Tuesday, 28 December 2010

The Horse Latitudes

Between 30 and 35 degrees North of the the equator and between 30 and 35 degrees South of the equator, are what's known as "The Horse Latitudes". I was taught that they were called this because ships were often becalmed there, and any livestock on board would perish and be thrown overboard.

Apart from throwing dead horses around, this period between Christmas and the New Year always feels like that to me and I can seldom muster much enthusiasm for anything other than the traditional seasonal excesses. In the course of the week leading up to Christmas, I did manage to make a new r4ear brake actuating rob for the BMW, but that was the sum total of my productivity I'm afraid. Making a brake rod doesn't sound like much and in all honesty it isn't, but I did manage to make rather more of a meal of it than you might imagine to be the case. The initial intention was to re-use the original item once I'd managed to persuade it to detach itself from what used to be the brake pedal, but is now the idler for the rear sets. That didn't exactly go swimmingly well, and I ended up breaking the retaining clip on the clevis pin, though I did manage to free the stop screw and nut off with out any further displays of ham fistedness. 

A scout around the workshop produced a selection of left hand threaded Rose (or Heim if you prefer) joints with an M6 x 1.0 MM thread. I'm fairly sure that these were originally some thing to do with a gearchange linkage and came to be lurking around when two of the linkages were modified, using a new rod and the right hand threaded joints. As I bought a left hand thread M6 x 1.0MM die to make the linkages for the rear sets, threading the end of some 6MM bar to accept the joint and a lock nut  was simply a matter of remembering where I put the die. Once the new rod was fitted with a pivot and cut to length, I threaded the other end to accept a nut to act as a stop for the spring, and the original brass wing nut adjuster. It's fairly obvious that tapping that much thread along the rod was a fairly time consuming job. What's possibly less obvious is that the spring was quite a time consuming job as well, as I wound it myself. It's actually one of a batch of 10 or so that I made a while ago using the screw cutting facility on my lathe and a couple of simple tools. 

That, in all likelihood concludes the progress for this year, and frankly, I've forgotten what I was planning to do next, so that will have to come as a surprise to us all.

Monday, 20 December 2010

A Christmas get together.

Having had a bit of a rest, I got on and welded up the rest of the frame. I'm not wildly enthusiastic about the result, but it's not going to fall apart. Bits of it are definitely better looking than other bits, which is partly because I don't have the balance I used to, and partly because, I was rushing it and lacking in patience. Still, nothing that a grinder and a more measured approach wouldn't sort out, should I decide that it needs sorting out.

With the welding done, the next major task is going to be sorting the engine out, and with that in mind, I've started looking at the ignition. I'm flirting with the idea of crank fired ignition, simply because it means I can lose the bean can that houses the points. That's little more than a research project at this stage, and the immediate  concern is really an ignition coil mounting bracket, for which I need some idea of the coil I have to mount.

What the motorcycle needs at this point is a penultimate re-assembly to check that everything goes together and works as advertised to avoid unpleasant surprises once everything is painted, powder coated or plated. With that in mind, I drilled some more speed holes in the footrest hangers and cleaned up the last traces of any bracketry that I'd lopped off of the frame and sub-frame. Finding homes, or more accurately, making homes, for the ignition coil, regulator, rectifier, a horn, and the mythical fuse box, before the frame is powder coated or painted, makes a lot of sense to me.

Because of the episodic nature of my motorcycle building antics, combined with the unreliable nature of my memory, I have a tendency to leave minor things undone, and then forget about them. For instance the seat hump needs drilling for some screws to attach the rear light, a task which remains undone as I haven't determined whether too use small screws and nuts, of which I have none, or self tapping screws and speed clips, of which, I am equally devoid. Things like that tend to suffer from the need for them becoming apparent at 5:30PM on a Saturday evening, and my not resurfacing at the workshop until something after mid-day on Tuesday, which is plenty of time to forget what I need, for whatever it is I need it for.

Bad weather, Christmas, and the New Year mean that progress over the next fortnight or so is unlikely, but stranger things have happened.

Sunday, 12 December 2010

Raiders of the Lost Parts

Despite the auguries to the contrary, I did actually manage to make some tangible progress on the BMW this week. It started badly with my trying to get some one on the phone who knew about Acewell digital speedos, as I'm a bit unclear about which would best serve my needs, and failing miserably at that.

Havng arrived at Friday slightly tired, dazed, and not entirely sure why I was in the workshop, I turned around and got back in my car, and instead of doing the sensible thing and heading for home, I went to B&Q and bought a length of 12mm threaded bar, and some suitable nuts and washers.

 The reason for buying it was that I couldn't find the original fine thread nuts that went on the two original engine mounting studs, which meant that I couldn't tighten the engine mounts, which in turm meant that I couldn't make sure that the frame splices were correctly aligned. While threaded bar isn't suitable for use as an engine mount, it can certainly substitute for one right up to the point where the engine is fired up. Certainly in the past, I've noticed that people assume that because I've used it while constructing a frame, it's going to fine as an engine mount. The truth is that I use threaded bar for these applications because its' more convenient, the coarser thread saves time winding nuts on and off, and if I damage the thread then I haven't wrecked a stud which will have require more investment of time, energy, and often money to replace. Once I'd cut a couple of lengths of threaded bar, I cleaned up the cut ends of the frame rails and bevelled them and the splices ready for welding.

Aside from the nuts for the engine mounting studs, I'd also managed to lose the steel template I'd made for the gusset to go between the existng factory headstock bracing. At one point on Friday, there were three of us searching for it in what was in increasingly unlikely places. I eventually found the thing in plain view of everyone. I'd left it on the bench with the gussets that I'd already made, and some how it had got knocked off of the bench, whereupon the force of gravity had taken over. I'd suspected this as a possibility and had assidously searched the floor area around the bench in my quest to find the thing. What I should have remembered is that gravity is a very weak force, because on it's way from the bench top to the floor, the template had passed the magnet that lives on the side of that particular bench, and magnetism being a stronger force than gravity, it had snatched the template for its own. Which goes to show, even particle physics can come in handy from time to time.Having found the template, I went on to make version 2 of the gusset, and add it to the collection.

Saturday dawned a much warmer day than had been the case for most of the week. I know that because after I woke up in the middle of the morning, I was told so by Samm, who knew it because she'd looked it up on the Internet. Rolling into the workshop at around half past one, I started plodding my way through the welding, and sorted out the detachable frame rail.

With that done I double checked the headstock gusset gusset, which I suppose ought to be called a boxing plate. as that's more or less what it's doing. With that finessed and tacked in place, I tacked the rest of the reinforcements  in position, then preheated them with my propane torch and welded them.

I mentioned last time that the top tube to down tube gussets were going to hidden by the tank, but that the determined obeserver should be able to spot them, and as you can see in the last photograph, that is the case.

Because I was getting tired and my welding seems to suffer for it, I opted to wrap it up as soon as I started fumbling things rather than press on and do the few remaining bits of welding. I'm hoping I can get that done in the week and then start reassembling the motorcycle to make and finish off any odds and ends of fabrication, before I make a start on the engine as I'm hoping to get the paint and so on done while I'm overhaulng the drive train.

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...