HardWired II

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I see, thanks! This is the first I'll have ever used HDPE, so I'm still a bit unsure of its properties.
The worry at the minute is, say, Little Spinner catching it just right and spraying my batteries all over the floor - I know that's a worry for everyone but my lack of spares means it's just that little bit more important...

Might give it a go when the materials all get here, see how it holds up to a bit of crash testing!

[Ellis]

You will be amazed at how strong woodscrews into HDPE feels in your hands. It will feel completely immovable, because it is, for normal purposes. If you use big chunky screws, not too many but not too few, it will take some big hits to do major damage. And, if you're at the point of having batteries strewn across the arena, the opponent will have stopped hitting you. Gentlemen's agreement!

Also, pics as you build will help folks help you, regarding number and positions of screws and such.

[RogueTwoRobots]

And, if you're at the point of having batteries strewn across the arena, the opponent will have stopped hitting you.

I'm sure No Toy would disagree

Despite advice to the contrary (good advice though), I've edge tapped HDPE before with success. However instead of using a tap/die set, I just drilled a 5mm hole then drove the M6 bolts into the unthreaded hole and let it cut its own threads. The two downsides are that they aren't as dependable as threads in other materials and if you unscrew them/tighten them up a lot, they'll wear down pretty quickly too. But left to their own devices they're perfectly strong enough.

The other alternative if you don't want to use wood screws or L-angle brackets is to use push-fit brass inserts like these: http://www.ebay.co.uk/itm/M6-BRASS-I...item4cfe5c0c4a

Just drill an 8mm hole and hammer these in. It'll let you use bolts instead of wood screws and provides a good firm hold. If a spinner gets a good hit, it may well rip them out, but that is true of any fixing method if the spinner gets an ideal hit. You can always drill a smaller hole than 8mm and heat up the fittings so that they melt into the plastic (like the nut inserts on blue wheels).

And going back to your original question, M6 is a good size of fixing to use for edge-tapping, assuming your material isn't too thin. Obviously you can go for larger bolts if you want something stronger, but I certainly wouldn't go for anything less than M6 in featherweights.

[PJ-27]

I'm just using chunky wood screws to hold my HDPE. Can't see why that wouldn't be strong enough.

[Flag Captured]

I'd hope it wouldn't get to the point of having batteries smashed up, but it's nice to know that there's a gentleman's agreement!
It's 20mm HDPE I'm using, may bolt other things to it if it turns out that it's well under weight which I seriously doubt, but I'd hope that say, 8mm screws would be alright since that gives about 6mm either side of it? I might help support the 2/3mm stainless base using some L-angles, just so that the linear actuator (if it fits) doesn't pull it off by mistake or anything! My only worry is my slightly unusual design on the back end, it's not final but it's this weird sort of half-hexagonal shape, designed purely to give spinners a little less to bite on but can revert back to square if needs be. Would like it to look a bit more interesting though if I can, got some plans for that but I'll see how things go...

The plastic's apparently due this Monday, not yet sure about the drive/scoop though - whenever it's all here, expect plenty of pictures!

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Mini-Christmas time!

The Hardox scoop and drive system have now arrived, huge thanks to Mario for those! I'm rather amazed at how big the motors are - I knew Speed 900 motors and similar were a bit bigger than drill motors, but I didn't know they were THAT big! Must have spent a good 10 minutes just in awe of how huge they were - you can tell I'm new to this roboteering lark!

The Orange RX turned up the other day too, had minor problems with it to start with but kind of got it sorted, apart from the failsafing so that's still something that needs doing, but it seems straightforward as to what I have to do to get it working. Not touched that since Saturday!

Linear Actuators are also here, as mentioned in a previous post - I'm still playing around with the setups to see what I can fit in HardWired II under the weight limit for a micro extreme-budget 4-bar. I don't think I want a massive amount of lift on it, just enough to get underneath a machine.

Last but not least, I've got a great big sheet of 20mm HDPE to replace the aluminium shell, reason being that it was cheaper and easier for me to work with, and best of all I can reuse it on my other machines too. And I'll have a lot of spare for when the inevitable happens!

Pictures when I get back home - may even have HardWired II finished this week at this rate!

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I lied, pictures tomorrow. Just got in, and I'm way too tired.

Just as a question for tomorrow's design session- wood screws in 20mm HDPE, any sizes I should look for? And how much does the screw need to go into the HDPE to give a firm hold? I'd assume a longer screw would be better, but I thought I'd ask before I go drilling any holes!


Also, I got a huge sheet of 2mm HDPE too to make an armada of antweights, because why not. Expect a few of those soon-ish after this one's done!

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Here's the pictures of the parts from when they arrived the other day



Linear actuators just off to the side, there.

Basic layout of the machine here (pretend that the cardboard is >20mm HDPE)-





You may notice that there's a distinct lack of linear actuator in there, and that's because the wheels are only slightly larger than the height of the linacs themselves, and it'd be too much of a squeeze to get one in as well as having the lifting arm and all the other nice things that I'd need, so I've gone slightly boring and gotten rid for now. It's a real shame, but my engineering skills aren't really up to much so I'd rather go with something I know works than something that might fail.

Even worse, since I'm not entirely confident I could make the arm strong enough, there's the worry of me losing the ENTIRE front shovel if a spinner hits it right, which is just not a risk I can afford taking! Until then, it's super thick armour all the way, piling on the HDPE and so on. I am looking at drill-powered weaponry, even if it is just a gimmick because I am a bit conscious that some people think the 'push box' robots are boring. I've got some huge motors in there that are more than capable of putting on a good show, but I'll still look into it to see what I can do. Would like an arm on there, just in case I manage to get stuck on the arena wall...


Not really had too much time to work on it since the parts arrived, but before long I'll be sorting it all out!

[Niels - Team K.a.L.M.]

Nice, I've got the same motor setup lying next to me waiting to go in a second feather one day. Though it came with different/smaller wheels.

But why do you need your machine to run both ways? If the linak does it's job it will turn you back over.
I can understand the benefits of being able to drive both ways and srimech at a more oppertune moment but beggers can't be choosers.

[Flag Captured]

Thanks! And yeah, these are about 80mm I think, slightly larger than the old machine's but that's not necessarily a bad thing overall.

The reason it was to be invertible is more because the lifter was supposed to be like Storm II's, just as a compliment to the pushing power rather than a main weapon in its own right - the design would never have been able to self right properly, it would just lift robots off the ground so I could get under and push them about a bit. Not just that, but I'd need a secondary battery for it too, which is more weight and I'm not sure how close I'll be to the limit anyway with a heavy drive, heavy scoop and thick armour...

Not ruling it out just yet, but it might be something more for the second version of this machine. Was toying with the idea of a small spinner instead to rack up a few damage points in my favour but that's probably just going to stay an idea at this point.

[mrsam]

Nice looking bits, I'm assuming the work of a certain Mario?

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They are indeed! Very nicely done too. The drives are similar to other ones I've seen, just welded to an angled piece of steel

The only other pieces to the machine which aren't pictured here are the ESCs (TZ85As) Rx (Orange R620) and battery (5000mAh 30C, 4S) which are all fairly standard as far as parts go. They're all in HardWired I and I've not had chance to take them all out yet!

[Flag Captured]

Still not properly started the build as I'm trying to find a decent baseplate. Call it a bit of a bodge if you want, but I'm going to attempt to cut down a 20mm HDPE baseplate to about 5mm and use that instead, or alternatively I'll get a piece of stainless steel or something to make it work. Issue at the minute is getting something strong enough to bolt/weld this drive system and other parts to, whilst also keeping it workable with basic tools (cordless drill, hacksaw, angle grinder) that's also cheap and readily available. I know that's a bit optimistic, but it's what I'm needing to do at this point!

Other than that, I'm now designing an ant and beetleweight made out of leftover HDPE from this, the beetle's going to be a wedge shaped drum spinner (already got some of the structural parts for that after a brief practice at cutting the 20mm HDPE) and the ant I'm not really sure of yet, but I've got a basic 4wd wedge chassis made from 2mm HDPE and bits of dishwasher. Basic idea of that one is that it's cheap to fix up, and would probably get very badly damaged pretty easily. Servo drive most likely and dishwasher-mystery-metal wheels with a rubber band on them for traction, and again would get pretty badly wrecked. Would most definitely look fantastic whilst getting wrecked though!

[Ellis]

A 50cm*50cm 5mm thick sheet of HDPE is 8 quid from Directplastics. How would you cut the 20mm stuff down? I can't think of any half accurate way with hand tools. Potentially very material-inefficient, too, assuming it could be done at all; the cost of material lost in doing it is probably about the same as the cost of some 5mm sheet.

If you can get some stainless sheet, even 1mm thick will make for a sturdier base than 5mm HDPE. Of course, it is harder to work. If you have a hacksaw, patience, and suitable drill bits you're there.

A source of thin steel in huge amounts often for free is kitchen white goods.

[Flag Captured]

That's not too bad, thinking about it... And I'm not really that sure to be honest, it was just an idea. Was going to cut a chassis shape and cut it down slowly with a sander. Probably going to go for the steel route though I think! Having such a powerful drive, I'd hate for it to warp the plastic or whatever over time... I do have a friend who's got some scrap stainless, but I have no idea on the thickness, so I might check that! Probably buy some cobalt drill bits and see if that helps things!

I do have a couple of dishwasher sides spare, never used them because they seemed to bend a tad bit too easy... Might give them another go though!