Get Shrekt

Been a long time since I last posted on here, but I thought I’d share what I’m up to right now. Any of you on Facebook will probably have seen my Featherweight spinner “Get Shrekt”, it’s a big green thing with an Inertia disc that likes to throw other feathers into roofs, which, came as a surprise to me!. Since it first appeared at Maidstone it’s been sitting in my garage unloved, so with Manchester just on the horizon I thought I’d give it some tlc and bring it along.
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Shrekt was finished in a rush for Maidstone and, as a result it had some things that were a bit suspect/not as good as they should have been, so I’ve been going through it and fixing the things that need fixing. I decided that the majority of the chassis was probably fine to keep, however the side panels needed to be redone, so they were the first thing on my list, they’re 25mm hdpe and also act as the mounts for the drive motors.
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Next up was the mount for the brushless motor that spins the disc, because I was in a rush last time I used the cheapo Aluminium mount that came with the motor. On a particularly big impact it twisted something rotten, so I needed something more robust.
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Enter this little fellow on the right (old mount on the left), it’s made from 5mm 6082 Aluminium and is substantially stronger than the old one. Hopefully this will allow Shrekt to give big hits without bending out of shape. The next issue was something altogether worse, I discovered at Maidstone that the weapon shaft had been spinning in the bores, wearing away at the material and making the belt lose tension. So to fix this I made up a shaft lock, that threads onto the end of the shaft and the bolts into the bulkhead. This both stops the shaft spinning and acts as a mount to keep the shaft in place. It’s made from 15mm 6082 Aluminium, that I cut with a hacksaw then drilled using my new pillar drill, then tapped it to m12. I can’t tell you how useful the pillar drill has been for making parts like this, I couldn’t do them without it.

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Thats all for now, but I’ll try to remember to post the rest of the upgrades as and when they happen.



Cheers,
Sam

Ooooooohhhhhh.... its back! :D I look forwards to seeing this at Manchester if it makes it.

great, I may have to face this at me first event =P Speaking of which where is the entry forms for Manchester ?

It is here:

http://www.emailmeform.com/builder/f...ZLgQK6073tYFlz

Done a bit more on “Shrekt” over the past couple of days, mainly beefing up the chassis. Previously it was held together with screw In threaded inserts which I just never trusted, so these have been replaced with barrel nuts as I’ve used them for years and never had a failure. I’ve also made a start on the wheel guards, these protect the wheels but also help to minimise the gyro when turning.

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More updates to follow

Cheers

Looks like it is coming together nicely - curious though as to how the guards help with the gyro effect?

They help a couple of ways tbh, firstly they make the robot wider and secondly, when Shrekt had exposed wheels there was nothing but the wheels to lever against when turning, hence the amount of gyro. The wheel guards basically act as a stop point for when the robot does gyro.

I love your robots. Is it ok to ask how you cut your HDPE?

I tend to cut all my plastic now with a hand held panel saw then clean it up with a rasp and file.

Oh cool. Cheers for replying.

Done a bit more work on Shrekt, namely tidying up the internals and making sure they’re as protected from shock as possible. I’ve also put the front forks back on, they’re probably not the most functional things but they look pretty cool. At this point the robot isn’t far off finished, and I have plenty of time until Manchester, not used to being ready this far in advance!

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Cheers

So I had a few days off from work and was able to get Shrekt finished and ready for Manchester. It’s not as perfect as I’d like but for something basically handmade I won’t complain too much. Looking forward to seeing what it can really do!

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Haven’t updated this in a while, Get Shrekt has had a major overhaul the past couple of weeks.

So Insomnia was a great event for Shrekt, it won all of its qualifiers by knockout and managed to get all the way into the top 8! Not bad for a first event. However it did show up some flaws with the design that I couldn’t really ignore and with Cheltenham on the horizon I thought I’d fix some of the more major stuff and bring it along.

First up was the weapon bulkheads, when I built Shrekt initially I didn’t really pay much attention to the angle at which the wedge fed stuff into the disc, or how long said wedge should be. As it turns out, having a super shallow, super long wedge isn’t great for consistent bite. To fix this I completely re-made both bulkheads with a much steeper wedge mount, to get the wedge almost parallel with where the disc tooth comes around. This should result in much bigger hits more consistently.
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Next up, addressing the slight issue that in every fight At Insomnia, Shrekt bent the shaft for the weapon motor. I’ve put this down to 2 things, the shaft material and the lack of support between the back of the pulley and where the shaft goes through the bulkhead. I made a new Grade 5 Titanium shaft and also added a bearing to the bulkhead to hopefully add some extra support.

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Decided that the bodged, fairly weedy wheelguards should probably go too. They’ve been fine but whilst I was fixing everything else I figured I’d do that as well. The old ones were a mix of 15 and 20mm hdpe, the new wheelguards are all 20mm with 35mm thick bar at the back, much more substantial.

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All that was left to do now was some new top covers and mounting the wedge. I had planned a new wedge but for a spinner heavy live event I didn’t see much point I risking getting it damaged. I’ve just cut the old wedgelet down by about 45mm and resharpened it.

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Apologies for the slight word vomit, Lots to talk about.

Shrekt will be at Extreme Robots Cheltenham this Sunday so I’ll hopefully see some of you there!

Cheers, Sam

Do you drill everything with a cordless drill? It's always so accurate!!

I use my drill press for most things nowadays, best tool I ever invested in. For stuff that I can’t put on the drill pres like the wedge mounts and base of the bulkheads etc I use a cordless drill.

I second the use of a drill press. I just have one for holding a standard corded drill in, cost about £15 but worth every penny.

*Blows away cobwebs*

Been a long time since I posted here, having just returned from a very successful Cheltenham event I thought I’d give a quick update of where Get Shrekt is currently and future plans.

This year has been up and down for Get Shrekt, whether it due to age or my oversights there has always been one problem with it or another. I went into the Featherweight Champs this year feeling pretty confident, the machine had been running great at it last 2 events and it was hitting harder than ever before. It’s run at the event was *fine*, it won its heat and made it to the top 16 but crashed out after that, and the whole event it was plagued with belt tension issues and seemingly it was now too powerful for the bolts holding the disc to the pulley, as these were shearing on particularly big impacts. Honestly post champs I was ready to retire the old boy and focus on my new Featherweight, but I’d already planned to go to Cheltenham so decided to give it some tlc and see if the issues could be fixed.

First up was the issue of shearing the bolts in the pulley, Shrekt has been using 4 m6 countersink bolts since I first built it however these were now not up to the hits it delivers these days. I purchased a milling machine this year so put that to use drilling out the holes in the disc and pulley to 8mm, and adding counterbores for the new cap head bolts. This should stop any bending/shearing but I’d find out at Cheltenham.

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Next on the list was the issue with belt tension, I use a smooth pulley on the weapon (toothed on the motor) to allow it to slip, unfortunately if the belt isn’t super tight to begin with then any belt stretch/wear can cause it to slip instead of spinning the weapon. At the champs I resorted to covering the pulley in tape, which worked but I wanted a more permanent solution. A quick and dirty belt tensioner was made up, literally just some bearings on an m6 bolt and whilst the belt was initially very tight, it would slacken off over time.

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A quick systems check and it was all ready for Cheltenham, unfortunately however I could only make the Sunday due to work commitments. Happy to report that the improvements worked perfectly, Get Shrekt dominated in both Sunday melees and scored some of the biggest hits its ever got. The disc span up first time every time and no bending or shearing of the disc bolts. One issue is that the extra belt tension does seem to be drawing more current, so the tiny (1.8ah) lipos we’re struggling to do a 3 minute fight. This version of Get Shrekt will be retiring at the end of the year, so this was a great way to send it off if I can’t make Robodojo in December.

Apologies for the word vomit, I’ll leave some pictures of some of the damage and try and not leave it another year to post an update.

cheers, Sam

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hmmmm i wonder what be replacing it..............

That is an impressive set of damage photos!

It's great to see all the little incremental changes you've made to make GS the monster it is today. Hopefully see you at Robodojo in a couple of weeks for its swansong and looking forward to whatever (presumably ogre-themed?) robot machine you come up with next!