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Spring Force

Posted: Mon Oct 05, 2015 6:01 am
by Perdix
Hi,

I know, two odd questions at once....!

Has anybody made an investigation into how much force makes a chanter key 'nice' please?
Also, is the ideal to have each key feel the same? This would make a lot of sense, but many things in life are counter-intuitive.
You could look at a sensible maximum bag pressure, work out the force on any pad and that combined with an allowance for stiction would give a minimum amount of springing needed.
But, there's that counter-intuitive thing again.

I'm wondering if a similar train of thought is suitable for Regulator keys too, although the values may well be different.

Thanks,

Myles

Re: Spring Force

Posted: Tue Oct 06, 2015 5:25 am
by outofthebox
The important thing with the key springs is that they return the key to its stop position quickly and efficiently. Not a lot of spring force is required. But it is important to ensure that the key is moving freely on the pivot (lubricate) and that the sides of the key are not in contact with the wood - or that the gaps do not become filled with dust etc over time.

Re: Spring Force

Posted: Tue Oct 06, 2015 11:42 am
by Perdix
I'm thinking of having a 'play' with an idea, but I don't have an example to hand to see what the actual force is when the keys feel right.
It's a bit like an automotive poppet valve, I suppose - only enough springing to get the job done.
The problem is quantifying how much is just enough! :)

Re: Spring Force

Posted: Wed Oct 07, 2015 5:29 am
by outofthebox
Are you thinking of flat springs or the wound wire coil type?

Re: Spring Force

Posted: Wed Oct 07, 2015 5:58 am
by Perdix
Actually, I'm thinking of torsion springs... I'm not sure if it is going to be practical with the limitations of space in a 'traditional' key block.
Of course, getting really clever, the blocks could contain the windings and the whole arrangement could be made almost invisible and have very little friction. But that complexity is beyond what I am thinking about just at the moment.
My mind gets full of 'what if'..!

Re: Spring Force

Posted: Sat Oct 10, 2015 8:18 am
by MHay
There is a very good series of articles in "The Piper's Review" magazine . If you subscribe you also get access to the back issues with articles on most aspects of pipemaking.
NPU has detailed videos on key making by several pipemakers. Those would be the places to start.

Re: Spring Force

Posted: Fri Oct 16, 2015 6:25 pm
by Perdix
Thanks, I am waiting on my request for access being granted...

Re: Spring Force

Posted: Fri Nov 13, 2015 9:01 am
by billh
For regulators, between 150 and 200 grammes of force seems about right. Less than 100 and the keys will get opened by accident while playing.

Re: Spring Force

Posted: Sun Nov 29, 2015 9:11 am
by Perdix
Thanks Bill.
I have had a great electronic conversation with David Quinn too where the same figures came up. That sort of underlines the 'rightness' of feeling.
Cheers!

Re: Spring Force

Posted: Fri Apr 01, 2016 4:48 am
by billh
Perdix wrote:Thanks Bill.
I have had a great electronic conversation with David Quinn too where the same figures came up. That sort of underlines the 'rightness' of feeling.
Cheers!
In fairness, my figures would have originally come from David Quinn as well. I did make some lighter springs in earlier days, and yes, they did seem too light.