Black Pig Too

[brock]

   Today we have been jigging. It's fairly important to get all the grubby bits in the right order and somewhere near the right place as the chassis rails will be built around them. Pro chassis shops have huge and complex ways of doing this, Andy Robinson, for instance, has a surface table that must be five by ten in feet and well over a foot thick and being cast iron is pretty stable. Into the top of this are machined "T" slots into which all manner of stuff can be bolted to hold everything where it should be. We, of course, make do with something a bit less elaborate. A fourteen foot length of R.U.B. with adjustable legs on it. Last night I zeroed the surface to within a millimetre over it's length and tonight I started adding the bits that matter.
   First on is a small cradle that holds the torsion beam at the right height and square to the centre line. From this point I can then set out the wheelbase, all the dimensions are taken from drawings I did before ordering the tube. having set that out the rear axle cradle is tacked on, leveled, braced and welded. A quick coat of primer on the top surface of the beam to make it easier to see the markings and we are set.

[brock]

   A passing big fella is collared to lift in the axle, the dummy motor ( thanks Chris ) and box are bolted together with spacers between to allow for the motor plate to be fitted later and the whole assembly craned over the beam

[brock]

   A series of simple screw jacks are made up to sit on the beam and allow the various bits to be aligned with each other and leveled . If we were going to use a solid drive shaft I would have used an index bar bolted into the motor's main bearing caps to align it all but with a prop and U/J's I am confident without it.

[brock]

   Having sorted the alignment, the whole lot is rechecked for level and centres

[brock]

   The front end is then mounted to the beam and the axle fitted and leveled to ensure that all is square and dimensions are equal side to side and diagonally

[brock]

   Then, just for fun, the first tubes were dropped into place. The seat area looks a bit tight so I will recheck that tomorrow before cutting anything. The nice Mr. Hall has left plenty of surplus on all the tubes so that I can still play with the final layout until I'm happy with it. The whole point of large scale drawings is to avoid this sort of thing and I am sure that after a couple of hours tinkering with it all I will end up with it as drawn, but still, a tinkering I will go. 

[brock]

   And tinkering I was. About an hours worth before I just dummied up what I had drawn and sat on the floor, yep, that'll work, just like the drawing. 

[brock]

Having rechecked everything a hundred times or so it was time to make some decisions. The length of the lower rear rails was set and the splice joint cut, holes bored to weld through and the tube set in the jig. The lower front rails were fitted and adjusted so as the bend was level with the front of the motor and the front scribed to fit the torsion bar

[brock]

deep breath and weld. Just glorified tacks at this time but heavy enough to allow a bit of brutal handling should that prove necessary

[brock]

   Now the more observant will have spotted that I had moved the position of the torsion beam cradle back along the beam, this was just to make it easier to walk around whilst the axle was mounted, not a critical thing really, but you might have mentioned that it leaves us short of beam at the other end.

[brock]

   This really is too early in the build to be finding problems so we will just continue like it was meant to be. I cut the rear braces to length off of the drawing and scribed them to both the lower and upper rail sizes , having checked the rule book ( again ) I cut and fitted the cross member and fully welded it whilst it was easy to get to it all.

[Manky Monkey]

Obviously I realised but thought you knew.  
The spliced joint's interesting as Loony & I were chatting to his mate, who builds super tough off-roading buggies this evening. We chatted about cutting & sleeving steering columns & he recommending cutting them on an angle just like yours, to give a greater weld area than a straight cut.

[brock]

   Then, as if by design, they will act as the jig to hold the top rails in place. Tomorrow, probably.

[Manky Monkey]

How do you plan to skin this beast Steve? In ally? Or is there another fibreglass mould taking shape that we haven't yet seen?

[brock]

   I'm not sure at the moment, I would love to do it all in ally and polish it but I may not have the time (or talent) and would soon get fed up with the upkeep. I suspect that the side panels and floor will be aluminium and I may try a fibreglass body, and if that is the case I may try for something quite flowing and pretty.