I’ve managed to spend a bit of time on the car this weekend. First of all, I wanted to be really sure that the diff was going to fit properly. So, I cut out some supports for it, following the CAD model that I showed you a short while ago. However, in an advance on the normal materials technology I used hardboard rather than aluminium for the diff support plates. It’s much easier to cut out, so it’s bound to be a better choice.
Category: suspension
Two car Tim
There’s quite a lot of good photos around of the race at Snetterton. The one shown here was taken by Derek Jones’ Dad at Russell chicane. That’s Tony just behind me, thankfully.
Creeping forwards
There’s another race meeting coming up so I needed to sort the Fury again. After Silverstone I was concerned that I might have deranged the suspension after narrowly missing a spinning Duncan by escaping over the huge kerb at Becketts. I noticed at the weekend that the F1 people were whinging about Monza having put some huge kerbs in. Serves them right, I reckon.
So, I tipped the Spectre chassis on its side-it’s still light enough to do that-and put the Fury in an accessible position and spent a merry 5 hours checking the suspension alignment, which all seemed to be fine. Hmm, that was a waste of time then.
De-fumigated
After getting grey gunge all over my arms, I seem to have decided that I’m not happy with the POR-15 as a chassis treatment. It didn’t seem to be working as well as when I did the same thing to the Fury after setting that on fire. The difference is that back then I’d just had the chassis shot-blasted and that provides a pretty good key for paint-like stuff. So, I think I’m going to get the chassis powder coated and I phoned a local company, GKL Coatings, that Dan has used for powder coating and they sounded pretty competent so I’ll take the chassis there in a while. However, that means I really need to get everything that I want to do to the chassis done as soon as possible.
Fumigated…
Having now got the front uprights from Jeremy the first job was to take them to bits! So, I took the bearing caps off and hence the hubs and exposed this rather nice looking spidery thing. These uprights are interesting in that they’re essentially a set of parts. The bearing support shaft here is just held at the back of the upright by a big nut. The steering arm, as you can probably see, is also a separate part.
Stand upright at the front!
I’ve finally got the front uprights through from Jeremy, who hadn’t received them from his suppliers for ages. Here’s a photo of one of them, as you can see it’s jolly shiny!
Oddly, I seem to have two discs too, which I didn’t realise that Jeremy was going to supply. They’re not the size that I’m going to use, and have already bought, but I might be able to press them into use as spares, I suppose.
Swarf
Lots of it, in fact. I’ve been lathing away following Dan‘s suggestion on my post yesterday about how to resolve the issue about welding the super-thin sleeve into the bearing housing on the wishbone. His suggestion, which is pretty obvious in retrospect, like all the best ideas, is to leave a flange on the end of the sleeve that’s sturdy enough to be able to weld it to the housing. The only issue with this that I can think of is that machining the sleeve to exactly the right length is going to need lots of assembling and disassembling, but that’s no great deal really.
Balls, sphericals in fact…
I’ve finally managed to finish all the Delrin bearings which is a great relief. Mind you, as I went around the car I rather refined the process. So much so that the last few were much better than the earlier.
“Like pancakes”, Anthea said. Indeed, something to do with the frying pan, methinks.
Acetal swarf…
…I seem to have been filling the garage with it as I’ve been making the suspension bushes that I talked about. It took me a while to work out the best way of making them but I’ve mostly done it now although it’s taken an alarming amount of time for a few grams of car. Along the way I’ve reduced about 1500mm of 28mm diameter Delrin rod to, largely, swarf that’s in the bin. The big issue, actually, has been getting the tolerances right so that the bush grips properly in the wishbone but rotates around the bearing shaft properly.
Suspending a spectre
I’ve still been thinking about suspension bearings. At one point I’d convinced myself that the thing to do was just to cut up the existing wishbones and weld some bushes in into which I could put some rod-ends. I still might do that, to be honest. In fact, I suspect Jeremy would be happy to provide a complete set of new ones.
However, in the meantime I was talking to one of the Baldwin chaps at Silverstone. Ian is one of the main designers of the BDN car that won the championship last year. What’s more, his new car is running well this year although hampered by a late start. I was talking to him about bushes and he said that the new car, as a bit of an experiment really, was using bushes made with Acetal. This is an engineering polymer that is commonly used for similar things. I did some calculations and it does look as though it’s up to the job. (And, to be honest, it’s clearly tougher than bungy rubber or nasty polyurethane anyway.)
So, I bought a stick of it to see how it goes.