Steel wire in tension

[greybeard]

Ouch... but interesting.
Thanks, Neil.

[greybeard]

But then the pike jaw sounded great.

[hub]

But then the pike jaw sounded great.

So the story goes. But nobody confirmed it
And impossible to prove:
- no giant pikes.
- no willing maidens.

sadly

[greybeard]

So I'll just have to sit and listen to Sibelius and dream......

[neilw20]

And I will play my tuba. A very temperature sensitive piece of equipment, it is, and British, to boot and 44 years old.

[greybeard]

Neil, the guy in your liquid Nitrogen link is my kind, probably Geof's too. Has problem/question, and sets up an experiment to justify or explore.

John

[hub]

So I'll just have to sit and listen to Sibelius and dream......

A great composer for sure
You know a fair bit of Finnish history. This got 'a bit' off the topic (sorry) but I'm impressed. I have a buddy from the UK who knows more Finnish history than me.

[greybeard]

No, hub, a love of Sibelius plus the ability to quickly read your original wiki quote on the Finnish instrument. I can claim nothing more.
Besides, this is my post so I'll go OT if I want to. It's Christmas, and I'm having one of my usual off the wall ideas !

OK, back on topic.
A piece of plywood with a set of anchor points along one side, and a 1" diam. rail along the other.
Initially, identical weights hung on the end of each wire should produce identical tension, and therefore identical frequency in the strings.
Then run a series of experiments as per Geof's suggestion, changing weights, and use my Korg tuner to compare the results.
I'm not sure about the resolution of the Korg, so can anyone suggest a freeware prog that will turn my pc into a frequency recording meter (ubuntu NOT windoz) ?

[hub]

No, hub, a love of Sibelius plus the ability to quickly read your original wiki quote on the Finnish instrument. I can claim nothing more.
Besides, this is my post so I'll go OT if I want to. It's Christmas, and I'm having one of my usual off the wall ideas !

OK, back on topic.
A piece of plywood with a set of anchor points along one side, and a 1" diam. rail along the other.
Initially, identical weights hung on the end of each wire should produce identical tension, and therefore identical frequency in the strings.
Then run a series of experiments as per Geof's suggestion, changing weights, and use my Korg tuner to compare the results.
I'm not sure about the resolution of the Korg, so can anyone suggest a freeware prog that will turn my pc into a frequency recording meter (ubuntu NOT windoz) ?

Ok Thanks for taking interest on your part

How many strings do you have? A 6 string guitar will create 'a lot' of tension on the neck. You need to multiply the tension by number of strings. And remember that different strings have different tension.
All of those strings are pulling against wood. It takes time & patience to make an instrument. There is no shortcut.
Also, check that the wood you use has dried for at least a minimum of 5 years.

Hub

[greybeard]

Number of strings ? - 43 on this one, probably more on the developed one
No neck, unlike the Mountain or Appalachian Dulcimer !
To get an idea of the instrument, and my favorite youtube clip of a dulcimer player have a look at
http://www.youtube.com/watch?v=egLGPfkj1Gc]Fast Hands - Max ZT - YouTube

If that doesn't work search "youtube fast hands Max ZT

[hub]

Number of strings ? - 43 on this one, probably more on the developed one
No neck, unlike the Mountain or Appalachian Dulcimer !
To get an idea of the instrument, and my favorite youtube clip of a dulcimer player have a look at


If that doesn't work search "youtube fast hands Max ZT

Nice clip, thanks

That's a lot of tension in total. Every string will pull the wood they are connected to. Even a low amount of strings (6 for guitar) will pull & bow wood surprisingly much. With time of course.
When making an string instrument, adjust & let settle for weeks, adjust again & let settle and so forth until it holds the setup.
It just takes time.. There is no work-around as far as I know.

[Geof]

Would fix a few problems but I'm not sure the sound would be that great..

Very difficult to say because music is so subjective. Years ago I managed to get a professional violinist who was getting into making violins to try composites and he became hooked. I have also read accounts of conventional and composite instruments been played to an unseen audience who did no better than random choice in identifying which instrument played what tune. Of course this was between modern instruments; I have no doubt a knowledgeable listener would identify a 'fiberglas' violin compared to a Guaneri or Stradivarius.

[greybeard]

I have just recalled a suggestion of using an energising coil to make all the strings of a guitar vibrate continuously as a speedy method of getting the settling in time drastically reduced.
Or did I dream that ?

Building an equivalent for a 43 string dulcimer would be a challenge, but not too difficult, I think.

[Geof]

......When making an string instrument, adjust & let settle for weeks, adjust again & let settle and so forth until it holds the setup.
It just takes time.. There is no work-around as far as I know.

I bloody great big heavy cast iron frame.

Although come to think of it there may even be a settling period for cast iron because its compression modulus varies with the stress applied.

[Geof]

.....Or did I dream that....

Maybe not. I think this approach is similar in principle to vibratory stress relieving on large weldments.

[greybeard]

Found it - the ToneRite must have been the device I read of.
All I need now is to re-design it for a dulcimer !!!

Following that, I found an interesting discussion on Acoustic Guitar Forum - "ToneRite: Results of a scientific test"
where it appears that the device is a straight forward 60hz vibrator.

[hub]

From an engineering point of view, carbon fiber is a totally superior material compared to wood. Light weight, very strong, stabile (humidity changes does not affect it, temperature changes does very minor effects etc).
In my opinion it would work for any instrument; BUT, the 'old' designs and dimensions are made for wood, which has totally different properties. And yes, for an instrument, it's very subjective to what sounds good and what doesn't
With some design changes, I think carbon fiber instruments will be great some day
Hub

[greybeard]

I suppose one could imagine both frame and "strings" made from carbon fibre

Back off topic - that kantele music on you tube is something else, and am becoming a fan !
Onnellista uutta vuotta

John

[DMF_TomB]

i am a Field Machinist (millwright) who does precision alignment of large machines. We have found (my over 30 years experience and learning from other old timers from data going back over 100 years) that most metal parts subject to tension or compression and their exact alignment measured change especially after the 1st 24 hours.
.
various reasons like fluid (oil / water) on surface moving, surface of metal "the fuzz" under compression and compacting / burnishing, metal stretching and compressing for other unknown reasons.
.
it is normal and happens most of the time. long ago gave up guessing why, it just does most of the time.
.
once had a discussion with an "engineer" how a building moves every day. tried to explain sun comes up, outside steel columns expand from heat, floor beams change level as well as machines sitting on them, interior building columns do not do as they are in the shade. tried to explain a very basic procedure we had over 100 years old where the exterior column can be measured growing relative to interior building columns and measurements over 6 hours can show a 0.030" change on the 2nd story of a building.
.
on another job we have a precision linear rail setup straight within 0.001" per 60" and the next day it was wavy over 0.005". the old timer working with me laughed at the setup. as he figured the sun coming through a skylight would cause the metal to expand relative to the concrete floor holding the rail every foot. as the metal expanded it was longer and the only way it could move longer was to go wavy like a snake. we tried they next day when it was cloudy all day and the rail was straight again.
.
many things move. people often do not bother to measure it or sense it. with precision optics you can easily measure a floor going down from the weight of a 200 lb man and it going back up when he leaves. it has always done this, it is just people often cannot or do not bother to notice it
.
the engineer who had a hard time believing the fundamental laws of the universe did not apply to him because they were not convenient to his schedule got laid off long ago. we fixed many of the problems he left behind.

[greybeard]

Hi Tom, and thanks for your entertaining and informative post.
I'm afraid I'm cursed with an inability to "give up guessing why", but I am learning to live with it.

Happy New Year,

John