Tuesday, 18 March 2014

Massacre Build 5

Updates will be more frequent as I panic more and get more done. I seem to be much more organised with keeping track of my parts and ordering this time round, which is something that screwed me over royally at my first UK Champs, screwed me over slightly less the second time round and hopefully I (and the robot) should be screw free this time around.

First off was the continued work on the back panel (the one with the ghastly finish if you remember it) This time around I elected to do the machining jobs in an order that makes sense to the human brain and subsequently had a much better time of it.

Slots happened. Fits nicely. The inner aluminium bulkheads may end up not being used for weight reasons but its no real problem I can leave them out or easily make up some HDPE replacements.

Cutting down the material to make the front panel, again with a hacksaw due to not having anything better.
After cutting I milled the ends flat and straight. I was then able to sit them into the bulkheads.

All the frame now slots nicely together so it was time to start drilling and tapping some holes. M8 for the front piece as it is 5/8" thick and M5 for the rear finger joints as it has been milled down to 10mm in places for the motors to sit in.

Pretty chunky bolts for a pretty chunky frame. Feels solid as. Showing off the rear panel and its glorious  finish. I'm still happy as I managed to get it basically spot on from the cad drawing which is something I have never really been good at before.

Still needs a few holes drilled and some tapped but it is nearly done, w00t!

I just got the bar out of the old massacre to compare to the new ones. Pretty big difference. Longer and twice as wide I think. Also note the massive MOD 2 gear attached to the bar by 2 stainless M5 bolts. No bearings either! Fuck me I was so newbie it hurts to look at. And to think I wondered why it didn't work.

Here are some customary Pretend-O-Bot shots. One showing a 100mm "blue wheel" which is a pretty standard part in feathers. Small robot is small.

Ok a new day and I began getting the motors ready to be mounted in the frame. The side bulkheads needed 5mm pockets in them to fit the motors in. Yay designing. Also marking out the base plate to be cut.

Now for some srs bidness, the base plate. This is made out of 3.2mm Hardox which is a hardened wear plate steel, incredibly resilient and tough. Perfect for dealing with the rigours of combat. I generally favour plastics in robots, so this is my first time working with Hardox. I've never really worked that intensively with regular mild steel either.

Base marked out. I plonked the frame on top just to check I hadn't cocked up anywhere.

Base was cut out without any explosions or limbs lost. I expected it to be pretty ugly to work with but it was totally fine. I barely used any of the cutting discs. From recommendation from some of the high level builders I got the thin discs of about a millimetre or so. Seemed to cut it horrorshow like.  It did throw up some dirty powder stuff which melted the dip coating on one of my chibi G clamps and attached itself though, but no big deal.

Then I ground the burrs off the plate and the sheet I cut it from and put the frame over it to see if it was the right size, I was a little worried as I didn't have a big enough piece of Hardox left to redo it if had cattled it.

Luckily it was fine. And it its beginning to look a bit like a proper robot now. Which is worrying considering it really is anything but! I managed to drill and countersink the Hardox with no real difficulty. I used a centre drill first to get the hole started then opened it up a mm at at time using regular HSS drills. Countersinking was hard but then it turned out to be that my bit was blunt, a sharp 3 flute HSS countersink was gorgeous.

Marking out the bulkheads. Sharpie marking out ftw. ( lies, its not a proper sharpie, those are expensive)

Motor pockets done on one side, motors pushed in. Fits lovely. You may be wondering why, it's mostly to give as much internal space as possible in a tiny robot, and get the wheelbase to a certain size. The panels are quite complicated at one end because of the finger joints having the pockets in them. One of the fingers locks the motor into place, as you can see bellow.


I didn't feel like doing any more milling right then and there and things never go right when you force yourself into it so I took a break and dealt with the rest of the holes for the pulley to mount to the bar. I did two and then gave  up. Because M10 is fairly meaty to tap when you don't own a tap wrench. I'm more than a little ghetto I'll admit.

 Holes drilled, now on to tapping them. I found this pipe holder in the bins in the chemistry department at my old high school. Thought it looked about right for a pseudo tap wrench. I added one of my T handle allen keys to give a bit more leverage. Don't judge me too harshly. If it's stupid but it works it's not stupid and all that.

 Sorry for mangling your awesome pulley Ellis!

Quick break from Massacre, while searching for some nylon to make up a mounting jig I came across my old top panels from a previous robot of mine, Murphy's Law. (hence the M and L) One set is nylon but I didn't have the heart to chop it up just yet. The other set is chequer plate aluminium. FUN FACT: was the old armour plates from Steel Avenger from Robot Wars. This was on my first robot at the UK champs. It did not go well hahah. I like to think I've come a long way.

I liked Murphy's Law, however most of it's existence can be summed up with one picture.

Back to Massacre now.  The weapon ESC arrived. The one I wanted was back ordered to shit, and the second, third and fourth choices were likewise so I settled for this. Figures wise it's fine. Good for 160a cont and 200a burst. Just what I need. And yes before anybody asks its overspec for the motor.

By this point I was ready to get back in the milling saddle, so I was able to finish the motor pockets. The second side took less than half the time than the first and has a much much better finish. Yay learning!

Motor pocket #3 done. It fits well, which is nice to see. Its a truly wonderful feeling seeing an idea in CAD actually translate to the real world.

Motors mounted. Solid robot is very solid.

Then I got on and attached the wheels to see clearance and things. (and to Pretend-O-Bot some more ofc)

Got some components in there as well to see where things can go and if they fit which thankfully they do. I've taken to writing myself notes, that gearbox says "tighten me" and there is one written on the mill that says "clean me" I need to strip it and clean it, but no way am I doing that in the middle of hardcore building time.

Open Rangleboxen, much like an open sandwich, has its innards exposed. This differs from an open sandwich because it has to deal with 42,000 RPM and is made out of solid 6082 aluminium with cheese. Sorry that got odd. Never could get the hang of similes. Right anyway this is the latest iteration of my Rangleboxen weapon drive. Designed to be not total arse to make and to work and look solid and metal and cool. Time to cut stuff up!

Step 1: Giganto lump of aluminium.

Step 2: Just looking at this makes my arms sore. Can haz bandsaw plz

Step 3: there is no step 3 (or spoon for that matter)

Step 4: Mount block in the mill and go to town.

Step 5: Admire the shiny.

Step 6: Give up writing steps.

One face has been milled down to 8.5mm. The other side will get neatened up then taken down to 10mm because reasons.

Done for now. Obvs need to get the bearings and the motor mounted but still. it looks like a thing. Pulleys are on their way, as are belts.

Very heavy going I know, so congrats if you made it to the end. Your reward is this GIF.

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