Hoo boy, here we go again.

So after a long debate (with myself more than anyone else), I'm going to attempt to build a featherweight robot, just on the basis of cost constraints, that and it'd be my birthday present that I'll be giving to myself, but it's going to need a lot of thought, and quite a few questions, which I hope you guys would help me out on.

So, the name of the robot will be called Ratatoskr, in kin to the messenger of Yggdrasil of Norse mythology. Two wheeled, drill motor driven and more than likely, HDPE chopping board/sheet in every way... possibly. Maybe. Who knows.

Things I know would be in the final design/product as it were...
- The motors will definitely be drill motors. They're either going to be second hand, or super cheap from Argos, or Homebase or something similar shop wise.
- The baseplate/chassis will be entirely made out of HDPE. No need for welding, just a lot of drilling.
- My best bet for ESCs would be either getting them from Ranglebox, or from Rory Mangle's site, as his FeatherTwo ESC looks like it would be a nice fit for the robot.
- For the controller, I'd love to get a Pistol grip controller. I'd have to do a little more research into that but my good friend knows of an RC place that could help.
- Tab and Slot. It'll be easier to replace wrecked pieces of armour or chassis, cut out new pieces and screw them in.

Things I'm a little sceptical about:
- The weapon. I'm not sure if I should go with my original idea of a vertical spinning blade, similar to the famous Pussycat Series 4 version, or make it an axe similar to Hatchet.
- Armour. I'm honestly not sure if I should splash out on getting some Hardox or mild steel sheet for side and front armour, or just make it entirely HDPE. I'm on the fence about it because I could always start off with HDPE then move on to metals.
- Batteries. I'm not sure if I should go 6 cell or 4 cell, and a decent charger to go with it all.

Questions about all of this, and fingers crossed when I get the chance to make a video...

Would 10mm HDPE be enough to cover all bases of the chassis? Or will I need to go a little thicker? And what's the best place to buy sheets of HDPE? Or should I just buy big ol' chopping boards and cut them down to size instead?

What would be the best screws, nuts and bolts for this kind of thing? As I need the base to be flat to the ground as much as possible, so the flatter, the better. And how thick do these things need to be to withstand heavy hits from spinning weapons and general wear and tear?

Wiring. How thick should the wires be to withstand the current going through it?

For the weapons, will I need bearings or bushings, depending on what I go with? And if so, what would be the best bet to get them from for a decent price?

And whenever possible, fingers crossed, I'll be able to post a video on some design work of it all, as I have been using cardboard from old soda drink boxes to cut up and use for design purposes. Not exactly prototyping, but to form shapes and such, so hopefully I'll be able to explain more with that.

If anything is confusing, then just give me a nudge, and I'll try to explain it as best as I can. Writing sentences isn't exactly my strongest aspect.