Engineering question.....overstressed axle?

Erv Niehaus · Post by **Erv Niehaus** » 15 Dec 2016 11:23 am

How high is up?

Georg Sørtun · Post by **Georg Sørtun** » 15 Dec 2016 11:25 am

The correct answer is: how high do you want it to be

Erv Niehaus · Post by **Erv Niehaus** » 15 Dec 2016 11:27 am

Just high enough so it doesn't over stress the axle.

Georg Sørtun · Post by **Georg Sørtun** » 15 Dec 2016 2:59 pm

Then make it so

Erv Niehaus · Post by **Erv Niehaus** » 15 Dec 2016 3:04 pm

So what?

Georg Sørtun · Post by **Georg Sørtun** » 15 Dec 2016 3:11 pm

That's right...

Erv Niehaus wrote:So what?

Paddy Long · Post by **Paddy Long** » 18 Dec 2016 6:03 pm

I currently have the changers out of my 86 MCI welded frame PSG - and in bits on my bench -- after 30 years of constant playing this guitar exhibits almost no wear in either the changer fingers or the axle, just a little on the finger tops from string wear. The axle looks to be the same size as most other modern guitars and once I cleaned all the gunk off it and polished it up a little it look like new. (same with the fingers)
So I would be surprised if there was enough of an extreme load on the changer axle to cause any type of flex/or binding etc - unless it was made out of some inferior material.

Georg Sørtun · Post by **Georg Sørtun** » 18 Dec 2016 7:42 pm

Given that 1 cent detuning of a plain 6th string will occur with as little as 0.012mm (0.00047in) flexing of the axle (or anywhere in the mechanics holding the strings in tune), binding in the changer caused by flexing will never be a problem since even the weakest changer axle won't bend enough for that to happen.

The problem with too weak changer axles is that any flexing is distributed unevenly along the strings - most on center strings and hardly any on outer strings. All detuning on outermost strings is caused by flexing elsewhere in the mechanical parts and connections holding the strings in tune.