new Roboteer asking for building tips and so on(First robot)

The victors do not have a BEC (battery eliminator circuit). You will therefore having two options, use a receiver battery pack

http://www.technobotsonline.com/ni-mh-4 ... 00mah.html

or use a seperate BEC

http://www.technobotsonline.com/smartbec-5v-1.25a.html

I seen Hardox that have numbers 300 to 600 is it like grades for titanium?

I belive that number is the Brinell hardness.

Ok so the numbers are the Brinell hardness so let's say i get hardox 600 can i still use a 230mm angle grinder and cobalt drills and does the weight change?

yes, yes (it will be more of a bugger to drill and cut) and no.

You may struggle to find thin enough hardox 600. Can't remember what the min thickness is but i remember it being thicker than the 4mm hardox 400

In a featherweight if you angle your armour 4mm Hardox 400 will be more than enough.

Yes I agree 4mm hardox is plenty in a featherweight. Many of the parts you need to build a new machine can also be found on our website www.robochallenge.co.uk

I like to ask about wheels and drive shafts, first i know that wheels have a plain or a nut. But what i like to ask is how do you attach wheels that have no plain or a nut? and how you attach the shaft to the chassis.

ok I'm not explaining this very well, basically what I'm asking for is the number of ways to assemble the drive.

way i prefere to do it, have a fixed shaft, which can just be a bolt which is just fixed to a bulk head or something, and get a robochallenge wheel with bearings in the actual wheel hub then it just spins freely on the bolt and a pully or sprocket can be bolted to the wheel to give it drive

or have it, so bearings are mounted in a bulk head which would then allow the axle to spin instead of it being fixed with wheels etc being secured to the shaft

Ok so how do you fit the bearing in the wheel hub? and while I'm at it how thick does the steel bar's for the chassis you recommend 16x16mm or something like 20X20mm.