Did you know that I only have 2.5 weeks to finish Ãœberclocker? I technically do have a whole month until Dragon*Con, but only 2.5 weeks remaining around 24 hours of machine shop access and piles of potential parts. Back in the dayâ„¢, I’d have to plan for weeks to take advantage of a few hours of machine work at most.

I’ve been totally spoiled by machinery. Hey Dale, I think I’ll just camp out in your shop space when I get back.

Anyways, work is shifting towards completing the fr0k assembly. The frame and running gear, at this point, is complete, since I recut the bottom plates a few days ago. One of the fr0k gearboxes (the so-called “überghettofrakenb0xen”) is complete, and the other is coming. The fr0k actuator awaits springs from McMaster. After that, it’s all electrical work.

And Pop Quiz needs a blade. Like, now. But, first, Ãœberclocker.

I lied when I said the frame was complete. I got these Mabuchi 700-frame motors from Banebots and plan to swap them into the drive gearboxes when it comes time. Although this is not a priority, I would like stronger drive motors for Ãœberclocker if I can manage it.

Two 500-size drill motors, while punchy for a 12lber, is cutting it close for a 30lb ‘bot which needs its drivetrain as part of its weapon. Especially carrying another opponent – a gross weight of 60 pounds – the drive will be heavily stressed.

The motor swap should be relatively simple. Some drill gearboxes (not sure about these yet) already have the mounting pattern for the larger motors built in, as some 18 volt drills do have these larger-sized motors. The 15 tooth pinion on the 900RPM gearboxes have plenty of beef to bore to 5mm.

If not, I’ll just modify the motor mounting plate. I would get a few of those drills from Northern Tool to play with, but the two-stage gearboxes require a redesign of the back half of the bot. Not smart when the back half of the bot is already made.

Top and bottom plates. The top is from several weeks ago (the only part out of like 10 that the jet didn’t eat), and the bottom two are new. I made the rear bevel armor out of some .075″ steel for added protection and mass (though it’s still under a pound).

The steel is also dichromate plated, which gives it the weird rainbow effect. It doesn’t speak much to Ãœberclocker’s masculinity to run around with a giant rainbow-colored ass, but makes it all the more funny when it defeats opponents.

The garolite holes have minimal delamination. I found that the best way to avoid it is to just punch the hole and cut as fast as possible, essentially completing the hole before the high pressure water has time to force the laminations apart except in a very localized area.

And here they are mounted. Not all the holes on the beveled end line up (due to sketchy geometric projection and even sketchier edgefinding), but UHMW is pliable enough and the error small enough that I just let the countersunk screws align themselves.

Freshly gutted drill gearboxes lined up like freshly butchered meats.

It takes three drills with metal gearsets to make two überghettofrakenb0xen, since each one uses three planetary stages. I needed to swap the 15 tooth pinion on the 18v motors for the 9 tooth pinion on the not-18v motors.

Making the aluminum gear housing for the ÃœGFBs. To do this, I made some 2″ diameter, 1.325″ long cored rounds on the lathe, then finished on the mill (since there isn’t a proper boring setup for the lathe). The boring head is my new favorite tool.

I machined a light flat onto the casing before starting – this is so a plain milling vise with no V-channels can grip the round part effectively. Also it was to ensure I can remount it in the correct orientation.

Sectioning off a drill ring gear to use as the first stage. Being made of sintered steel, it absorbed alot of oil from the grease in the gearboxes. Result: dense grey smoke cloud, but the self-lubricating is nice.

And the ring gears installed. I (not purposely) used a massive, massive press fit for these parts. The drill ring gears are 1.495″ in diameter. The hole I bored was supposedly 1.490, but turned out to be 1.485… It took a very, VERY large torque bar in the vise and the grace of the Robot Gods to squeeze these rings in.

There’s a tiny bit of offset in the teeth between the half-ring and the intact ring, but that doesn’t affect anything, since the first stage fits fully in the confines of the half-ring.

I anticipated having to use set screws or something to keep the ring gears from rotating under high-torque loads, but if they let loose now, something has gone horribly wrong. Although this giant press fit was accidental, I’ll probably reproduce it for the other ÃœGFB

In a moment of genius (or perhaps insanity), I discovered that the chain breaker tool acted as a nice gear puller for the drill motors. It worked on the 15 tooth pinions fine, but did not on the 9 tooth ones.

Two gigantic flathead screwdrivers came to the rescue for that.

In another moment of insanity, I discovered that sticking a magnet on the end of a ratcheting 1/4″ box wrench made a very low profile right-angle driver that takes any 1/4″ hex screwdriver bit.

I’ll probably permanently epoxy the magnet onto said box wrench later on and press this into service as my “I-suck-at-designing-serviceable-machines” tool.

The basic form of the ÃœGFBs. These are not independent assemblies – they are designed to mate permanently to the fr0k main support towers.

A serendipitous side effect of cramming the drill ring gears into a space that was .6% too small for them was actually increasing the precision of the gearboxes somewhat. I noticed that I had to align the gears more before they’d drop into their pins, and the whole thing has less backlash and “wiggle room”. Presumably the slightly too-small ring gears cause more tooth contact – this is a good thing.

One small issue arose from the fact that I never fully measured the inside of a drill gearbox – only speculated on the length of parts based on the ring gear dimension. This was fine when I was making housings for stock two-stage gearboxes, but adding the third stage threw off my width calculations.

Result? Pilot ring on the motor mounting plate doesn’t go all the way into the ring gear housing. In fact, it barely goes in at all. The gearset sticks out so much that it’s better to leave the mounting plate flat and let the remaining space be “wiggle room”.

….so I turned the mounting plate around. I actually did make a new one, since the motor mounting holes had been counterbored halfway through. Now the ÃœGFB is a nice fit.

And I need more 4-40 cap screws, but the hardware store isn’t open this time of day.

I have taken over 100 pictures of the build. I take an excessive amount of buildpics.

This is actually not a bad thing. I have grown to like documenting my work as much as I can manage. You know, so in case I lose my memory for some reason, I can find out how to do it again.

Yes. Anyways…

More drills! I got some more 18 volt drills off mysterious, sketchy Yahoo Stores. Oddly enough, now that I’m actually looking for a 18v drill with the standard 36:1 gearbox, I can’t get one. Yes, these are the 900RPM type. Handy if I want to have a spare gearset for the drivetrain (which I do).

So, for the curious, the Great Neck “brand” of imported 18 volt drills also have 24:1, 900 RPM gearboxes. I’ve seen these at multiple retailers, like this.

Down to business. I couldn’t find any 4-40 cap screws, so I had to assemble the clamp actuator temporarily with little computer standoffs. Here it is mounted to its pivot by a shoulder screw and spacer (one of my new favorite building methods). The actuator is free to swing on the pivot point.

In yet another episode of “How the hell am I going to put this together?” I discover that screws do indeed have heads. This one contacts the sprocket, and will need to be counterbored a bit into the clamp arm in order to pass the chain later on.

Onto the actuator again. Here’s the beginning stages of the leadscrew assembly.

The 3/8-12 Acme screw has one end slightly turned down and bored to fit the 4mm shaft of the B62 motor. A 6-32 set screw drilled down from the screw surface holds onto the shaft flat and transmits torque (You can see it barely sticking up by the bushing).

This turned down section also runs in a short 5/16″ bushing. So, between the B62’s output bearings, the close 4mm shaft fit, and the outer bushing, the screw itself is pretty stiff.

The other end of the screw is also slightly turned down for… Well, I don’t know. It must have been for something.

With the leadscrew firmly stuck on the motor, it was time to work on the other end of things. The clamp hinge-pivot-clevis-trunnion-whatever is a multipart assembly consisting of the leadscrew nut, a nut holder (LOL U SED NUT), and the aluminum cutout of the pivot block. The nut holder is made of a 1″ round of steel.

Yes, I chucked an endmill and was using it to drill holes. How else can I get smooth, clean, flat-bottomed holes in a single shot?

So things got a little too hot during the turning process (by which I mean I was jumping back every few seconds because another smokingly hot oil-covered steel curly sliver would land on my arm). Using mad engineering skills, I make a convenient chip guard.

The lathe stepped up the game by firing chips under the guard. I bit it and just put on some welding gloves.

To keep the assembly together, I turn to my perennial nemesis, the retaining ring. I hate retaining rings with a passion – that’s why I use them, of course. To ease my suffering, I actually went and bought a set of retaining ring pliers with interchangeable heads.

Conveniently, a giant hacksaw blade measures in at the exact right width to cut a slot for this retaining ring. And so the Amputee’s Cutoff Tool was used to slot the nut holder (with the spindle running, duh).

A quick trip to the mill to add a hole and a slot and I have a nut holder (so I don’t have to hold my own nuts, of course). The hole is an on-the-fly part design change, since I figured a press fit was nice but not very serviceable.

Add one leadscrew nut. A set screw keeps the nut in place. Since this nut should only ever see a compressive load (lifting robots with the clamp arm is a bad idea), I don’t count on this being too much trouble. However, it’s equally less trouble to drill the set screw hole into the nut itself, so that might happen some time too.

The 100th Ãœberclocker build pic is of the nut assembly. Add to the nut holder assembly the pivot block and two Belleville discsprings, and it makes compliant clamp arm. When the arm clamps down onto an opponent, the motor will continue to drive the nut assembly (since it floats in the pivot block, held in by the retaining ring), compressing the springs and adding a bit of “preload” to the clamp arm. This means the entire system doesn’t have to be wound up in order to clamp firmly.

It adds a bit of compliance to the system, but is not designed to save the assembly if the opponent decides to force its way out of Ãœberclocker’s grip. The next failure point down the line is the end of the clamp arm itself.

Unfortunately, I couldn’t actually test this part, since I redesigned the nut holder on the fly. Originally, a bronze bushing separated the pivot block from the sliding nut assembly, and the neck of the nut holder was 1/2″ – which is what I ordered springs for.

However, in a fit of laziness and after discovering I didn’t order these bushings, I just decided to make the neck a bit wider and run it directly in the aluminum. It’s moving all of 0.1″ maximum – does it really need bushings? There are things in this world that don’t need bearings since they won’t last long enough, move fast enough, or need enough precision to warrant any (Ãœberclocker’s clamp arm is all 3).

Of course I forget the springs no longer fit – time to get different springs.

Shoved onto the leadscrew assembly, the (almost) complete clamp actuator. I don’t have the little metric screws to mount the B62, nor 4-40 socket head cap screws to attach the actuator body.

However, it’s fun to just putz the thing up and down the leadscrew. I didn’t get the “precision” Acme nut and screws, but it’s still very smooth, and can push with an absurd amount of force – theoretically over 200 pounds (translating to about 30 at the end of the clamp). Dunking it in some EP grease should make it even better.

While I was waiting on some people to finish welding in the machine area, I finished out the drivetrain on both sides by mounting the motors and adding belt tensioners. To dismantle the drivetrain easily, I only have to release the large tensioning roller, freeing up enough teeth to slide the wheels off.

There’s enough tension in the belts to not slip on the motor pulley under constant (hold-wheel-down-on-table) load, but only a drive test will reveal the true performance.

It’s ALMOST THERE!