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Changing scale length 25.4" to 24.9" problems?
http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=19240		 Page 1 of 1
Author:  John Hale [ Sat Oct 18, 2008 5:50 pm ]
Post subject:  Changing scale length 25.4" to 24.9" problems?
Guys I'm building a guitar to kinkheads plans and adapted for a bolt on neck. The plans a for a 25.9" scale length joining the body at the 14 fret. I've measured it out and it I make the scale length 24.9" and join at the 13th fret the saddle falls in roughly the same place over the bridge patch.

My are there any concieveable problems doing this? And Tonally how would it alter the sound? I'm hoping it'll mellow it and give a more bassey tone to the guitar.

Advice please guys

Thanks

John
Author:  bruce bennett [ Sat Oct 18, 2008 8:59 pm ]
Post subject:  Re: Changing scale length 25.4" to 24.9" problems?
Admitedly, I don't built that many Acoustics.. but I've built a substantial amount of electrics and have changed scales mid-build many times.

It's been my experience that if your bridge is still located in the same ,or not more than an 1/8th" from the original location the original scale called for, that there will be very little tonal change in the box itself. at least nothing that some brace work couldn't compensate for,, and honestly changeing to a bolt neck design has already altered the total qualities a great deal more than the change your proposeing. but thats JMHO.

changeing the scale causes string tension changes, and THAT can have a very pronounced effect on overall tone.. the upside is that you "should" be able to balance this out simply by changeing string gauges.

It's possible that if you built two guitars as close to "alike" as possible with the exception of the scales.. that you will note differences between them rather easily.. but then again. do any two guitars EVER sound exactly alike?

final note..

13 is unlucky or haven't you heard..? wow7-eyes

:lol:
Author:  Howard Klepper [ Sun Oct 19, 2008 12:53 pm ]
Post subject:  Re: Changing scale length 25.4" to 24.9" problems?
I had a friend years ago who we called "kinkhead." He had really wiry hair.
Author:  Mike Collins [ Sun Oct 19, 2008 2:39 pm ]
Post subject:  Re: Changing scale length 25.4" to 24.9" problems?
John;
Bass responce is not totaly dependant on the scale length!
top thickness,brace flexibility ,box size !

You should be fine with the smaller scale & the 13th fret joint-just take your time !
Listen to the box when it's together !
if it's tight (treble responce with no warmth)
Then you may need to loosen things up a bit!
But if it's boomy with not to deep a tone your fine!
That's one on the ways i tune my guitar boxes-listening to them!!
Mike

[:Y:]
Author:  TonyKarol [ Sun Oct 19, 2008 4:28 pm ]
Post subject:  Re: Changing scale length 25.4" to 24.9" problems?
Well, unless the bridge plate is pretty big, which it might be, the math doesnt work out so close, as in roughly the same spot, unless the definition of roughly is pretty big ... here is how I see it:

25.4 scale, 14th fret, from the joint to the saddle, no comp, in metric, gives 645.16mm-357.8 = 287.36mm (full scale - minus nut to 14th = neck joint to saddle)

24.9 scale, no comp, 13th fret, 632.46 - 334 = 298.46mm

Thats a difference in saddle position of over 11mm - thats about 7/16 inch. I wouldnt call that roughly the same. Check the saddle position relative to the bridge plate again, it still might work for you depepnding on the size of it.
Author:  John Hale [ Sun Oct 19, 2008 4:58 pm ]
Post subject:  Re: Changing scale length 25.4" to 24.9" problems?
Mike thanks for the vote of confidence its only your encouragement that's got me this far and Tony I'll run the measurements again and double check thing is I've started an evening class where the teacher has quite set ideas and changing the scale length halfway through a build seem an anathema to him. Also mike I've been told by someone at my folk club who repairs guitars and like very light strings that it's a very responsive box and shouldn't have more than 11s or 12s on it as I like heavier gauges normally. I'm just hoping as he likes a trebly sound that mine won't be another reason why I thought to adjust the scale length

Just as an aside the body joint doesn't have to be on a fret does it? Could I just make the scale length fit?

Cheers guys this place enthuses me and I seem to be learning a great deal

John
Author:  Mike Collins [ Sun Oct 19, 2008 5:10 pm ]
Post subject:  Re: Changing scale length 25.4" to 24.9" problems?
Thanks John;
First there are NO set rules as to what fret is at the body joint or if it's slightly inside the body line or outside!
I've made 12,13 &14 fret to the body necks!
Plan the guitar according!!!!
I prefer body joint fret to be outside-just so a player can get to it easier!

Nothing wrong with 12's!!!
95% of the steels I make the client asks for a guitar they can use with 12's and get a great tone & volume!
They are easier to play on!
And sound great if the guitar is made to be optimum with 12's!!
It's all in how you make the guitars!!!!!!!!

Mike [:Y:]
Author:  TonyKarol [ Sun Oct 19, 2008 5:20 pm ]
Post subject:  Re: Changing scale length 25.4" to 24.9" problems?
Absolutely, Mike is on the same wavelength .. if you are making the guitar, there are no rules as to what the neck joins the body at. Just put the bridge (and bracing) in the correct spot.

Using the numbers I have above, assuming the bridge is in the same spot as with a 25.4 scale, with 287.36mm of the scale on the body, changing to a 24.9 scale puts the neck joint 5.5mm south of the 14th fret (towards the 13th fret) -so its a 13 and a half fret (or so) guitar !!!! Go for it .
Author:  John Hale [ Sun Oct 19, 2008 5:24 pm ]
Post subject:  Re: Changing scale length 25.4" to 24.9" problems?
You all know I'm nuts and play 14s I was always told the fatter the string the better the tone and also noticed older played moving down the gauges once they started to get to 70 so I started on 13's no probs as a first restring on my old EKO and it worker I got a better tone from it so when I saw 14s advertised I jumped to them and didn't notice any difference and when I got my first all solid jumbo on the first change there better tone again, since I've been lurking here I've discovered that that is due to an over thick top more than anything else plus a little over bracing too, trouble is now I take a while to adjust to lighter strings and accidentally bend them for the first few minutes :lol:
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