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Getting parts together |
Building the Chassis |
Installing the Drivetrain |
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Electronics |
Armor |
Weapon |
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I had a major setback that essentially cost me a week's work, and cost me my front suspension, but that might be a good thing. I'm still paranoid about weight since I haven't built the disk yet. There's a lot of material in this report, and I'm well into the middle of the stuff that'll be in the next report. Even though it's kind of a waste to show the construction of parts that won't get used, that is, after all, about half of the Strike Anywhere reports, and there might be something to be learned
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Dan of CruelRobots.com graciously re-keyed my hubs to the 3/16" slot that my sprockets used. Here I'm trying to get a measurement for how deeply to cut the keyways with the hub on the end of the shaft, a piece of keystock, and my little steel ruler (You ain't a Machinist if you don't have a little steel ruler). Somehow I never ended up using this measurement, but I should have. |
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With the sprocket and the hub in the position I wanted on the shaft (The bearing and shaft collar are hidden below the sprocket), I marked the end of the keyway on the shaft. |
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"How do you get a shaft straight so the keyway goes right down the middle?" This is something I asked David a long time ago. He said to use a dial indicator and run the table back and forth to measure the position. If the needle doesn't move, the piece is parallel to the table. The square is used to make sure the end mill is centered over the shaft. Because of the way I turned the shaft ends, there's a little dot right in the middle that is handy to align with. |
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IF you happen to take the shaft off the table and you need to cut it more deeply, laying your little steel ruler across the edges of the keyway will enhance any out of level condition to the point you can see it. |
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Finished keyway. |
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Okay, I cut them a bit long. Actually, the extra slack came in handy. |
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This is a 2" Hangar Bolt. It costs about a quarter. They are, in my opinion, the perfect solution to the mounting of Colsons to Hubs issue. |
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The hub is inserted into the wheel, a 1/4" drill bit is used to drill the hole for the first hangar bolt. The bolt is installed. This fixes the hub so that all the rest of the holes are in exactly the right place. Note that normally for the lag-screw portion, you'd use a bit smaller than 1/4", but since the hole is so close to the bore of the wheel, the plastic swells to the point you can't insert the hub without shaving the bore. Too much work. The screw threads are larger than 1/4" anyway, and it saved me from having to swap bits for alignment (See the Bushings for the EV's in Strike Anywhere for the drill swapping alignment trick). |
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Since I'm tightly sandwiching all the components, I'm running the bolts flush with the hub. But you could leave them protruding and apply nuts. The joint is SOLID. |
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Did all four in one day. |
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Welded in a support for the rear motor mount. |
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And finally, I was ready to bolt all these components in. I was Psyched that this Bot would be on the wheels by the weekend. It was Thursday, October 4th. Little was I to know that a bunch of big Time-consumers were coming. With this drivetrain installed (on both sides), I applied power. It was cool! But I noticed a lot of resistance, and it didn't coast. It was also hard to get the bearings lined up with the holes to bolt them in. The Bronze Bushings are like a ball joint in the pillow block, as you'll see below. They're meant to stay aligned on the shaft no matter how the block is positioned. Really handy if you're not totally precise, or if your bot gets bent. But as they come from the factory, they're REALLY tight. So I had to loosen them up. |
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See, this is what they do when the shaft is out of alignment. What I did to loosen them up was put in a long piece of leftover shaft, and I started rowing the bearings around, so that the ball loosened up in its socket. You can see the accumulated crud as they smoothed out. The problem was, it took a long time, and there were 16 of these suckers. I wasted a day on them, and some of them wouldn't loosen up beyond a certain point. |
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Finally I got smart, and put the bearings in the lathe, and used another one to support the shaft as I moved it off axis. Some of them were STILL stubborn, so I wiped a tiny bit of 120 grit aluminum oxide from the sandblasting cabinet on the outside of the bearing. BAM, that loosened them up fast. I then used WD-40, and a kerosene bath to rinse all the grit out. It still killed a day, but at the end of it, I got the rear drivetrain reinstalled Friday night. |
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The camera happens to fit into the front wheel pod, affording this interesting view of the rear drivetrain install. The angle brackets in the front are for the motor mount. This particular picture also showed me that I needed to go back and fix the weld on the brace. Getting this all together is what happened Saturday. |
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Sunday I made the front Drivetrain frames. The sad thing is, I ran some 1/2" rod through the pivot holes in the back, but I guess something wasn't square. These were both skewed by about 1/8" but in opposite directions. I figured between the bearings and such, it would be okay, and give me a little Toe-in effect. |
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Time for a new wheel in the cutoff saw, donchathink? |
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So, here it was, Monday, I thought, "Okay, a little behind schedule, but I'm getting there." Ha! But I would like to point out a few features of this design. Note that all three axles are in the same plane. Also, with the pillow blocks on opposite sides, using washers is very effective at adjusting chain tension. |
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Tuesday I made new motor mounts for the front pods (The one in the picture above was a screwed up one). |
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As an aside, I wanted to point out that I intend to use nylock nuts in the final assembly of everything. If you do too, I highly recommend buying some REGULAR nuts as well because you'll be assembling and disassembling stuff a lot. (I'll be using washers then as well). |
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Mounts installed. Note the angle iron on the bottom of the motor portion trimmed for a fractional weight savings. "Snort!" |
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Remember kiddies, make a left and a right! Remaining steps, make the wheel inserts (Since the hubs aren't all the way through) and trim the shafts. |
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Aluminum makes some of the BEST curlies! Drilling out the wheel inserts! |
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Since the front pods were narrower, I needed something instead of the shaft collars to go between the bearings and the sprockets so that things didn't rub on the square tubing. 3/4" washers had an OD too large, but 1/2" washers were perfect, they just needed a bigger hole. |
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The pods were installed, temporarily using some 1/2" rod. I was going to make supports to use 1/2" grade 5 bolts. But, if you look at the pod in the upright position, it's not fully retracted. That's because I had to move the motor because the frame was narrower than I originally planned, and the motor hit the upper crossbar. MAJOR problem. Plus the 1/2" rods bent with little force. I was SO hosed. This was Thursday, the 11th. And I STILL had to figure out how to install the springs. Time for plan B. |
Or, "Why is it that Plan B is always more likely to succeed than Plan A?"
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Friday I worked like a madman. I was determined that if I didn't get it on the wheels last weekend, I'd be damned if I didn't do it THIS weekend. (And the clock is going tick, tick, tick, in my head as the event approaches). First, a new plan for a fixed drivetrain. Since the sides aren't straight, and the axles are already cut down, it would have to be an inset frame, and strong to take the down force from impacts. Paper Aided Manufacturing helps me mark the locations for support brackets. |
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Brackets are welded. |
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A new frame is constructed to hold the pillow blocks. You'll note I took NO chances with anything being out of square THIS time. |
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Preparing to install the frame. Note the piece of scrap used to maintain the distance between the arms of the frame. This was carefully checked for square to the crossbeams, then thoroughly clamped into place. |
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And then welded to death. That was it for Friday. |
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Saturday, it was time to install motor mounts, and the drivetrain components. Here's the top view. |
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And the bottom view. |
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YeeHaaa! Strike Terror is on its wheels. Now to install the electrical components, the armor, and build and install the weapon. And HOW much time is left? AIEEEEE! |
But at least I can now stand on my bot! And I powered up the drivetrains. What Sweet, Sweet music those chains make when they sing. Had kind of a close call there with the motor connectors.
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