Making a simple lyre

[Ian Lynagh]

Hi folks,

I'm planning to build a simple lyre, probably similar in design to the cheap ones that Amazon and the like are full of. i.e. roughly 40cm x 26cm x 3cm (15" x 10" x 1"), diatonic C scale with at least 16 strings G3-A5.

I've never done anything like this before, so I was wondering if anyone is able to help with any of the questions I've run into please?


The first thing I've been wondering about are the zither pins. I'm in the UK, and have found places selling Gewa, Viking and "C. B. Gitty Crafter Supply" branded pins. Does anyone know whether any of these brands are particularly good or bad quality, or should I just get whichever is most convenient?

The other thing is that I've seen a couple of kit building guides tell you to hammer the pins part of the way in. Is this really recommended? I would have thought that screwing them all the way would be better?


On strings, from what I can tell metal ball-end strings are what I want. Hopefully Galli is a decent brand, because that's the only one I've found

I'm quite confused by how to work out what diameters/lengths to use for the various notes, though. For example, https://www.harpkit.com/resources/steel-string-selector says that G3 on a reverie harp is 16" 0.042", but https://www.harpkit.com/reverie-harp-string-set has two G3 strings, a 16.75" 0.032" and a 16.875" 0.042". My understanding is that for a given tension and pitch, length multiplied by diameter ought to be constant, so I'm quite confused by this.

I've actually ordered an ultra-cheap kit to experiment with, so hopefully that'll give me a better feel for what string diameters make sense. I might also order a few sizes of decent string to play around with. If anyone has any tips on how to calculate sensible lengths/diameters, I'd love to hear them though!

I'm also wondering if there's any rules of thumb about minimum instrument sizes for different pitches. I have suitable wood to make the lyre taller, allowing for longer strings, but all things behing equal I would prefer a shorter, lighter instrument. If that's going to result in disappointing sound then I'd definitely prefer to go longer, though.


Finally, the overall construction. I have some mahogany/sapele that is sufficiently big, so I thought that I would try making it essentially as if it were from a solid block of wood. So my plan would be, as I've tried to illustrate in the image below:

• Drill a 5cm (2") hole half way through; this will become the sound hole
• Cut 3mm off of the back and front (I guess thinner is better, if I dare!)
• Cut out a section from the middle; this will becomes the soundbox
• Glue the front and back on again
• Cut out another section; this will allow access to the strings from the back

In reality it will be a little curvier than the image shows, have a bridge (and perhaps reinforce the inside of the soundbox under where the bridge will be), but that's the general idea.

One thing I'm not sure about is whether I need to worry about the grain direction where the strings will attach, at the top and bottom of the instrument. As far as I can tell, the cheap lyres don't worry about this, so I expect it will be fine, but perhaps they are designed to have strings with lower tension than is desirable? I can make these sections as thick as I like (I was thinking 3cm, so a bit over an inch), but the thicker I make them the further up the bridge needs to be (at least, I assume that it needs to be over the hollowed out wood), so the shorter the string vibrating length would be.

The other thing this approach does is to give me a mahogany/sapele sound board, rather than spruce/cedar. But I'm pretty sure that this is not that uncommon, so hopefully that won't be an issue.


Anyway, any advice gratefully received, and sorry for such a long message!


Thanks
Ian

[Ian Lynagh]

Well, the kit arrived, and I also got a Viking and Gewa zither pin, for science. Unfortunately, while the kit and Viking are 5mm RH thread, I could only get a Gewa 5.5mm LH thread at a sensible price.

From left to right in the first picture:

The kit came with 7 pins, and I was impressed that all of them weighed 5.72g according to my scales. I'm pretty sure that they are a 5mm body, but I measured the diameter including the (relatively) coarse threads as 5.3mm. I make it 26 threads in 17.5mm, so 1.49 threads per mm.

The Viking is the only one that is blued. 6.00g according to my scales, and I measured it at 4.9mm diameter. I make it 64 threads in 21.5mm, to 2.98 threads per mm.

The Gewa is the heaviest at 6.75g, but is also 5.5mm diameter (which my measurement agrees with). I make it 45 threads in 15.5mm, so 2.90 threads per mm. Not far off the Viking, and it may be that a 5mm Gewa would have denser threads.

I would imagine that the coarser threads of the kit pins will not hold as well, and they may also be less corrosion-resistant than the branded pins. The Viking and Gewa threads seems largely similar, so currently I'm inclined to go with whichever I can get 16+ of cheapest.

Next step will be to put the kit together, to get a better understanding of strings, I think!


Thanks
Ian

[Jim McConkey]

The coarse threads should hold just fine, but the finer threads will make the instrument a lot easier to tune.

[Ian Lynagh]

By "easier to tune", do you mean "physically easier to turn the pins"?

[Jim McConkey]

Actually, not sure now. The finer threads will hold better, so it will probably be a little harder to turn, and therefore it will stay in tune better, but a quarter turn on either should change the pitch the same amount. With geared tuners, you definitely get finer pitch resolution, but I don't think that applies to hitch pins.

[Ian Lynagh]

Yeah, without any gearing, it's just the radius of the pin and the angle that you turn it that will affect what it does to the string tension; I don't see how the thread coarseness can matter.

Well, I suppose technically a coarser thread will move the string closer to the instrument as you tighten it, which will alter the vibrating length slightly. And perhaps another advantage of finer threads might be that it is easier to keep all the tuners and strings at the same height after installing and tuning the strings.

Anyway, I had a look at some other aspects of the kit. It seems to have a 2.5mm front and 2mm back, and I'm guessing that they have prioritised strength over resonance, so I should probably aim for a 2mm or thinner top, in order to get a nicer sound.

The sound hold was also smaller than I'd planned, at around 3.5cm diameter. I think I might reduce the size of mine too, on the basis that it is easier to enlarge later than to make it smaller. I might also try enlarging the one on the kit, and see if I can tell what effect that has.

The kit's bridge is over the solid wood of the bottom of the instrument, rather than over the hollow of the soundbox. I'm guessing that this is again for strength. I tried wedging a small piece of wood under the strings (but over the soundbox), and I thought that this seemed to resonate better, although it also raised the pitch so I can't be certain. So I'm inclined to stick with my plan of putting the bridge over the sound box.

I put the lowest and highest strings on the kit, and managed to tune them to the right notes without breaking either of them, which is encouraging. I measured them as being

• D4, 0.6mm diameter, 26.6cm vibrating length
• E5, 0.1mm diameter, 24.7cm vibrating length

I also got a handful of Galli strings, including the smallest and largest that were available, which I measured as being 0.1mm diameter (0.2mm according to the packet) and 1.3mm (1.35mm according to the packet). I also checked, and even the thickest string fits through the hole in both the Viking and Gewa pins (and so will probably also fit a 5mm Gewa). I think that substituting a 1.2mm string for the 0.6mm string should turn the D4 into a D3, all else being equal, and I certainly don't want to go any lower than that, so it looks like this lyre size should be sufficient. I'm still considering mocking up a 30cm D3 on a simple piece of wood before going further, though, just to see if there are any problems.

In terms of designing the instrument, I realised that I don't have to worry too much about working out what string diameters and lengths I want ahead of time. I can just place the pins so that the strings are nicely laid out, and then if my diameters are off then I can just use different strings than I'd planned.

[Teresa Wiggins]

Hi, following this interesting thread as I'm in the beginning stages of planning a lyre myself.