Scale length question

[thebassbuilder]

I am wanting to build a short scale bass. I am saying it will be for my two young boys to learn on but I secretly want one anyway, so good excuse to build one. I wanted to know if I can take a fingerboard I have been wanting to use for some time. It is a great looking purple heart but I had slotted it for a different build years ago at 34". I wanted to know if my thinking is correct. Could I chop off fret 1 the F note on the E string. If I do this will the new scale length be the distance from the new nut position to the new 12th fret then double that length for the scale length?

 

[ctmullins]

Yep. 34" minus the first fret is very very close to 32". Chop off two frets and you're around 30".

I do this with 35" LMII slotted boards to get a 33" board.

 

[thebassbuilder]

Thanks for the reply and that is a great idea on using a 35" for a 33".

 

[Scoops]

You can use StewMac Fret calculator to double check your numbers.

http://www.stewmac.com/FretCalculator?gclid=CIrZ6dycpMMCFRMbaQoddW0A3g

Doing a quick calc....your 12th fret will be 0.046 too long

But all you would have to do is reposition the bridge a bit

 

[pilotjones]

You can use StewMac Fret calculator to double check your numbers.

http://www.stewmac.com/FretCalculator?gclid=CIrZ6dycpMMCFRMbaQoddW0A3g

Doing a quick calc....your 12th fret will be 0.046 too long

But all you would have to do is reposition the bridge a bit

I don't know what numbers you're checking, but that's not correct.

Cutting off the first fret, and making the the former first the new zero or nut, the former 2 the new one, the former 13 the new 12 etc. will work perfectly, and with keeping the same bridge line position.

It's the same as putting a capo on a guitar.

Just start with a fretboard with no fret markers if possible, to make your work easier.

 

[scourgeofgod]

You can use StewMac Fret calculator to double check your numbers.

http://www.stewmac.com/FretCalculator?gclid=CIrZ6dycpMMCFRMbaQoddW0A3g

Doing a quick calc....your 12th fret will be 0.046 too long

But all you would have to do is reposition the bridge a bit

I don't know what numbers you're checking, but that's not correct.

Cutting off the first fret, and making the the former first the new zero or nut, the former 2 the new one, the former 13 the new 12 etc. will work perfectly, and with keeping the same bridge line position.

It's the same as putting a capo on a guitar.

Just start with a fretboard with no fret markers if possible, to make your work easier.

Technically you're both right, according to the fret calculator it will be slightly off from a perfect 32" scale, but everything should still intonate fine without moving the bridge. It will be a 32"+change scale.

 

[Scoops]

I don't know what numbers you're checking, but that's not correct.

Cutting off the first fret, and making the the former first the new zero or nut, the former 2 the new one, the former 13 the new 12 etc. will work perfectly, and with keeping the same bridge line position.

It's the same as putting a capo on a guitar.

Just start with a fretboard with no fret markers if possible, to make your work easier.

This is 3rd grade math
Let's review shall we?

The original scale length is 34"
If the the owner cuts the fingerboard off the at the first fret, He will cut off how much?

1.908....Good

If we we to now look at the distance left from the new first fret to the new twelfth fret what is the distance?
Let see, that would be 17.594 - 1.908 = 16.046

On a 32 inch scale where is the 12th fret?

16 inches

16.046 - 16 = .046

Remember....you have to show your work

 

[reverendrally]

I built one for my son with 28" scale. He's still playing it now. Works surprisingly well...

http://www.talkbass.com/threads/2-string-short-scale-for-a-little-guy.822529/

 

[Geoff St. Germaine]

This is 3rd grade math
Let's review shall we?

The original scale length is 34"
If the the owner cuts the fingerboard off the at the first fret, He will cut off how much?

1.908....Good

If we we to now look at the distance left from the new first fret to the new twelfth fret what is the distance?
Let see, that would be 17.594 - 1.908 = 16.046

On a 32 inch scale where is the 12th fret?

16 inches

16.046 - 16 = .046

Remember....you have to show your work

The problem with your math is that cutting the first fret off of a 34" scale fretboard results in a fretboard with a 32.092" scale, not 32" scale. The bridge is not out by 0.46", it is in the proper location, as pilotjones stated.

I don't think anyone needs to try to hand out 3rd grade math tutorials when they don't know the background of their audience. It's needlessly arrogant.

 

[Scoops]

The problem with your math is that cutting the first fret off of a 34" scale fretboard results in a fretboard with a 32.092" scale, not 32" scale. The bridge is not out by 0.46", it is in the proper location, as pilotjones stated.

I don't think anyone needs to try to hand out 3rd grade math tutorials when they don't know the background of their audience. It's needlessly arrogant.

If you read what I post, I indicate that the 12th fret is out by .046. I didn't say the bridge was out by .046. I am fully aware of the fact that the new scale length is 32.092.

I would also argue that bridge placement should be reviewed vs the gauge of the strings being used. There is potential for the .092" to be out of range of the travel of the bridge saddles.

Sorry if I came off as arrogant, but when someone tells me I'm wrong, and in a manner I thought it needlessly arrogant, without really supporting thier opinion, gets my dandur up! Especially in light of the fact that I pointed the OP in a direction to help himself.

A simple statement like PJ indicating that "Hmmm, how'd you get that Scoops"? would have been way more in the spirit of things.

My $0.02

 

[Geoff St. Germaine]

I read your post. I am not clear on why you think the 12th fret is out by 0.046". The scale length with the first fret cut off is 32.092" and the 12th fret for this needs to be at 16.046". When you cut a 34" scale board at the first fret, the scale is 32.092" and the 13th fret from the 34" scale becomes the 12th fret on your new scale length. The 13th fret was 17.954" from the nut so when you cut off the 1.908" length you reduce this distance to 16.046". The bridge and 12th fret are still properly positioned (capo analogy). Your intonation will likely need an adjustment, but that doesn't impact bridge placement.

 

[ctmullins]

This might be an instance of technical correctness versus pragmatism. It is true that a 32" scale length is not the same as a 32.092" scale length. But for all practical purposes (including bridge placement), it's negligible.

 

[Scoops]

I read your post. I am not clear on why you think the 12th fret is out by 0.046". The scale length with the first fret cut off is 32.092" and the 12th fret for this needs to be at 16.046". When you cut a 34" scale board at the first fret, the scale is 32.092" and the 13th fret from the 34" scale becomes the 12th fret on your new scale length. The 13th fret was 17.954" from the nut so when you cut off the 1.908" length you reduce this distance to 16.046". The bridge and 12th fret are still properly positioned (capo analogy). Your intonation will likely need an adjustment, but that doesn't impact bridge placement.

Allow me to rephrase

I have a 34" fret board

I cut off the 1st fret such that I get a new scale length. The new scale length is 32.092
If the bridge is located at the 34" location, and remains unadjusted from a 34" scale, the 12th fret will be out of adjustment (as well as all the rest of the frets)

To get the 12th fret to ring true (let's not get into the faults of equal temperment), the bridge saddle will need to get adjusted. That distance will require the saddle to move .092 away from the 12th fret. There may not be enough room left in the bridge for this extra travel.

If the OP is building a 32.092" scaled bass, I would recommed building it that way. Granted .092 is very little distance, a job worth doing is worth doing right.

 

[scourgeofgod]

Allow me to rephrase

I have a 34" fret board

I cut off the 1st fret such that I get a new scale length. The new scale length is 32.092
If the bridge is located at the 34" location, and remains unadjusted from a 34" scale, the 12th fret will be out of adjustment (as well as all the rest of the frets)

To get the 12th fret to ring true (let's not get into the faults of equal temperment), the bridge saddle will need to get adjusted. That distance will require the saddle to move .092 away from the 12th fret. There may not be enough room left in the bridge for this extra travel.

If the OP is building a 32.092" scaled bass, I would recommed building it that way. Granted .092 is very little distance, a job worth doing is worth doing right.

.092 is less than a tenth of an inch though, most bridges have more than enough space in their "saddle travel" to accommodate such a minimal distance. If the rest of the bass is being built from scratch it wouldn't hurt to add the .092, but in all actuality it should be fine either way.

 

[Geoff St. Germaine]

Allow me to rephrase

I have a 34" fret board

I cut off the 1st fret such that I get a new scale length. The new scale length is 32.092
If the bridge is located at the 34" location, and remains unadjusted from a 34" scale, the 12th fret will be out of adjustment (as well as all the rest of the frets)

To get the 12th fret to ring true (let's not get into the faults of equal temperment), the bridge saddle will need to get adjusted. That distance will require the saddle to move .092 away from the 12th fret. There may not be enough room left in the bridge for this extra travel.

If the OP is building a 32.092" scaled bass, I would recommed building it that way. Granted .092 is very little distance, a job worth doing is worth doing right.

I'm sorry, but this is incorrect. The 12th fret is still in exactly the correct location. This is a function of the 12th root of 2 method of calculating fret locations. Each fret location is 1/(2^(1/12)) of the remaining scale from the previous fret. This is why a capo works.

34" scale - chop of at first fret - new scale is 32.092". Bridge remains in the same location.

This requires the 12th fret to be 16.046" from the nut.

34" scale - 13th fret is 17.954" from the nut. 13th fret becomes the 12th fret when you chop off the board at the first fret.

Chop board at first fret - scale length reduces by 1.908". This means the 13th fret (now the 12th) is at 17.954" - 1.908" = 16.046" from the nut, which is exactly where it should be.

If you go to something like fretfind, you can plug in the scale lengths and it will display the distance to nut and bridge and perhaps this will more easily demonstrate that the bridge position and 12th fret position are correct when you chop off an entire fret position (or even multiple positions).
http://www.ekips.org/tools/guitar/fretfind2d/

 

[Scoops]

Morale of the story: Play fretless

 

[BassFishingInAmerica]

I've actually found this thread highly entertaining. Should I be concerned for my mental state? Or should I just become best buds with Sheldon Cooper?

 

[potomac]

The 12th fret is half way of the scale.

If the scale length total is 0.092" longer then a 32" scale, it means 0.046" on the zero fret and 0.046 on the bridge side, according to a 32.000" scale. (1.16 mm)

Of course, according to a 34.000" scale there is much more difference. Thats the reason why you have to change the body size, the position of the pups and the position of the bridge according to a 34". That all makes sense to me.

I'm planning a 30" Ripper/Grabber, so all the sizes and positions are scaled to 88%. That means a lot of thinking about shrinking. Some parts are easy to shrink, but others are impossible. The whole project has to be balanced to get a bass design that is nice for the eyes, well intonated and good sounding.

Back to the 32.092" scale- To get a clue of the final design, draw the body shape on a piece of paper. Build a template of a 30.092" neck, lay it on the body shape and find a place for it. Now you can play with the positions of all parts till you find your best design. Sometimes you have to change the body size to get a harmonic look.

Or use a CAD Sofware

 

[iiipopes]

This is 3rd grade math
Let's review shall we?

The original scale length is 34"
If the the owner cuts the fingerboard off the at the first fret, He will cut off how much?

1.908....Good

If we we to now look at the distance left from the new first fret to the new twelfth fret what is the distance?
Let see, that would be 17.594 - 1.908 = 16.046

On a 32 inch scale where is the 12th fret?

16 inches

16.046 - 16 = .046

Remember....you have to show your work

You did not show all of your work. If the nut to the first fret of a 34 inch standard scale fingerboard is chopped off, and the fingerboard was slotted according to the standard exponential "equal" twelve frets to the octave, then the distance from the nut to the first fret slot is:

34 - [34 / 2^1/12] which is approximately equal to 1.9083 (rounded to the thousandth), as set forth above.
Then subtracting the 1.9083 from 34 leaves the resulting new scale length as approximately 32.0917, NOT 32.

Divide that number by two and you get approximately 16.046 (rounded to the thousandth), as the distance from the "new" nut to the "new" twelfth fret. This is correct.

To double check the math, then take 16.046 and multiply it back by 2^1/12, which is approximately 1.0594631, and you get 17, which is, of course, one-half of the longer 34 inch scale, where the "old" twelfth fret is, as we all know.

Since these computations involve exponential functions, this is more of a junior high math situation than a third grade situation.

 

[Son of Wobble]

You did not show all of your work. If the nut to the first fret of a 34 inch standard scale fingerboard is chopped off, and the fingerboard was slotted according to the standard exponential "equal" twelve frets to the octave, then the distance from the nut to the first fret slot is:

34 - [34 / 2^1/12] which is approximately equal to 1.9083 (rounded to the thousandth), as set forth above.
Then subtracting the 1.9083 from 34 leaves the resulting new scale length as approximately 32.0917, NOT 32.

Divide that number by two and you get approximately 16.046 (rounded to the thousandth), as the distance from the "new" nut to the "new" twelfth fret. This is correct.

To double check the math, then take 16.046 and multiply it back by 2^1/12, which is approximately 1.0594631, and you get 17, which is, of course, one-half of the longer 34 inch scale, where the "old" twelfth fret is, as we all know.

Since these computations involve exponential functions, this is more of a junior high math situation than a third grade situation.

Lost me at "math." I'll just take a guitar off the rack, cheers.