Geoff, the A-frame is actualy a bottom part that connects the drive to the weapon, the top is bolted on with sufficiently strong bolts.

The axle of the disk is welded in the bottom frame and centred and bolted in the top frame.
To the back of that A frame, a steel spine is welded and used to bolt on the weapon gearbox and the drivetrain main brace-steel angle- is welded on that.

The weapon gearbox ,what was a solid billet of ali, acts as a stiffner for the spine between A frame and Drivetrain, not unlike the engine in the better hi-power motorbikes.

The armor, constructed according to Adrians wishes is bolted, with a lot 8.8 grade bolts, to the bottom A frame and the steel angle what forms the main brace of the drivetrain. The top plate of the armor can be removed seperatly

For ease of maintenance the weapon gearbox can be removed without undoing the bottom and/or side armor.

All welds TIG welded, and all the bolts used to connect top and bottom A frame, as well the weapon gearbox are 10.9 quality.

Adrian, the power of this thing is so, I wont try to smash something without me far far away with the remote in my hands. The tests at my workbench scared the bejeeves out of me. And thats just spin-up and down.