Double String Debate

[Elettaria]

Does this work? The chart on the left shows the string lengths at the top with the solid lines and the gauges below in the dotted lines, and the chart on the right compares string tension. I’ve also got individual charts for tension, tensile strength ratio and T/L ratio if need be.

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[wil-weten]

Your top strings would already be very thin in nylon. In KF they would be even thinner. I wonder how that would feel to your fingers. Would it cut into your fingers, even if it’s a low tension string?

[Biagio]

These all look OK to me, I’m just kind of wondering why you want to go through so many iterations, when I gave you a perfectly good string design already? Not that I’m bragging but it works ha ha. It is small and compact: I play it lying in bed for goodness’ sakes. From waist to shoulder I am 58cm; if you are shorter, just prop up higher in the pillows or slide down lower:-

OK it would perhaps be 2cm taller than what you posted but geez, not THAT much. If you want it narrower just drop that treble A. Or, heck, don’t leave room for bridge pins and levers (which I did) which will make it even shorter by about 4cm. If narrower you could make the spacing smaller, like your Ardival. My design is spaced at about 1.27cm – make that 1.1cm like the Ardival, then your fingers won’t have to relearn:-)

If you want to keep things really simple….cut out two ‘L’s from about 2cm baltic birch ply and clamp/glue them together. Then just cut out the combined neck-pillar part – piece of cake. Make the two string ribs from some of the scrap 3mm Finnish birch SB material: tapered from 2.5cm at the bass to 1.25cm wide at the treble.

Really, my friend, I think you know all that you need to know at this point except perhaps for minor construction details. Any good wood worker can fill in the blanks. Try to bear in mind that you are not building a big concert quality thing, just a decent sounding small double.

I’m all for players building at last one harp and, yeah, I could draft a full scale model but – my goodness – I’d charge you billable time for that which would cost more than the harp!! Plus I don’t want to; my back hurts, hee hee.

I hardly think it is worth that for you, honestly:-) You know what you’re doing, I think.

Look at what others have done; perhaps, if you want more input, join the Harpmakers Yahoo forum….

Have fun in any case!

Biagio

• This reply was modified 6 years, 3 months ago by Biagio.

[Elettaria]

Avoiding 0.022″ – ah, that’s why I’m not seeing that string anywhere in the UK! Duly changed to 0.025″. That said, I’ve rented a Camac Hermine for quite a while, and the top strings on that seem to be the KF equivalent to 0.022″, so I possibly could cope. I remember being worried that the strings would be bitey, and I think they were fine. Either way, it’s easy enough to switch if I change my mind, at least if I’m using KF. I’ll probably be using the top strings on this more than I use the top few strings on a 34 string harp.

Changing to Biagio’s stringing – believe it or not, this almost doubles the tension on the soundboard, as well as adding 3″ in length, even skipping bridge pins and levers! I really do need to keep it as lightweight and small as possible. I know most people are fine with the lap harps that are generally around, but I’m 4’11” and have severe ME/CFS that hugely affects my ability to lift things. A County Kerry was way too big and heavy for me, and they’re considered fairly small harps. An Ardival Kilcoy is just about OK at 4lb/2kg, and I could manage something a bit taller, which is a relief considering how short Kilcoys are. I manage to get pain flares from playing my lyre some of the time, and that’s only 1.5kg/3lb, although it’s not as comfortable to hold as a harp. So as well as needing to be taller, I’m guessing Biagio’s stringing requires a heavier frame to support it, where my design is only a bit wider than a Waring. That’s also why it only has 20 strings, to keep the size down, along with wanting to keep the extra tuning down as much as I can. I massively appreciate the help and have been studying that stringing chart, along with several other charts, very carefully.

Narrowing the string spacing – I did consider this, but I don’t want additional strings, I think I can handle the size as it is, and if I narrow the spacing I lose soundbox size as well as having to get used to a new spacing, so it didn’t seem worth it.

Speaking of pain, I’m in a lot tonight, the level where it’s getting hard to think straight, so apologies if any of this is muddled or snappish.

• This reply was modified 6 years, 3 months ago by Elettaria.

[Biagio]

Hard to see how KF would be almost 1/2 the tension as Tynex at the same lengths and frequencies! Be that as it may, it is obviously up to you. That’s the fun!

As to the frame: to repeat. the box is 6mm baltic birch ply, the neck-pillar 3.8cm thick.same as the Dusty Ravennas. It does not get much lighter than this.

Rest well, and think about it – that’s fun too.

• This reply was modified 6 years, 3 months ago by Biagio.

[Elettaria]

Oh, I meant the calculations were for nylon throughout, using that magic spreadsheet. I can put in a screenshot tomorrow, that might make more sense. Brain’s a bit fried tonight. Thanks for writing everything in metric, by the way, I appreciate it. The thickness of the timber is what I was planning, so I’m glad that matches. Any idea how narrow I can get away with making it, since I don’t need to leave space for bridge pins or levers? I currently have the pillar about 4cm wide and the neck 4.5cm widening to 6cm at the other end.

Anyway, time for sleep, hopefully. Sympathies to you on the back pain, not fun, is it.

[Biagio]

First, draft it, then you will see how wide it needs to be.

[wil-weten]

As the thinness top of the Camac Hermine KF-strings didn’t bother you and in your case KF would be cheaper than nylon, I would be inclined to put KF-strings on the harp.

I like the sound of KF-strings.

As to the eyelets: beware that if you later decide to use some nylon wound strings, the eyelets must be big enough to let them through.

As to bridgepins. You may skip them if you are sure you don’t need levers, but I heard it’s easier to put strings on when you do have bridgepins. I have no experience in that matter though.

I guess you will be using zither pins? They weigh less than through pins.

[Elettaria]

Wil – Any idea what size eyelet I should grab? Mae has also pointed out I need to make sure I drill the holes bit enough for wound strings, she had to faff around with that when doing the adapted version of her Brittany. Is there a problem with making them all a bit bigger, or do you lose sound or something if the eyelets are a bit on the big side? I think they’re all the same size on my floor harp (I’m renting a Starfish Student at the moment), so there’s plenty of space around the string in the eyelet for the top half of the strings.

Also there will be reaming out some of the zither pins in case of later wound strings, I’m not sure how many of those to do.

Yep, there are some nice zither pins I can get. I know some people are quite keen on them, point out that they work absolutely fine in the construction of pianos, and take less wood out of the neck so that’s good for strength.

Hmm, I’ve put strings on a wire harp with no bridge pins and not had any trouble at the tuning pin end, but brass strings are different to deal with anyway. I know one luthier who doesn’t use them for small nylon harps because he reckons the sound is better without anything to interfere with the string, small harps being harder to get a good sound out of, and he’s really anti-chromaticism so he wouldn’t want people putting levers on his harps later anyway.

(Is your name a joke about Wil Wheaton? Star Trek joke?)

Biagio – that’s the draft in the picture I attached a few messages up. I’ve been sketching the soundbox as well, that’s around on my sewing desk somewhere. Am I better off with two string ribs, then, rather than one used for both courses and placing the courses close together at the soundboard end? I’ve been getting the measurements for the Stoney End double string ribs for comparison.

[wil-weten]

Hi Elettaria, I know practically nothing of harp building. But Biagio does know a lot about harp building plus he has the necessary building experience.
I just happen to be interested in about anything that has to do with harps (and a lot more, but that’s a different topic).

How funny, I didn’t know about the Star Trek Character. Now I like my nick even better! ‘Wil’ is a common Dutch name and also means ‘want or wants to’
In combination with ‘Weten’ it means: ‘wants to know’. I am notorious for wanting to know all kinds of things just for fun…

[Elettaria]

Wil – Cool!

Here is the spreadsheet that goes with the graph I put in a few posts ago. You can see how, between the longer length and thicker gauge, Biagio’s stringing plan comes out around twice the overall tension of mine. There are two totals at the bottom of the tension columns: firstly comparing the total tension for the same nineteen strings on all of them, G up to D, and then the overall tension for all the strings listed (which isn’t the full range on the Limerick, that goes down to tenor C).

The sketch I linked to a few posts further up probably isn’t all that clear, so here are the sizes involved.

It’s on A1 squared paper, 2cm per square. The photo is a touch distorted, it was hard to get the lighting right, but you can look at the grid to see that.

The harp is 65cm (25 1/2″) tall and the soundboard is 62cm (24 1/2″) long. I forgot to measure the depth of the harp while I was in there, but I think it’s about 40cm (15 3/4″). The soundboard is 3mm (1/8″) thick and the soundbox is 5.8cm deep (2 1/4″), using 6mm (1/4″) thick sides and back.

The neck and pillar are 4cm thick, the pillar is about 4cm wide, and the neck varies from 4.5cm to 6cm wide.

The thinking was that this is strung not much more heavily than the Waring, so I’ve sketched it as built slightly more heavily, but still very light. The Waring is made from two single-strung harp frames put together, so it’s all 3.8cm x 3.8cm for the neck and pillar, and then the soundboard is combined with a string rib so that’s different anyway (and by my estimate, about 9cm x 1.2cm, if he didn’t use his usual 1.9cm x 3.8cm). The string lengths are about the same in the middle but generally a little longer for my plan, in order to get a harmonic curve in there.

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[Biagio]

Elettaria, I’ve tried to respond to your questions (twice) but for some reason it keeps being rejected. Beats me as to why, but until the hosts clear this up guess I’m “off the air.”

Biagio

• This reply was modified 6 years, 3 months ago by Biagio.

[wil-weten]

Maybe the sad SPAM-software just allows a limited amount of messages per member? Even if that member has a well respected status?

Because recently one spammer managed to get its spam through and there’s no way to indicate that it is a spam message and it looks like no one is going to remove it…
This is the spammy message that was published a bit more than twelve hours ago…: https://harpcolumn.com/forums/topic/the-announcement-further-reiterates-that-the-clients-can-save/

[Biagio]

Maybe Wil, though I can’t think what was in my post to trigger that. There have been some posters here that I would have banned long ago over on the VHC (grin). Anyhow, once more into the breach:

Zither peg holes: Standard ones will accept up to 0.045″ (1.14mm), Any larger diameter and it will fray; in any case, windings should not extend through the hole.

Eyelets: You should be OK with “medium” sizes and I think it looks better if all are the same size. Up to you, but check that if some are or will be wound the internal diameter is large enough. “Large” sizes may have shafts that will poke through the inside which will cut the strings. So check that too.

I prefer two ribs spaced 5cm apart on center. Be sure to leave enough vibrating surface on the outside (the space between is acoustically dead): about 5cm. This will make the top wider than on a single in total but leave the same finger room.

On comparisons: take a look at %tensile strength too. Much below a minimum of 20% and the string may not sound well unless you use a very light pluck.

[Elettaria]

Yep, I saw that spam post and couldn’t find anywhere to report it to. I also saw Biagio listed as having replied to this topic the most recently, but no sign of his posts when I came to look at it.

Meanwhile I went and reread Evolene’s thread in the triple/double section, and have copied out Biagio’s comments there about string ribs into my notes. I should possibly mock up a soundbox in cardboard again and try to figure out the widest I could handle.

Making the top wider: would I be better off making it 15cm or so all the way down, like Harpsicles? I was originally going to make it 11cm at the top and 21cm at the bottom.

Tensile strength: according to the magic spreadsheet, it dips below 20% for the bottom two strings, going down to 17.6% and 14.7%. It would stay above 20% if I shifted the stringing up a note. (It would have six notes below 20% if I were to drop it a note, as we were talking about when thinking about an offset stringing scheme.) I’ll do that if I have to, but that bottom F would be nice. Is that the sort of thing that benefits from wound strings? I still don’t have a feel for how it all works with wound strings (any good websites on the subject), apart from hearing that they’re great and knowing that they are not terribly cheap due to import costs.

I am still not sure what the measurements of a medium eyelet are, but I will look into that.

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