Wheel guards/side rails look great.
In addition to looking nice and losing a few grams it should also make it harder for verts to get bite.
Win win win 
The chamfer looks so slick, how do you go about that by hand?
Missed the Q @Joe it’s just done with a 45 degree chamfer bit in my router. Forming bits open up a huge amount of possibilities for funky shapes as the bearing just follows whatever the contour is. You can leave it super shallow for a cheeky debur or edge break.
Printed templates and this is my new best friend. It’s jolly messy however and I think I have strained my marriage somewhat with the little plastic slivers making their wicked way throughout the house.
When life gives you lemons etc. I did the classic yellow dylon bath for the printed nylon parts and it came out pretty well again. I’m looking forward to doing a robot that isn’t yellow so my hands don’t look quite so jaundiced/nicotine stained after fishing them out.
I started doing final assembly at this point, putting in the proper loom and mounting up the end stop micro switch. The axe mechanism goes together and comes apart really well. Traditionally I don’t have to touch it so by the law of sod I’ll have to strip and rebuild every fight.
Cleaned up the hardox forks as well, gave them a brush off and kissed the bore with a countersink.
For the first time ever ML is sporting some edge. Ground the axe head so it’s at least sharp. Still not deluded enough to think it’ll do anything but it at least looks like it’s trying.
The weapon subassembly is looking mega if I do say so myself. Super bitsy and it packs a pretty impressive punch.
Had to skim down the boss of the pinions. I have a set being machined properly but I had to ghetto it in the interim as time is getting tight.
Sitting pretty at about 1400g minus lid. It’s the heaviest, widest and hopefully the best MotherLoader built to date. Roll on Brawl!
Pretty angry on the axe and the drive ain’t half bad.
3 Likes
Think you need longer forks haha
Brawl has come and gone and it was a super time. I know here on this forum I’m preaching to the converted but I’m always hugely impressed by BBB and the care and attention that goes into their events. Not only is it legitimate and awesome competitive scene if takes excellent care of the human element which is wonderful.
So this was it for MotherLoader(s) this was the last chance for redemption, success and warm fuzzy feelings. The big question on nobodies lips, did it achieve any of that?
Answer: Kinda!?
All (some) will become clearer (not) by the end of this ramble. So let’s start at the beginning of the end. I had a mad little dash at the last minute to get it all together. Nothing too hectic but it was a good couple hours every day in the week proceeding the event
I got it slipping under the weight limit. I had a bit of a nail biting five minutes as the first weigh up it was 1503g. That was with the sharp edge and locking bar so luckily it could fall under with those items put aside.
I also decided to grow up and put a little effort into my sharp edge protection now that the axe actually has a little edge to it. It’s a contoured chunk of ABS which locks to the hardox with a couple of 6mm magnets glued into it.
As is customary I snapped a picture with the shell of the prior version which was also coming with me to Bristol as a stop on it’s way to it’s new home. You can see T34 is a touch wider and fractionally longer thanks to the forks. The chassis profile is identical all the way back to MK1. .
My first fight was against Digestive and The Mangler. Two polar approaches for naming on show here. I was a little on the back foot to be the only non spinner but it was quite nice in a way. What a way to put the robot through it’s paces! Cards on the table, I wasn’t too worried about Mangler as while it had the potential to get to the thinnest armour I felt confident I could avoid getting into bad situations and I could overpower them from a drive point of view. Digestive was the real worry.
I was correct to be worried. Verts get a fearsome reputation and that’s one I feed into myself but not all are created equal. The speed of the drive and the sheer anger in the weapon meant I could not keep up in any meaningful way and just became a bit of a chew toy.
I take a slim moral victory in the fact that I was able to keep soaking up some really nasty hits without really suffering. The lights stayed on and everyone was most certainly still home. The HDPE stood up well and I’m glad I went for 10mm everywhere.
The worst but was arguably the baseplate which had been hole punched and had a substantial trench carved just shy of the important bits. Taking it off the robot I found it was badly warped. Cutting the smushed parts away seemed to remove the internal stress in the part and let it go from Pringle shaped to flat-ish. I was a little miffed at the track had come off as I was completely willing to keep going. I think it was just impact related though I’m not ruling out stretch.
I had a cup of tea and a scotch egg to steel my reserve and got on with mundane activities like charging batteries and bemoaning my now slightly wonky (ier) chassis.
I was then told I was fighting Tsukikage which was a bit of a downer for me. I do not do well with control fights. This robot was 4wd with lots of forks and pokey bits to get hung up on. I wasn’t realistically able to overpower him nor out drive him. I think potentially I had the speed advantage but not the wherewithal to make use of it.
We were a pretty even matchup with no quarter given either way in the battle for control. Meg was going absolutely buckwild with the axe which caused the front to jump a little on a miss but I think ultimately turned the tide as we landed more hits than we didn’t.
A loss and a win was a pretty good place to be, until I found out I’d drawn Andy.
I always tend to do a quick function check when I’m back to my table after a fight. Just blipping drive backwards and forward and seeing the axe twitch is enough for me. I did this post Tsukikage and all was well so I slapped the battery on charge. A little while later I picked up the robot to show or demonstrate something and found the right hand track had locked up completely and would not be back driven. Odd. I plugged the battery in to check further and was immediately greeted by thick white smoke and an unpleasant smell. It was like being back in school.
I just went head down and swapped the whole unit out. Thankfully ML is pretty easy to chop and change out components so it was a pretty easy fix. It was only later trying to run through the steps in my head did I hammer out a working theory.
-intensive driving fight causing a bit more heat than I’m used to
-scratch that, a LOT more heat. Enough to soften the epoxy of the windings.
-when it’s still hot it works just fine. Once it has time to cool, say the time it takes to charge a battery it has cooled and the windings have now set so they’re touching with no coating left on them.
Motor locks up, just waiting for a drop of current and then boom. Toasty.
I am willing to entertain other theories but that one seems to fit. Glad I checked as I would have looked like a monumental tit. Swaggering up to the arena, turning my robot on and having it immediately let out a sad cloud of smoke and stop working. Bet that would have gone down well with the marshals.
ANYWAY,
The Propane was pretty short and brutal with me failing to get any footing once again and just resolving myself to tanking hits and trying to outlast Andy in the hope he broke his hardened fist on my wobbly yellow face. Unfortunately the repeated abuse knocked the track off but I was in a position to wiggle onward, soaking up a few more hits before a nasty hit to the rear took out the link door, power light and link. Smashing the rear panel in the process. Dead in the water, it counted as a tap out but it was lost either way I just saved having to count to ten.
So that’s it. Finished as I started. The first version was what really got me back in to robots. I made something pretty rubbish but functional which a bit of flair and I have been chasing that ever since. I made a lot of mistakes and errors trying to recreate the purity and effectiveness of a weaponless wedge.
MotherLoader-T34 was designed to work. It was supposed to be brutal and hardy and be controllable. I took every step I could to make it reliable and drivable and honestly, this was pretty successful. It wasn’t the nicest looking or the most interesting thing I have built but I figured I had to take a step back. If I keep failing to make interesting and clever work for me, dumbing down to stay in my lane is a valid strategy.
I’m happy it got one win, with my low bar for success that’s pretty good going. At least over the last two years I haven’t gone backwards and that is no mean feat.
Happily I think for all concerned I’m still set on this being the Last Guy for the foreseeable. I’m probably going to keep this in broadly fighting spec (new baseplate, cut the mushed bits off the armour) for whiteboards should the opportunity present itself.
More photos can be found here: Log in to Facebook | Facebook
I’m looking forward to making something different.
10 Likes
Top writeup Harry, and regardless of performance I love the robot. Looks lovely and really stands out in the sea of verts. 
This is completely ready to pass POM right?
Hard Nips has been rejigged to make sense and be the best it can be. I have thrown yet more sheet metal at my problem, coupled with prints and some tenuous engineering practices.
At least it’s really simple electrically now with the repeat dual esc bring 90% of the circuit done before I start.
Here is the prototype sporting BZ John Deere colours (John zoom? Boom Deere?) to show what I’m working towards
Lots of bits still to do (obviously) but this shows sor of the actuator nonsense and layout.
7 Likes
Absolutely wild as always Harry. Your build log posts are always ones I enjoy
Fell way too short for BBB, gutting all around but clawing back some progress for next year!
My horrible part that would make any decent designer cringe was blipped out by china. It’s a redrawn actuator endcap machined from 7075 and black anodised. This rides on a flanged plastic bushes and is retained by an M3 bolt & washer. There is a phat flanged bushing making it smooth and supple in motion. Stupidly this could potentially be pushed outward with the actuator extension so a retaining screw will be added as a total afterthought. Amateur hour starts now.
My lasercutting turned up today so I have been pushing the chassis around and getting a feel for it.
This is just a lot of the same but different angles. You can see how the drive is setup better here. There are no retaining clips on any of the bulkhead mounted electronics yet.
Seeing my forkie pokie bits in reality I am underwhelmed by them. I sort of want to go for a shallow razer-esque wedge or something thicker in TPU. The pivot works pretty well though.
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Slopping my way through a little more progress.
Second set of wheels had their tyres cast and I can highlight my slightly silly method of quick swapping wheels over. The hubs have notches in them to accommodate a low profile cap head jammed in the grub screw hole on the pulley boss. I could use all 3 as they’re nicely spaced 120 degrees but I don’t feel it’s necessary.
I could have just printed a GT2 pulley as part of the wheel but I never seem to get the profile quite right and these were a couple of pounds and almost completely off the shelf. John Williams bored one side for a 5*11 bearing.
I also finished off the actuator at this point, assembled the shortened unit with custom trunnion end cap and am pretty happy with the weight of it all. Considering the stock weight was in excess of 700g it’s quite a dramatic improvement. I feel I can winkle out a few grams but will be fast approaching diminishing returns.
I plopped in some of the nylon bushes from ranglebox into the claw pivot so I could wang it all together and make a proper facsimile of the robot. These just push though the Alu and are trimmed to length with a Stanley knife.
I cut and drilled my drive shafts and slopped the internal core of the robot together for a bit of a jolly. There are parts that desperately need reprinting and obviously I need to fold the arse plate and claw but it’s taking shape remarkably well.
While the outside armour is integral to the drive (singly supported pulleys are An Sad) I could just about push it towards function with the baseplate template and the printed widgets.
I was really looking forward to seeing it hobble under power and try out the Repeat Dual ESC finally.
Little bit of a damp squib because of the patched and unsupported nature of the belt stages but I’m loving the potential for low speed control! Just wish it had on board mixing!
6 Likes
That is coming together beautifully! It’s a shame you couldn’t make it to summer showdown, but it was definitely the right call. No sense in rushing a bot if its not ready
1 Like
Yeah I mean it’s a habit I’ve become more comfortable with the longer I’m in the sport. Less inclined to turn up with patched rubbish.
I had a spare couple of minutes at work (read: I made sure I had a spare ten minutes and a free machine) so could quietly fold a couple bits.
The beak looks pretty good all buttoned up! It has a printed bush that will sit at the pivot point or the arm and hold the ‘wide’ end together.
Shoved the lil guy on the scale and honestly it’s heavy but not impossible. I’ll likely have to get creative but I can do at least 75% of what I want which is better than nothing.
3 Likes
Hear you about being less inclined to turn up with rushed patched up bodges.
I hate being unprepared or turning up to an event with a bot I don’t have faith in.
Progress is looking 
as usual Harry! - as always this thread is one of the ones I’m always stoked to read updates on.
Ps I’m loving the drive set up 
I also hate turning up to an event with an unfinished or barely finished robot, but it’s the only way I ever finish anything so 
That’s looking absolutely lush, the folded metal frame is the shizzle. 