Austin Seven
Dad gets stuck in with some Cardboard Aided Design
At long last, as restrictions eased, my dad was able to come along and lend a hand with the Austin Seven Special project in person. He’d designed the body in two dimensions, taking inspiration from a number of period specials, but now was the time to add that all important third dimension.
A family affair
Arriving with a boot full of foam-core cardboard, dad quickly set to work. This sort of thing is his bread and butter, given his role as an Art Director in the film industry, and the process of creating a cardboard facsimile of the finished product is one he’s very familiar with. Along with my brother, Luke, who took several of the photographs featured in this report, we set to work, first establishing the position of the shortened radiator cowl before using the 1:1 scale drawing on the shed wall to measure from and create a rough bonnet side panel, through which the exhaust will eventually exit. We taped this in place, incorporating a ½in rise along the bonnet’s length to the bulkhead to give the perception of flatness (a tip I’ve been given by several respected sources while discussing the build).
This established a line for the front bulkhead, which we’ll revisit once I’ve collected a set of LWB Ulster-spec flitch plates from master Seven fettler Ian Tillman at Oxfordshire Sevens. Next it was on to the side panel, and the question of ingress and egress. Again working from the 1:1 drawing, dad marked and cut the curved ‘door’ before scoring the cardboard enough to allow it to belly out, much the way a ‘Nippy’ body does.
At the back, we set a point to aim for in the form of an ellipse on which the spare wheel will mount, bracketed from a crosspiece temporarily fitted between the Ruby chassis’ extensions where the fuel tank used to fit, and then set about adding a bulkhead behind the seats.
The finished body will need access through this bulkhead to the battery, fuel tank and space for a packet of crisps but that’s something to figure out another day. With forming trusses taped in position, some
more card could be
scored and an elegant compound curve formed between the seats and the spare wheel.
Standing back, the lines just weren’t quite right. The benefit of a card model is the speed and ease with which that changes can be made.
The low-cut ‘door’ line meant a sharp change in direction at the rear bulkhead, so with the scrap which had been cut out taped back in place, a second line was drawn and cut. Immediately, the lines flowed better. Several other small tweaks to the original drawing were made and soon we were happy with the overall ‘look’ of the thing.
We need to revisit a few areas, and sort the front end before I start cutting the shiny stuff, but we’re certainly getting there. It definitely pays to play with cardboard before expensive metal.
Powertrain progress
It’s not all been cardboard and gaffa tape this month. Following the return of the cylinder block from being machined, I placed an order with the Seven Workshop, then spent a happy couple of hours lapping in valves before fitting the shortened tappet block guides, reprofiled tappet blocks and re-faced adjusters then finally the valves with double springs, using the engine rebuild series in the Practical Classics Guide to the Austin Seven as my guide. It’s a good special edition, that!
Feeling cranky
I also unwrapped my precious Phoenix crankshaft and carefully secured it between blocks of wood in the vice before gently lapping the flywheel onto its taper. Once happy that there was sufficient ‘spare’ taper to pull the flywheel tight to, I removed all traces of grinding paste and set to work replacing the worn-out and oil-soaked clutch plates with new items.
The last job on the engine this month was to modify the cam bush to prevent sloppiness on it’s locating peg. Once aligned in the crankcase, I ran a 5/16in BSF tap from the crankcase into the bush for continuity of thread, ready for a short bolt to replace the original locating dowel.
Next month, I’ll be taking a trip to see ‘wobbly’ Steve Smith at Vibration Free, to tackle the next crucial stage in the engine building process.
‘The lines weren’t quite right, so we revised them with card and gaffa tape’