Help with choosing parts for a first robot, please.

[Rapidrory]

Yeah, an HDPE wedge would likely get fairly blunt in just one fight.. However a simple way to do it may just be to make an HDPE wedge and then bolt a bit of sheet steel to the end of it to give it some strength. Something like 2mm mild steel sheet would probably work fine for non- spinner combat, as the HDPE behind it will stop it bending, and the steel on top will stop it going blunt.

[dotDominic]

Ok, thanks. Was a bit worried about this since I have no metal cutting tools/equipment. Might be able to scavenge something usable.

[RogueTwoRobots]

If it's just a flat piece of steel you'd be needing, once you get some dimensions give me a shout. Got some scraps of 2mm and 3mm kicking about the shed so may be able to cut you something to size.

[dotDominic]

That would be fantastic, thanks so much! Not sure about the dimensions yet, but I'll try and get something planned out. It would be more like 2 flat pieces if that's ok, as I plan for my robot to have a front and a rear wedge, but if it's not too much trouble and you're just using up scraps that would be really good of you. Thanks!

Can I PM you at a later date about dimensions and payment and things?

[Flag Captured]

Yeah, an HDPE wedge would likely get fairly blunt in just one fight..

Overdrive had a HDPE wedge.

https://www.youtube.com/watch?v=BOs1x9v4Hwg

The moral of the story is make sure the HDPE doesn't flex into your spinning weapon...

But yeah, steel would be ideal if you can find a piece to fit, I'd definitely recommend that.

[RogueTwoRobots]

Yeah, not a problem. Two flat pieces is fine too, just didn't want to offer anything requiring welding or anything more complex, as the precision can sometimes be called into question

[dotDominic]

Haha, that's ok. 2 flat pieces would be superb, thanks very much!

[dotDominic]

Ok, so I was looking at these on Ranglebox.com: http://ranglebox.com/mechanical-products/

Just wondering if this is needed to join HDPE together, or can HDPE sheets be bolted directly to each other, without any joining elements? If it is necessary, would it be the M4 or M6 threaded bar I'd need?
And also, how would one go about cutting the bar to size? Is an angle grinder necessary?
I know this was mentioned on this thread by Flag Captured a while ago now - sorry for not asking about it sooner!

I'm a little bit away actually building much at the moment as I'm still having problems with the drill chucks from hell. None of my local shops had torx screwdrivers, but I'm going to a hobby shop in another town tomorrow so hopefully I can get this sorted!

[harry hills]

HDPE is too soft to hold a thread. Use the m6 ranglebox. Use a hacksaw. Don't grind aluminum.

[Max]

I've found HDPE can kinda hold a thread, I tend to just drill the appropriate tapping size hole then wind the bolt in with a cordless drill and it cuts it own thread that will last a fairly long time as long as it is not in full combat.
Also a lot of people just use ordinary wood screws to hold the panels together and as long as they are not remove and put back in too many times they shoudo hood just fine.

[maddox10]

HDPE doesn't hold thread.
Ranglebox is just easy. Other solution is to use L angle and nut and bolt.

I have seen other solutions , like IKEA Tnuts or other fibreboard/MDF connection methodes.

[Eventorizon]

Ok, so I was looking at these on Ranglebox.com: http://ranglebox.com/mechanical-products/

Just wondering if this is needed to join HDPE together, or can HDPE sheets be bolted directly to each other, without any joining elements? If it is necessary, would it be the M4 or M6 threaded bar I'd need?
And also, how would one go about cutting the bar to size? Is an angle grinder necessary?
I know this was mentioned on this thread by Flag Captured a while ago now - sorry for not asking about it sooner!

I'm a little bit away actually building much at the moment as I'm still having problems with the drill chucks from hell. None of my local shops had torx screwdrivers, but I'm going to a hobby shop in another town tomorrow so hopefully I can get this sorted!

Rangle Box is just Aluminium so you can cut it with a hacksaw with no problem and then file the ends neat, even Wet 'n' Dry sandpaper would do, its much softer than steel.

HDPE can hold a thread, it has been done but given that tapping it requires a Tap and a turning tool and a drill of a specialist size, ege 6.8mm for an M8 bolt, I would suggest using barrel nuts for some parts too. Then you just need a drill and 2 normal drill bits, and M8 for the bolt to go in and a M12 for the barrel nut for example. A combination of that and Ranglebox will allow you to deal with almost any joining situation.

The M6 Ranglebox is aimed at the Featherweight class where as the M4 can be used strategically in feather but I would say lends itself better to the beetleweight class.

[dotDominic]

Right, so I'll use a combination of M6 Ranglebox and bolts with barrel nuts.

Thanks very much for the responses!

[Flag Captured]

Both Ellis and Sam (Tormenta 2/Rango, Hatchet respectively) use barrel nuts in HDPE and swear by them. If you install them right, they're excellently strong! And as for the Ranglebox threaded rod, again used right it's really nice stuff. Think it held Tormenta 3 together this year, and I think Mario's used it on (Nebelwerfer?) to nice effect. Really handy!

[Ellis]

Everything except the wedge on Tormenta 3 is held together with M6 Threaded Bar and barrelnuts.