to slip when tightening it down. The APT dial moves the head both directions, and there are adjusting screws on the dovetail to tension it all - I've had much better luck with it. They do not make it to match the Sherline headstock threads, so I had to turn down an adapter and mount it in a mill cutter blank holder with a 1/2" hole. Taller than the stock one, but I think it works better. I do have the taller column on the mill, so it can handle the extra height for most parts.


Chris

[Zabco]

Originally Posted by crueby

That is an APT boring head - it takes the same 3/8" boring bits as the Sherline, but is a much more rigid and accurate head. The Sherline one just pushes on the moving portion of the head in one direction, so its easy for things to slip when tightening it down. The APT dial moves the head both directions, and there are adjusting screws on the dovetail to tension it all - I've had much better luck with it. They do not make it to match the Sherline headstock threads, so I had to turn down an adapter and mount it in a mill cutter blank holder with a 1/2" hole. Taller than the stock one, but I think it works better. I do have the taller column on the mill, so it can handle the extra height for most parts.


Chris

Thanks very much for info. I have a Sherline mill also and really like it but the one accessory they make that I really don't care for is their boring head for the reason you stated. I will have to look into getting one like yours. Keep up the great work, I really enjoy following your builds.

[crueby]

Got enough wired up to do some testing - the bucket and stick motors working well, the motor that drives the two cylinders on the main boom does need an upgrade though - with the weight of the booms and bucket extended out, it is really struggling. So, I need to either add some more gear reduction or swap out to a different motor with some more oomph. Still need to wire up the cab rotation motor and test that one...

[crueby]

Got enough of the wiring done to test things out, and swapped the main boom motor for a slower/stronger one which is pretty close but could be a little faster. Here is a short video testing the different functions out, moving slow so I didn't whack anything on the table and so I could learn which stick did what!


https://youtu.be/xkGL3TcqJPY

[crueby]

Another major assembly almost done - got the track frames/tracks assembled this afternoon, moving quite well. Still some more trim panels and brackets to go on, and need to pull the tracks off one more time to install the drive chains and sprockets on the inside. The chain sprocket on the center of the track drive sprocket is there, but there is another one in the center of the frame that still needs to be fitted. The drive motors will sit on the inside edge of the track frames, under the middle of the cab (one per track). As mentioned early on in the build, these are NOT true scale tracks for this machine, but are re-purposed from a RC Tiger tank model - getting me running a lot sooner, to see how the whole thing functions. They can be replaced later with better scale tracks if I get the time for it.

[crueby]

More done on the tracks - got the frames painted, chain drives installed, and fit to the frame. Here is a test assembly of the whole thing, will pull the cab/booms off again to turn the track assembly upside down to fit the motors to the bottom. It definitely is more stable now with the extra width and length to the footprint.

[crueby]

Got the motors mounted to the track undercarriage, ready to wire things in...