We are quite lucky, in that a friend of my dad's owns a workshop from which he runs his business of paint stripping. In this workshop there is a big MIG welder, pillar drill, a big disc cutter, an electric hacksaw and a reasonable amount of space. This is where we build the chassis as it has the required tools, all the electronics and small stuff is done at home.

We soon began construction of the proper chassis and started with base frame, this sits on top of the wooden base board. You may be thinking "hmmm, wood and the flame pit, yes" but wood has a lot going for it: its strong, light, cheap, is easy to work with and has some shock absorbing properties. We have a sheet of 3mm aluminium plate that will go on the bottom of the base board to fireproof it and protect us from some axes if we are turned over. Anyway, we constructed the chassis using 1inch steel box section on the base board to make sure everything was where it should be. After lots of measurements, ensuring was square and properly lined up, the finished the chassis was thrown still hot onto the workshop floor….

At home we cut the chassis into two, this allowed us to easily identify exactly where each half was distorted. Using a small oxy-propane torch we heated the bent areas to cherry red and levered it straight with the aid of a table top as a definite flat. The two halves were later welded back together and a new base board fitted, and hey presto-a flat chassis.

All load bearing areas such as the motor mounts, lifting flap mounts and the axe pivot mounts are being built from 1 inch steel box section, the majority of the upper chassis will be built using 1/2 steel box section and 1/2 steel tubing.

Basically, the straight parts of the upper chassis are built using the 1/2 inch box, while any curves are built from 1/2 tubing. For the curves we bent a plastic rod to the shape desired, then tried to find something the tubing could be bent around. For a lot of the curves, we found that a large steel drum was a close match. To bend it, one end of the tubing was clamped to the drum and starting at the clamp, the tubing was heated while pressure was applied to the other end. When hot enough the tubing would give to the shape of the drum. This was repeated along the desired length and left a reasonable curve, as long as the tubing is held tight against the drum.

At this point, the upper chassis is partially completed, more ribs and braces need to be added as well as the weapon mounts, when we have worked out what and where we need it. The robot is currently has the motors in the finished mounts, with the speed controllers, radio gear and two huge 38ah batteries temporarily fixed down so that I can practise (play) with it. It will soon be stripped down to build the weapons.

According to our bathroom scales, the present robot weighs 60kg, this leaves only 20kg for the rest of the chassis, armour and weapons. This weight can easily be reduced by swapping the 38ah batteries (15kg each!) for four 7ah batteries (2.5kg each). These batteries will be fine for the drive, but will require an extra battery for the weapons. If at the end we are over weight, the PLY block-board base board will be the first thing to go (weighs lots) and replaced with 1/4" PLY which is much lighter, (not blocks of PLY in a wooden sandwich).

Here are some piccies of the basic chassis, these were taken a while ago and are not up to date with the chassis we have now. Those without wonky eyesight will probably realise that on the rear view picture the piece of tubing for the rear impact bar is severely skew-whiff, This has now been straightened.