Last episode of this “Overhaul” “Build” “Report”, I straightened the frame from its accumulated damage and began drawing up a plan to put new motors in. Now it’s time to execute! I had no particular goal or deadline with this project, mind you. It was something I made incremental progress on if I wasn’t doing anything else, and I already had basically all the parts in the garage already. One of those (few) nice things about building a 250lb Battlebot is that future robots are basically free for a long time due to your initial “investment”!
First order of business: get the spider couplings mounted on the motors. These scooter motors have an odd stepped shaft that usually holds a #25 sprocket. I had to make a similar stepped bore in the spider coupling halves in order to get them to seat correctly. The shoulder starts at 8mm and increases to 10mm, so I ordered 5/16″ bore couplings to start with (0.3125″ vs. 0.3145″, an easy knock-through).
The motors don’t have a good way of attaching anything to the motor shaft except with the roll pin which the original sprockets used, so I had to drill a matching hole in the spider coupling. This was “interesting” to say the least.
I mean, besides doing this on a mill having no digital readouts, the hubs were very mildly tapered to release them from their sintering molds. That means I had to first machine a flat into one side in order to register it with the vise at all. Next, I squared up the backside against the vise with a parallel, right up on the edge. This was going to be good enough to drill one hole.
In lieu of another roll pin, I went for a 1/8″ diameter solid dowel pin for extra strength. The shocks of each shuffler foot hitting the ground, I suspected, wasn’t going to play well with the hollow and split roll pins.
Some time around this point was when I decided to absolutely send it with available materials.
I decided instead of machining and welding an endcap onto the “motor rails”, I would take a page from the finest robot arm additive manufacturing research and just lay a massive circular weld bead inside the tube….
…upon which I cleaned the bore, drilled to size, and tapped it just like a regular ol’ metal piece.
Are the threads clean? Mostly. Do they go all the way around? Moooostly. Good enough for this job?
That’s what I’m after.
These… uhh, “weldments” met the motor mounting plates fresh off the printer as well.
The standoffs that bind the motors together? Left over 30haul and Uberlocker leadscrew stock I’ve had for years! I mean, these aren’t serious high grade steel or anything. I used these in the absence of having appropriately sized solid aluminum or steel stock.
The motor “cartridge” completed and assembled. It’s bound together with 5/16″-18 hex cap screws.
On the other end, the flanged Ampflow adapter with bearings in it is mounted as well.
Here’s the totality of the setup, both shuffle pods and the motor cartridge.
To install this was a little strange, as Overhaul 1 wasn’t actually designed to have something dropped in from the top. I wiggled the motor cartridge in first through the side, then lifted one side up at a time to slide the mounting rails in and add shaft collars.
At first, this assembly is left loose to slide side-to-side on purpose, since I’d need to get the horizontal alignment constrained by having the shuffle pods in place.
Funny enough, I kept the original drive chains we cut for for the shuffle pods – they were used on Sadbot when it had a geared 63-74 motor per side, and still fit today using the same sprocket!
And now we have fully assembled and motion-ready shuffle pods!
Mounting these things was fairly easy, as I’d already blown out the frame rails enough that they can slide sideways again. Drop in, mate the spider coupler, and attach the four bolts.
Soon enough, they were ready for an “initial break-in”.
I performed a bit of look-ahead work by repairing some of the motor wires and running them through spare loom. This will be handy once the new electronics assembly is installed on the four rubber wubbies seen in the bottom of the image.
Overhaul was missing a few of the very large shock mounts, or mega wubbies, that had secured the pontoons. I had to order some new ones, and then remembered that they had to be “chamfered” a little to clear weld beads on the inside of the pontoon cross beam.
With relatively minimal complaining, the straightened out pontoon weldment goes right on. I might cut the Pull-Tab off later.
From here on, I’ll take out and apart the lift and clamp actuators and work on an electronics solution. I’ll probably keep this thing on 6S (24V) or thereabouts – there is NO need for the shuffle mode to go breakneck speeds like we had it at BBS1.