A rolling blog of everyday life on and around the workbench

12/03/2020: So there I was, standing in the pub around Christmas last year having a jolly good time quaffing ales and scoffing mince pies, when I found myself embroiled in a conversation with an equally festive lady who happened to be a violinist. The topic turned, naturally, to music - and at some point or other (possibly after the third pint) the prospect of getting together to start an informal folk ensemble was raised. I'd mentioned that I played the flute - but when she asked me if I also played the penny whistle, I'm afraid I did a terrible thing...and lied. "Penny whistle? Pffftt...sure, no problem!"
OK, technically it was a bit of a white lie because I do play the whistle - just not to a standard that I'd be happy to display in public. It was pretty clear, however, that she took my statement to mean I could stand up with the best of 'em, and I regret to say I did nothing to dissuade her of that notion.
Or do I? Because once the alcohol-induced bravado had evaporated I began to think that stepping up to the plate wouldn't be such a bad idea. I'd had a lot of amazingly good things fall into place in the last few months or so and it struck me that here was yet another opportunity waiting to be taken advantage of. I have a modest collection of whistles (including a very nice Howard low D), I have the time and the space to practice - all I needed was an excuse. And now I had one.

So I dusted off my whistles, pulled out some jigs and reels and set about bringing my playing up to a 'session' standard. And then I ran into a rather painful problem.
I suffer from a touch of arthritis in the base of my thumbs. It's not at the stage where it's debilitating (and I hope it remains that way) but it gives me a twinge on odd days, and it can sometimes make certain tasks around the workshop more challenging (key swedging and dentwork in particular) - and the way around it is to adapt the techniques and the tooling to ease the load on the affected joints.
What I found with the smaller whistles was that the distance between my right thumb and forefinger when playing seemed to hit the 'sweet spot' for the joint pain and made things all rather unpleasant. As I have no such problems when playing the sax, clarinet and flute I figured that there had to be a minimum distance beyond which my thumb was fine.
It was pretty easy to test this theory with the aid of an old wine cork and a lump of adhesive tack - from which I determined that 20mm was about right. This gave me no pain at all and had no discernible effect on my fingering technique - but it looked a bit unsightly, and I figured that someone out there must surely make a gizmo that does the same job and looks nice into the bargain.

Apparently not. The best that I could find was a blog post on the McGee flutes website (fantastic site, incidentally - heaps of in-depth info on all things flutey) which detailed the construction of what he called 'tin whistle buttons' to cope with the exact same problem I was facing - and rather helpfully he'd come up with a few measurements that would save me a fair bit of R&D time. Rather interestingly I noted that he too had found 20mm to be the ideal length for the button in terms of pain relief and playability.
I knocked up a few prototypes using his dimensions (suitably adjusted for the diameter of my whistles) and they seemed to work very well indeed. However, the more I looked at them the more I wondered whether the design could be tweaked still further. And they can - but not by much...so I thought I'd at least document my findings here in case anyone else has the same problem.

Delrin seems like the best material for making buttons. It's cheap, strong and has some flexibility...which is going to be an important factor in the way in which they work.
I began by drilling a cross hole through a length of 25mm Delrin rod. I could have used 20mm and saved myself a few pennies by not having to turn the rod down to size later on, but 25mm was all I had to hand.
The hole was drilled undersized then bored out to the required diameter. The body tube dimensions of a whistle aren't usually all that precise, which means having to work to a nominal measurement (effectively a 'ballpark' figure - take the highest and lowest readings then pick something inbetween) that turned out to be 12.76mm. The meant the hole needed to be 12.66mm. This dimension is important. The button needs to be able to grip the whistle securely and it does so by being a touch undersized and relying on the flexibility of the material to accommodate the difference - but you don't want it be too tight a fit or it'll be difficult to put on...and nor do you want it too loose or it'll just move about. Terry McGee's buttons were 0.3mm undersized - and while that works I found it to make the buttons quite hard to fit...and not necessarily as effective as you might think. We'll come back to that point later.

However, because the tube dimensions aren't all that accurate it means that the size of the button's bore hole needn't be that precise either. I found the easiest way to gauge it was to bore the hole out by eye and test it against a piece of rod of the required diameter (12.66mm) - in this case the shank of a drill. When the drill was just starting to fit in the hole, I'd hit my mark.

I've turned the rod down to the required diameter (20mm) and now I'm slicing off the waste. Those of you who know their way around a lathe might be wondering why I'm attacking the job with a hacksaw and not using the lathe to part it off. It's because parting through a hole in soft material sometimes causes the material to catch on the tool...which then digs in. At best this'll chew up the job - at worst it'll tear it right out of the chuck. I find it's safer and a lot less buttock-clenching to saw the end off and face it square afterwards. I know...I'm a big chicken.

Where this cut is made is reasonably critical because it needs to be some way past the centre line of the hole - and here's why.
The diagram shows the tube of the whistle end on, with the button fitted to it. The red line denotes the centre line of the tube's diameter. If you were to cut the button below the centre line if would fit around the tube well enough but wouldn't have any means of holding on to it. The moment you took your thumb off the button it'd fall off...unless you glued it in place.
With the cut made above the centre line the effective bore of the button begins to narrow - you can see that the inside edges of the top of the button aren't as far apart as the points which lie adjacent to the centre line. It's this portion of the button that grips the tube. The more material you have above the centre line (the overhang) , the more grip the button will have (up to a point) - but it will also make the button harder to fit. So there's a balance that needs to be struck.
In my experiments I found that Terry's 0.3mm undersized button certainly gripped very well indeed but was a right old job to fit. Granted, you can tweak it somewhat by reducing the overhang but I also noticed that it tended to wobble slightly because of the resultant distortion of the button's bore. This is why I went for just 0.1mm undersized - it's the closest fit to the diameter of the tube that still gives a workable grip.
That said, it's all a bit 'six of one, half a dozen of the other' - so as long as you're in the 0.1 to 0.3mm range, you're going to be fine (at least for a body tube of around this sort of size). I daresay there's an optimum height above the centreline too...

With the end of the button squared up and chamfered (to reduce the chance of contact with the fingers, and to look nice) it's time to clean up all the edges. I found that a sharp knife was the best way of doing this, but you could just as easily use a file or some sandpaper. And now is a good time to test the fit of the whistle in the button and make any adjustments as necessary. If you find it's hard work to slide the whistle in, try cutting a wider chamfer on the leading edges of the hole. It helps if you present the whistle at an angle then then carefully lever it into the button.
With the hole being only 0.1 smaller than the diameter of the whistle tube it becomes much easier to push the tube in from the top (as per a pipe clip), and you may find that some chamfers on the top edge will help. You have to be careful not to overdo it though, because that top edge is where all the grip is.
Once that's done all that remains is to part the button off to length and then finish it up as desired. I simply rounded the bottom over slightly and cut a couple of grooves in the face to give the thumb a bit of grip - but you could just as easily stick a piece of cork or leather on the face.

Here's a better look at the overhang.
The centre line of the whistle tube is marked by the blue line. In terms of grip on the tube both buttons stay nicely in place - but can be slid up and down the tube with reasonable ease as and when you wish to reposition them.
The shorter button has an overhang of 1.5mm (distance from top edge to bottom of hole minus half the hole diameter) and will clip onto the tube with ease - but if you tap it smartly with your finger you can knock it off the tube. I doubt the overhang could go any smaller and still hold the button on reliably. The longer button has an overhang of 3.5mm and takes some real effort to fit it. It will just about clip on, but not before it makes you wonder whether you're about to crush the tube. Sliding it on is less stressful, but still takes a bit of effort - and if you try to knock it off the tube with your finger you'll end up hurting yourself. I think a longer overhang would prove to be very difficult to handle, and would probably begin to foul the fingers as you played.
The takeaway from all that is that a shorter overhang is handy when you want to be able to clip buttons on just before you play (makes it easier to carry the whistles around) and a longer overhang means the button is less likely to fly off when you drop the whistle on the pub table. Anywhere inbetween is likely to be a very good compromise - and from looking at my figures it would appear that we have a sort of formula for the ideal button:

Hole size: 0.1 to 0.3mm smaller than tube diameter
Overhang: 12% to 28% of hole size

And that pretty much wraps it up for the whistles and buttons.
The biggest drawback, of course, is that you'll need a lathe if you want to make your own - though I suppose you could do a pretty reasonable job if you were handy with a power drill and a couple of files...and had quite a lot of patience.
I've also no doubt that this very basic design could be considerably improved upon; for example, some thinning out of the button around the overhang will make a big difference to the flexibility - as will using a different material (such as nylon). It might be advantageous to taper the bottom of the button into more of an oval shape, or round the top edges over rather than leaving them flat.
And, of course, there's no end to the amount of decoration you can turn into such buttons if you so desire...and they don't even have to be black. Or even made entirely out of one material.
In terms of feel I found they made little or no difference at all - but that's from the perspective of someone who hasn't played a great deal of whistle and is more used to very much larger instruments. If you're a dedicated whistler facing the onset of arthritis in your thumbs, you're probably going to find it all a bit strange for a while.

So I can now sit back and enjoy playing my whistles with comfort - while I wait for someone to email me to ask if making the buttons out of different materials will have an effect on the tone...