We started off today by paying a visit to Custom Sheet Metal and met Ron, who took our DXF and titanium, and led us back to their waterjet machine, and we got to watch the Waterjet in action. It never occurred to us that there would be white sparks as the titanium was being cut, but then we've only seen polycarbonate being cut before. With a pair of fairyweight-sized blades in hand, we headed back to the Build Space to see how much of a 'bot we could put together today. Hit Back after viewing an image.
You can see one of the blades there on the scale, along with all the other parts we anticipate using, and the news is bad currently - 161 grams - time to put the chassis on a diet! We hogged out a bit more material on Milly, and weight started to drop.
After drilling a few more holes in the bottom chassis section, and hunting down some 1.6mm metric screws we were able to install the drive motors to make sure they fit in the holes we cut for them.
Here's a bit more of the internal layout - the TinyESCs have been calibrated, so we snipped the jumper pins down, and tucked them into their slots, happy they fit. Of course, nothing's soldered yet ...
Now it's time to think about attaching the two halves of the chassis together. These are 1" long #0-80 screws, and we're going to have nuts sunk into the bottom of the chassis. We were going to use six bolts, but screwed up one of the bolt holes, so hopefully four will suffice.
Here we've successfully pressed a titanium blade onto the can of one of our favourite 2204-14T outrunner motors - it's a very snug fit, but we got it on without buckling the can, and added a round of Loctite to help keep it in place.
Here's the underside of the chassis with the #0-80 nuts fitted in 3/16" recesses. You can see at the front of the 'bot that we went a little ... overboard ... hogging out material, and this could cause some issues when it comes to mounting the weapon motor. We've also drilled and tapped the wheel hubs for installation.
The weapon ESC is a little bigger than we had originally thought, so we had to mill out a bit more of the top section to be able to fit it in, but it does fit, which is good!
It's about time to break out the soldering iron, so we need to determine at this point which way to plug the drive ESCs in so that forwards will be forwards. After marking the connections, we heat up the soldering iron and stick the leads to the tabs.
This was taken after a short test drive to verify that we have the wheels installed tightly and the motor connections hooked up right.
Our plan to get over the fact we milled a touch too much off the front of the chassis is to mount a polycarbonate plate to the remnant of the front slope, and mount the weapon motor to that. Unfortunately a 1/4"-thick piece is eight grams - which pushes a bit over the limit.
So we made a 1/8"-thick one, and that puts us just under 150 grams. Given that we'll be shortening wires, etc., we'll come out nicely within the weight limit. Tomorrow night we'll finish the wiring, and the 'bot will be done!
Subscribe
