A rolling blog of everyday life on and around the workbench (Archived - July 2017)

18/07/2017: It's toolmaking time - which takes me back to my early days at Merton Technical College, where the first few weeks of the Musical Instrument Technology course (aka how to be a repairer) were spent making tools. At the time I couldn't quite understand why such a thing was necessary - surely you could just buy any tools you needed?
Well, yes, you can...most of the time - but specialist tools aren't cheap, they're not always quite what you want, they're seldom available in a hurry...and did I mention that they're not cheap? So having the ability to make your own tools is very much an advantage.
For the most part I find myself making tools that I need for a particular job - but from time-to-time it's necessary to re-make tools, such as when the old ones wear out. And what tends to wear out first are the reamers. These are typically used during the key fitting process to shorten and square up key barrels and to dress pillar faces, as well as to bore out point screw pillars to allow the screws to sit deeper within the pillar.

It's not so much the use that wears these tools out, rather it's the act of sharpening them. Over a period of time the cutting faces recede further down the tool, and it gets harder to maintain any kind of precision at the cutting face - and, quite frankly, it's quicker to make a new tool than it is to faff around trying to bring a tired one back up to spec.
It also provides an opportunity to have a think about how the tools work, and to try new ideas out. For example, on the left you can see a pair of flat reamers. These are very simple but effective tools. Used properly they're very accurate as well as being easy to make and maintain. The biggest drawback is that the standard design (my old one is on the left of the pair) doesn't have a wide range of usability. It has set dimensions - which means you have to make a whole bunch of them in various sizes. The new one on the right is more 'modular' in that the central pilot is removable. Being able to swap the pilot out for one of a different diameter and/or length makes the tool far more versatile...and it takes a lot less time to knock up a new pilot than it does to make a new reamer.

So there I was, churning out a few new reamers, when I thought I'd have a go at making a tubular reamer.
This type of reamer has a distinct advantage over the flat reamers in that there are more than two cutting faces. This makes it easier to ensure the cut is perpendicular to the job.
However, having multiple cutting faces means it's more of a pain to sharpen - though it shouldn't be too hard to make up a sharpening jig.
You can, of course, buy these things ready-made - but if you think about what's required from such a tool it soon becomes clear that they're not really that hard to build.
There are really only three critical points; the first of which is that the cutting face must be perfectly square to the body of the tool, and perfectly flat. The second is that the inner diameter of the tube must be smaller than that of the item you're cutting - and the third is that the outer diameter must likewise be greater than the outer diameter of the item. And that's about it.

But what about the 'teeth' - the actual 'business end' of the tool? There's a lot of science that goes into designing cutting tool faces, and in many cases having the right or wrong angles on the tool can make or break the job - but when you're cutting materials as soft as brass and nickel silver, you really don't have to be quite so precise. Indeed, you'd actually be hard put to make a tool that won't cut brass - but life becomes a great deal easier if you can make a tool that does so efficiently.

The starting point is to make the tool out of the right material - and in most cases this means silver steel. The beauty of this material is that it's easy to turn and shape - and when you've got it to where you want it, it can be hardened by heating it up to red hot, holding it there for a minute or so and then dunking it into water or oil (depending on which type of silver steel you've chosen to work with). This makes the metal incredibly hard...but also leaves it quite brittle, and so it's common practice to re-heat the tool somewhat to put it through a process known as tempering. This retains most of the hardness, but relaxes the metal and makes it less brittle. Personally I seldom bother with tempering such tools, as they're unlikely to be used on anything that could break them (and I've never broken one yet).
So you grab a piece of silver steel rod, chuck it up and centre it in the lathe, face the end square, drill out the central bore and tap it with your chosen thread. I'm old school, so on this one I went for 7BA.
Then you have to cut the teeth.
You could set up a dovetail milling cutter and a rotary table and cut the teeth to mathematically perfect dimensions and spacing...but it takes bloody ages to set it all up - so I simply sat down at the workbench and had at the thing with a square needle file. Ten minutes later I'd cut five teeth...while the other me was still poking around in the tool cabinet looking for the dovetail cutter (he won't find it...I broke it a couple of months back).
It really doesn't matter if the teeth aren't perfectly spaced - as long as each tooth presents a flat face to the job followed by a relief angle, this'll give you your cutting edge. A quick touch-up with a sharpening stone after hardening the reamer will hone a nice sharp edge to the top of the teeth...and that's really all you need.

And here's the tool in action.
The removable pilot (which needs to be a snug fit in the key barrel) keeps the tool aligned in the correct plane, and thereafter a bit of gentle pressure and a few turns (by hand or with a slow drill) is all that's needed. As you can see from the swarf (or chips, as our friends across the pond like to call it), it cuts very well - and the extra teeth help prevent the tool from rocking and leave a good finish on the end of the barrel.

I dare say I could have bought a tool for the amount of time it took to make it, but there's a certain joy to be had from using a tool that you made yourself - and you can take the time to tailor it to your specific needs. It keeps your hand in, as they say in the trade - and I believe it provides a better understanding of how and why such tools work. And that can only be a good thing.

03/07/2017: I've had one of those "Well, duh!" moments.
Some time ago I swapped out my faithful old K&M tenor stand for a shiny new Hercules - you know, the foldy-up yellow and black thing with the nifty-tifty self-clamping bell clamp. And very nice it is too.
However, there have been a number of occasions where the sax has slipped sideways of its own accord. It hasn't fallen off - but it looks like someone's walked past the horn and given it a bit of a nudge in passing.
This wouldn't be much of an issue if there was a 'nudgist' - but there isn't...the horn is slipping without any external influence.
Actually, that might not be completely true. It only seems to happen when I'm on stage, so I reckon a combination of movement of the stage floor and/or the vibrations from the drummer/PA are the culprit. Either way, it's never been an issue with any of the other stands I've used.

Normally I'd simply write the thing off and get something else, because you have to wonder just how far the horn might eventually slip - and a stand that doesn't keep your horn standing isn't a stand at all.
I wondered whether the angle at which the horn is held might be the problem - it seems rather upright - and I'd tried to address this issue by drilling another detent hole for the riser lock. Unfortunately it didn't work out very well - the nearest spot at which I could drill a hole left it at too shallow an angle.
I probably could have drilled the hole a little closer to the original one (on the right) - but it really needs to go right between the two holes. There's no practical way of doing this other than welding up the holes and drilling a new one (I don't have a welding kit) or combining the two holes and making up some sort of adjustable detent (a complete faff).

But a recent thread about sax stands on Cafesaxophone prompted me to think about the matter in a little more detail.
The whole idea was to tilt the angle of the stand back, and a new detent for the lock wasn't going to work. You could, in theory, simply bend the riser back - but this would likely have a dramatic impact on the strength of the box section...and it would take a fair bit of grunt to bend it.
You could raise the height of the front feet, but this would almost certainly affect the stability of the stand - and, again, it wouldn't be easy.
And then it came to me.

The whole thing is held together with bolts. With the aid of a couple of 10mm spanners you can strip the stand down into its components parts in less than a minute - but most importantly, the pivot block for the riser is secured to the base with two bolts. And where there are bolts...there can be washers.
And that's it. That's simply it. To alter the angle of the riser you just need to shove a washer or two between the base and the pivot block at the bolt nearest the riser's pivot point.
Well, duh indeed.

It was clear to me I needed to save some face after the new hole debacle, and I didn't much like the way the stand looked with a couple of washers stuffed in the base - so I knocked up a nice neat wedge instead.
Yes folks, I'm giving Hercules a wedgie.
I also noted that a few other players have mentioned that the stand seems a little too upright, so I thought it might be handy to share the dimensions of the 'Hercules Tonewedge'™ in case anyone else out there fancied a go at modding their stand.
The basic requirements are simple enough - you need a piece of metal (mine is steel, but aluminium will do just as well) 20mm wide by 32mm (approx) long. I went for a piece 4mm thick. You could go thicker, and this would give you a shallower angle on the riser.
You'll also need a new bolt. The existing one measures 30mm on its shaft - and with the additional thickness of the wedge it'll no longer protrude through the bottom of the base. And it needs to be a coach bolt - which has a square section under the head. You'll need this to locate in the pivot block, which has two square holes for the bolts.
You'll need to modify the bolt. You'll probably find the nearest size you can get is a 50mm (2 inch) bolt - and this will give you plenty of leeway for cutting it to the right length depending on the thickness of the wedge. For a 4mm wedge a 32mm shaft is ideal.

You'll also need to slightly flatten off the top of the bolt. The original ones are flat headed - but most coach bolts will have a larger, rounded head on them. The diameter of the head isn't a problem, but it's just a tad too thick. A few passes with a file are all you'll need so that the bottom of the riser can pass freely over the head of the bolt.

It's up to you how you make the wedge, but I marked off a 32mm section in a longer piece (makes for easier handling) then ground the wedge from the tip back up to the marker. You don't need to taper it to a fine point - there's going to be a small gap between the tip of the wedge and the rear bolt anyway. I also drilled the hole out first so that the wedge could be fitted to the stand from time-to-time to check the fit and alignment.

Here's the wedge in position - and it works a treat. The larger head on the bolt doesn't interfere with the operation of the riser...but if it does, just file a bit off it where appropriate. It's a much neater solution than a couple of washers and it maintains the rigidity of the base.

And here's how the stand looks now when compared to the original setup (in shadow).
It's only a slight tilt backwards - the original setup was around 60 degrees, the wedged setup is 50 - but the horn seems to sit more solidly on the stand. Whether this will stop it shifting sideways remains to be seen, but the balance of the stand certainly feels better.
I may try a slightly thicker wedge - maybe 5mm - but some thought has to be given to the horn's centre of gravity. Tilt it too far and the stand could go unstable.

All I have to do now is figure out what to do about the superfluous detent hole. I think I'm gonna leave it there - as a constant reminder of the truth in the old adage....measure twice, cut once.

*Postscript: Tried the modified stand out at a gig (with a wobbly stage) and am happy to report that it seems much more stable. I'll keep an eye on it though...just in case.

01/07/2017: I've been doing a bit of stripping (yeah, I know). I don't tend to do a great deal of this because I usually turn such work away - for a couple of reasons.
Firstly, it's nasty work. It's messy, the chemicals are nasty...and, frankly, it's just plain tedious. And secondly, it's often requested by players who feel it's going to make a change to the way their horn plays.
In fact it probably will, but it won't be down to having had the lacquer removed - it'll be down to the necessary setup work when the horn is reassembled. I don't feel at all comfortable selling what's essentially a fake service...so I don't do it.

However, there are times when it's a viable part of a repair - such as when the lacquer is so bad that the corrosion forming beneath it is starting to damage the brass. Or, as in this case, when it really shouldn't be there and it's been very badly applied.
This is the (very) old Couesnon soprano that recently got a mention in the Black Museum - and as part of the ongoing 'underhaul' it's now time to get rid of the appalling 'homebrew' lacquer job and restore the horn to its original silverplated finish. Easy-peasy - just slap a load of paint stripper on it, give it a good few minutes to brew and then wipe it all off. Or at least that's how it used to be.
Whenever I've done this sort of work in the past I've always reached for a tin of 'the old faithful', otherwise known as Nitromors. This stuff has been the industry-standard stripper for years. Or at least it used to be. Just like another old faithful - Evo-Stik - it's fallen prey to rules and regulations and is now but a mere shadow of its former self.
I had a tin of it lying around - most likely because I'd bought some to do some household paint stripping, found it hadn't worked and then bunged it on the shelf - so I thought I'd give it a go anyway.
I needn't have bothered.

So I did some digging around and found that you can still get 'proper' paint stripper...if you know where to look and what to look out for - and just for fun I thought I'd do a little head-to-head to see how each of these strippers fared.

Here's the setup - a section of lacquer on the Couesnon's bell, just below the low B (it only goes down that far).
The plan is to spread a dollop of each stripper on the lacquer, set the stopwatch going and see how they fare over the minimum reaction time as specified on each tin...which is 10-15 minutes. I've cleaned and degreased the lacquer to get rid of any dirt and oil that might skew the results.

The strippers are on and the clock's running. The Nitromors is on the left, the Power Strip is on the right.
Apparently the Nitromors is tinted green so that you can see where it's been applied. It's probably a neat idea if you're stripping a load of white paint, but on a horn it's a bit bloody useless. I should also point out that the Nitromors tin proclaims that it's the 'New double strength formula'. We shall see.

We're a minute in and there doesn't appear to be any change on the Nitromors side, but if you look closely at the Power Strip side you can just see some slight blistering on the lower edge.
That's very encouraging - and I have to say that it took some very considerable restraint on my part to resist the temptation to give those blisters a bit of a prod and a poke. I could hear them calling to me...."Go onnnnn...you know you want toooooooo".

Five minutes in now, and things are looking good on the Power Strip side. The blistering has spread and the lacquer at the lower end is starting to sag. I really, really want to pop those blisters...but I know I have to be strong.
The Nitromors doesn't seem to be doing a great deal. The surface has gone a bit puckered, and perhaps this crazing indicates that the stuff is beginning to work. It looked a bit dry though, so at this point I dropped another dollop of strippers on it - and just to be fair I also added some more to the Power Strip side, even though it didn't look as if it needed it.

The clock's been running for fifteen minutes and there still doesn't appear to be much happening with the Nitromors.
I took a shot at ten minutes, but it looked much the same as this one - which probably means both strippers have done all they're going to do and it's all over bar the shouting.
The extra dollop added after the five minute shot doesn't seem to have made any difference - the Nitromors still looks slightly crazed, the Power Strip now appears to be a single complete blister.

And at last I can satisfy my gnawing desire to poke those blisters, because the time's up and we need to see just what's underneath all that goo.
As you can see, the Power Strip has done very well indeed. Virtually the entire area that was treated has been stripped, with just a couple of spots hanging in there. It also stayed quite liquid and really didn't require that extra dollop at five minutes in - and had probably done its work after just ten minutes.

Things are not good at all on the Nitromors side. There's no sign of crazing, no blistering...not a mark. The slight crazing I thought I saw in the lacquer turned out to be nothing more than the paint stripper drying out. In fact there's so little effect you could probably use this stuff as lacquer polish, for all the good it will do.
I should point out that Nitromors make several different varieties of stripper - so it may well be the case that one or other of their products would have yielded better results. That may well be the case, but the standard 'green tin' stuff has always worked well in the past...and it says 'All Purpose' on the tin. Not so much Nitromors as Notromors.
Maybe it needed more time - but when it's up against a product that can do the job in ten minutes, I think it's reasonable to set the bar right there.

So there you have it. If you find yourself in the mood for a spot of lacquer stripping, I can certainly recommend the Power Strip. It's made by a company called Maxolen, and I picked this 1 litre tin up off ebay for just under a tenner delivered.

*Postscript: After I'd removed all the grotty lacquer it turns out the horn isn't silver plated after all - it's nickel plated...and almost all of it's intact.