I have made a new frame for a set of 1″ chimes, so it made sense to extend the playing range up to the top G at this juncture. The frame has already been delivered, so now I have the time to make the bells.
The first thing I need is an example bell, in this case I asked for the F. Not only does this enable me to take all the measurements that I need in order to make any parts, but it also helps during the tuning process so that the new bells fit within the existing set.
It is now virtually impossible to get brass tube in the size that I want, let alone the correct material. Brass is an alloy, so there are lots recipes to get the required properties for the desired application. Over time, brass is being replaced (presumably by plastic) so the commercial requirement for these mixes has largely disappeared. Combined with the mills being bought out during global monopolization, this has resulted in higher prices and less choice. Of course, if I buy sufficient quantity (a metric tonne) I can get whatever I want, but I am instrument maker – I make musical instruments for a living therefore I am poor; spending thousands of pounds sterling on lengths of brass tube is just not going to happen. Additionally I would need four external diameters, and three wall thicknesses, that is twelve tons of brass tube! If I had that kind of money, I would retire to the Caribbean.
Fortunately I do have some stock, which still equates to well over a thousand pounds just sitting on a shelf! In amongst those tubes I did indeed have a length of the correct material, which is the major hurdle negotiated. So the first job is to chop it into lengths longer than the bells I need to make. There is nothing worse than making a bell only to find that it is too sharp right at the end of the process when the tuning happens. With the two new tubes cut, I drill the holes for the string to match the existing bell and stamp the tubes.
Using the existing bell as a reference, I measure the cap dimensions so that I can form the inside of the cap from solid bar. This form is then cut off the bar giving me two crude caps. I use a donor bit of tube offcut as a temporary bell and spot solder the caps in place. This enables me to hold the offcut tube in the lathe to form the external shape. My lathe doesn’t have a large enough bore to pass the tube through its headstock.
With the caps now made, it is just a matter of removing them from the donor tubes and soldering them in place on the actual tubes. After they have cooled, I hand polish the whole bell, then tune it and send it off to be chrome plated if required.
It is a long time since I wrote part 1. This is what happens when I don’t get paid; all incentive to do the subsequent jobs fade away. Then of course when I do finally get paid, the work has to be rescheduled. In the mean time I have a hundred and one other jobs to do and the weeks roll by. The other side of not getting paid of course is that I can’t buy food, or pay my bills, but that whole concept fails to register with many of my customers!
Anyway, I digress (as usual). So in part one I got to the point where the bases could be welded. As you can see below, I have totally reformed and trnasformed the under side of the casting.
Another classic bodge job is just bolting a caster on when the big tilt stem has been lost. The caster was held on with a 10mm bolt, the hole in the casting for the tilt stem is 19mm. I find it staggering that anyone would think that that was going to work.
There is little that I can do with the resulting damage. Fortunately, the casting is thick and the thread is coarse, so after re-tapping the holes, replacement tilt stems works well. Easy job really if you have the equipment and the parts. If you don’t have either, they shouldn’t be doing the job!
When I overhaul a set of timps, there is a lot of work involved over a period of days or even weeks. My approach is to fix everything properly; I am after all a professional and that is what I am being paid to do. However not everyone is as conscientious, and in the end, you get what you pay for. So when I work on timpani, I am fixing problems associated with wear and tear, and the dogs dinner that the previous person made of the job. The posts on timpani pick out examples of problems I encounter, rather than me writing, and you reading the same thing every time I do a set of timpani (which is why I have coloured this bit blue).
Very frequently I get jobs in to do that have obviously been repaired by someone else in the past. We all have different standards, budget constraints, levels of knowledge, skill and methods. All that I accept, and it is useful for me in order to evaluate what I do. However sometimes I almost laugh in disbelief at what I am seeing.
I can see why they have done this – the base casting has practically worn away, but ignoring the facts that it won’t work, and it has been done really badly, it looks bloody awful.
Removing all of that mess in itself is a job. What it reveals is the state of the castings prior to the last repair. To me it looks like no preparation was done at all.
So all the sharp edges need to be filed smooth, and some of the bits that look solid, are in fact like tin foil. What I need to do the job properly is solid metal.
Now at least when the repair is done there will be clean lines and it will look good as well as actually doing the job. All it takes is a little bit more effort and time, and respect for other peoples property.
These will now go out to be aluminium welded, so the post will continue.