Uprights...

I'm back... I did take the laptop away with me to a very nice part of Wales, but it was so nice, I didn't actually take it out of the bag at any point during the week. Anyway, as I've still got a week before I have to go back to work, I've got some time to crack on with the design.

For my other reader, the upright is the business end of each wheel station. It carries the hub that the wheel bolts onto; the outboard pickup points for the suspension; the joint for the steering arm; the brake calliper and the brake disc as well. In short it has to resist all the road loads into the chassis without deforming.

There are three ways of manufacturing an upright: casting, machining and fabrication. Now, while I do have a fully working forge, I'd wager that very few hobbyist builders out there do. Casting is wonderful for many reasons but for small runs it's extremely expensive and you tend to have to do a lot of machining on the finished casting anyway. So I can probably safely discount it.

Machining is what I'm best at, but the cost of a lump of billet might scare a few people - a 2" x 2" x 3000mm (don't you just love industries where Imperial and Metric dimensions get mixed about) billet costs around 150 GBP and with a decent design most of that billet will be converted into swarf. Most 'professional' race cars tend to use machined billet uprights (the McLaren F1 did as well) and as it's someone else's money when we're living in virtuality, I'm not necessarily worried about wastage.

Fabrication is a very efficient way of manufacture, but it requires real craftsmanship to get an accurate finished item with no structural weaknesses. A good quality fabricated upright probably isn't going to come out of an amateur's garage with the aid of a Machine Mart MIG welder. I don't think I'd be happy racing around with something I've welded together, and welding pretty much guarantees the use of steel and it's resultant weight penalty.

So, machining it is and the next job is to get a few parts modelled up for further use: the brake disc and the calliper space model (i.e. I only need the outside dimensions rather than an exact 3d model with all the fillets, chamfers and the like). I'll be back after I've got busy with Solidworks.