Saturday, 4 December 2010

Templates, temper, tempus fugit.

Last week I mentioned that there was something odd about about what I mistakenly called the "headstock/top tube gussets", when in fact I meant there was something odd about the top tube/down tube gussets. I blame the fallibility of the human condition, and the better part of a bottle of wine for the error in nomenclature.

Which brings me to the question, had you noticed the odd thing about the case in point? Admittedly it's not glaringly obvious, but the keen student will have noticed that the lovingly crafted and shaped gussets are going to be concealed by the petrol tank once it's fitted to the motorcycle. The immediate reaction is that must have been a mistake, or that at best, it's a bit pointless adding the decorative speed holes, only to conceal them under the tank.

In fact, it's neither an error, or pointless. To digress a little, back when I was making some effort to produce bespoke frames on a commercial basis, I used to cut out a cap for the open end of the centre post where it protruded through the cross brace, and sand and shape the weld to give a smooth appearance. Anonymous Don once asked me why I went to this trouble, and I told him that it was because the better a motorcycle looked, the closer people would look at it, and that in the fullness of time, someone was going to get on their hands and knees and look at the bottom of the cross brace. This statement, was met with scorn and disbelief.

A week or so later, Anonymous Don and I were attending a custom motorcycle bash, when Don was smitten with a revelation-ette on seeing a supplicant get on their hands and knees to inspect the underside of a motorcycle which was in the car park. Quod erat demonstrandum baby....

Carrying that idea further, in the BMW I'm trying to build a motorcycle that does nothing for the instant gratification seeking, Discovery channel watching, custom motorcycle enthusiast of recent vintage, while at the same time attempting to build one that rewards the patient observer. The more you look, the more there is to see.

Whether I have the ability to bring that off with any aplomb remains to be seen. Although, one would suppose that the advantage of being what is quite arguably insufferably pretentious in a subtle way, is that if you fail to bring it off, no one is necessarily going to notice. Unless you post that intent on the Internet of course...

So, while the speed holes in the top tube/down tube gussets will be obscured from casual view, I want the determined inspector of nooks and crannies to be able to spot them.  With this in mind, I've decided that I'll have the tunnel of the fuel tank satin black, allowing the silver painted (or powder coated in all probablity) gussets to contrast with their back ground, and that the gusseting on the headstock gussets needs to be, to paraphrase somebody famous on the subject of aircraft, a collection of holes held togehter by small pieces of metal.

As you can see, the steel gusset I made from the card template, had a fairly high ratio of hole to metal. sadly it didn't actually fit that well. More accurately, it didn't fit. at all. For some unaccountable reason, possibly not entirely unrelated to a somewhat unmerited glib attitude as a result of having done this several thousand times before, I neglected to offer the steel blank up to the frame to check that it was the required shape.

This was a bit of a shame, as it emerged that after I'd spent most of a day working out the hole spacing, checking that I had the requisite drill bits to drill the sequence of holes I'd arrived at, marking the hole centres, pilot drilling them, and then drilling them to their final sizes, the gusset, didn't fit. I suspect that what happened was that in the process of manipulating the card I used to make the template into position, I managed to pull the lower edge of it off of the line that ran between the edges of the factory fitted gussets I was planning ion boxing in.  The second picture, fuzzy as it is, shows me holding the second template I made for the gusset in situ. Despite the fuzziness of the illustration, it ought to be clear that the template isn't made of card, it's made of steel.

While it's only made of 18 gauge steel, this newer template has sufficient stiffness that it is reluctant to bend in one direction under hand pressure, let alone two directions. A closer look at the third picture should give you an idea of how much wider the gusset was that the space it had to occupy. Normally that wouldn't cause a huge problem, but as I'd already drilled the speed holes in the gusset, trimming it's edges down would have destroyed all my careful worked out hole spacing. The moral of that could be assumed to be that occasionally, the harder way, is easier, but I feel that the truth of it is that the ability to spot when you should be making a little more effort sooner rather than later, is an ability worth cultivating.

Christmas is approaching, and aside from all the usual seasonal mayhem, that also means that magazines want their stuff somewhat earlier in the month than is usual, so the next few weeks don't bode well for progress on the BMW...

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