Looks like I'm finally making some progress on this project. I have to say, this week was very challenging to keep my enthusiasm up. Lots of technical issues arose...but once I figured out how to work around them, my momentum picked up again. So...what did I get done since last time?
First off, I managed to assemble most of the parts for the digging arms. Now they're ready to be attached, once I get farther along on the other bits.
Here's where things started to bog down...making some gears. I drew up some plans on the computer, spray-mounted them to a 2x4, then cut them out on the band saw (one tiny tooth at a time). I tried some small triangular teeth first...took quite a while to do. But I soon found out that precision measuring and cutting are really crucial...not my strong points.
After failing at different variations, I finally found a website that had a little gizmo on it that lets you custom design patterns for gears. The larger teeth seemed like it would work better. Also, I decided not to make the gears so wide (from the 2x4 width) and used some half-inch hardwood board.
Here's the final version, and a little "gear box" that holds it all together. I've added the circular attachments where the digging arms will go 'round and 'round. The smaller gear at the bottom has the axle going through it that will be part of the hand-crank mechanism.
I then constructed some "cams" that will rotate on the axle, and push a "paddle/lever" up and down. This is what will cause the DiggerBot's mouth to open and close (by pushing a dowel rod to be added later). I shortened the paddle a bit from what you see below.
Finally, I made the "tank tracks" shapes that supports the gear-box. I will do a lot more detailing on those later...just wanted to get the main structure built. I'm still having some problems with the gears hanging up a bit, when I crank the handle. Hopefully, I'll be able to adjust some things later to fix that.
Okay...that's it for now...my head hurts from too much thinking this week!