StewMac tools

Scale Length

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Scale Length

Postby marc lavertu » Fri Sep 02, 2016 9:23 am

Hi!

I'm working on Firebird guitar project. Long story short, I receice the wrong fingerboard twice. It's a 25.5 scale length instead of 24,75.

My question is, can I modify my plan and change the scale lenght. I heard about the tension on the neck. This is a big concern because of the scarf joint.

The body is still untouched. So I can change whatever I want. The fingerboard design is a big part of the all project so I really want to use this one.

All the informations you have will help me, again, to make this project a great guitar to use!

Thank you!

Marc
Last edited by Jim McConkey on Mon Sep 05, 2016 12:50 am, edited 1 time in total.
Reason: Fixed misspelled title
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Re: Sacle lenght

Postby Chris Richards » Fri Sep 02, 2016 9:36 am

I don't see any problem, just move the bridge back by 3/4 inch and reposition the bridge pickup back a little other than that I can't see a problem at all. The string tension will be a little more but there's no need to modify the neck at all.

Here's a picture of a 25.5 scale firebird type guitar I built a while ago, also has 24 frets.
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Re: Sacle lenght

Postby Chris Richards » Fri Sep 02, 2016 9:41 am

Actually, I guess you may have to have the fretboard extend a little passed the end of the neck tenon to get all the frets in so to speak but I wouldn't attempt to modify where the top nut is.
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Re: Sacle lenght

Postby Gordon Bellerose » Fri Sep 02, 2016 2:29 pm

As long as the bridge mounting holes have not been drilled, you can place it anywhere you want.
If it needs to move back to make the scale work there should be no problem.
I would assemble the neck and attach it to the body. Then measure from the nut to the bridge position.
Stewmac.com has a scale measurement tool on their website.

I wouldn't worry about extra tension because of scale length changes. Any well constructed scarf joint will take the small amount of extra tension.
I need your help. I can't possibly make all the mistakes myself!
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Re: Sacle lenght

Postby Dan Smith » Sun Sep 04, 2016 10:20 pm

Marc,
Gibson's actual 24.75" scale length can measure 24.75", 24.625", or 24.562".
They call them all 24.75".
My son's SG measures 24.56".
The fretboard you received is correct - at least for an SG.
This has caused me some headaches too.
Dan
Ever-body was kung fu fight-in,
Them kids was fast as light-nin.
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Re: Scale Length

Postby Freeman Keller » Mon Sep 05, 2016 12:35 pm

marc lavertu wrote:Hi!

I'm working on Firebird guitar project. Long story short, I receice the wrong fingerboard twice. It's a 25.5 scale length instead of 24,75.

Marc


Marc, do you have a neck and fretboard that are 25.5 or just the fretboard and you are going to make a neck for it?

I'm not very knowlegable about Firebirds but my recollection is that they were thru neck - is that what you plan to build? Assuming the neck to body joint is at the 16th fret (as I said I'm not a Firebird expert), then a 24.75 scale neck would have the nut 14.920 inches from the 16th. To make that a 25.5 inch neck you need to lengthen the neck so the nut is at 15.380. (numbers were obtained with the StewMac fretboard calculator)

http://www.stewmac.com/FretCalculator

Next you will need to move the bridge and saddle so they fall at the scale length plus and compensation you are going to add - normally about 1/16 for the high E and 3/16 for the low (the StewMac calculator will give you this also). Just shift your bridge to the new location.

Lastly you will probably want to move the pickups slightly - space the neck pup away from the end of the fretboard by the thickness of the mounting ring (plus a hair) and move the bridge pup so it's the same distance from the bridge as in the 24.75.

I assume that you are building from some sort of plans - get a copy of them at Kinkos and lay out your longer neck and bridge location to make sure everything is correct - that will help you a lot when it comes time to carve the neck.

As far as the scarf joint - your guitar will have slightly more string tension than a 24.75 (tension goes up with the square of scale length) but it will be insignificant at the nut. I use scarf joints on all my guitars including a very long scale 12 string - it is a much stronger joint than the way Gibson and other saw their headstocks.
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Re: Scale Length

Postby Michael Lombardi » Wed Sep 28, 2016 9:01 am

I'm building a screw ball guitar, sort of a small travel guitar. the body looks like a violin, but has a round sound hole, i needed a shorter neck to go with little body, so i used fret calculator and came up with a 23" scale length, i placed the bridge were i wanted it, then made the fret board, then made a 59 gibson neck a 1 5/8 shorter. and my own head stock design. also i make all my necks i piece. course my wood is free from my land. cherry, walnut, maple, cedar, hickory. i include hickory because i plan to make a Tel. style guitar out of hickory. a true axe.
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