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Topic: Lap Steel with 24" Scale |
Roger Hinton
From:
Louisiana, USA
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Posted 21 Feb 2014 5:09 pm |
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Hi all,
I have been rebuilding a lap steel that my Dad made several years ago. It has a 24" scale, but the fret-board will not work with the changes I've made.
I looked up the formula to calculate it myself, but I would like someone who knows more about the proper scale and alignment to check my math before I print out a final fret-board design for it.
Below is an image of the spreadsheet. I gave up trying to insert a text or html version...
Thanks
I took out the image to save band width...
_________________
Roger
It's all relative; eventually...
Last edited by Roger Hinton on 22 Feb 2014 7:12 pm; edited 2 times in total |
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David Venzke
From:
SE Michigan, USA
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Posted 21 Feb 2014 5:22 pm
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Hey, Roger,
You could have saved yourself all that math by using a fret calculator, like the one at Stew-Mac.com:
http://www.stewmac.com/freeinfo/Reference/Calculators/i-fretcalc.html
You'll find that your math is off somewhat. With a 24-inch scale, the 24th fret would be located at 18 inches.
-Dave
P.S. I generally convert my scale length to millimeters and then calculate that way for greater accuracy when I lay it out.
Last edited by David Venzke on 21 Feb 2014 5:31 pm; edited 1 time in total |
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Roger Hinton
From:
Louisiana, USA
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Posted 21 Feb 2014 5:28 pm I could have...
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I really like a challenge... The web is so full of garbage these days you can never be too careful with downloads. I should know, I work on computers for a living...
I plan to print out a full scale photo quality image at 2400 dpi and cover it with clear Plexiglas. I want to make sure it is aligned properly.
_________________
Roger
It's all relative; eventually... |
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David Mason
From:
Cambridge, MD, USA
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Jouni Karvonen
From:
Helsinki, Finland
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Roger Hinton
From:
Louisiana, USA
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Posted 22 Feb 2014 6:16 am It Figures...
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Well, thanks for the replies. Using the calculators at the links provided I see that my numbers are off a bit. I just don't get why if I do the math myself it doesn't add up correctly...if rounded to the nearest thousandth...
_________________
Roger
It's all relative; eventually... |
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Rick Aiello
From:
Berryville, VA USA
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Posted 22 Feb 2014 12:46 pm Re: It Figures...
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| Roger Hinton wrote: |
| Well, thanks for the replies. Using the calculators at the links provided I see that my numbers are off a bit. I just don't get why if I do the math myself it doesn't add up correctly...if rounded to the nearest thousandth... |
The Rule of 18 ( well, of 17.817154) ... Is a "shortcut" for the following equation:
Distance from nut to Fret 1 = Scale Length - (Scale Length / twelfth root of 2)
Ex: For a 24" scale ....
Distance from nut to Fret 1 = 24.00 - (24.00 / 1.0594.. ) = 1.347"
.........................
In your spreadsheet ... It should go:
X = 24.000
F= 24.000 / 17.817154 = 1.347 (distance from face of nut to fret 1)
Therefore ... 24.000 - 1.347 = 22.653 ... The "new" scale length
Then ...
X = 22.653
F= 22.653 / 17.817154 = 1.271 (distance from fret 1 to fret 2)
Therefore ... 22.653. - 1.271 = 21.382 ... The "new" scale length
Then ...
X = 21.382
F = 21.382 / 17.817154 = 1.200 ( distance from fret 2 to fret 3)
Therefore ... 21.382 - 1.200 = 20.182 ... The "new" scale length
Then ....
X = 20.182
F = 20.182 / 17.817154 = 1.133 ( distance from fret 3 to fret 4)
Therefore ... 20.182. - 1.133 = 19.049 .... The "new" scale length
Then ...
X = 19.049
F = 19.049 / 17.817154 = 1.069 ( distance from fret 4 to fret 5)
Therefore ... 19.049 - 1.069 = 17.980 ... The "new" scale length
Etc, etc, etc
Somewhere in your spreadsheet, something went wrong in the first few calculations ... And the error compounded itself ...
Hope this helps ...  |
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Bill Hatcher
From:
Atlanta Ga. USA
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Posted 22 Feb 2014 1:16 pm
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about 30+ years ago i bought an 24" machinist rule that is graduated in 4 different fractions.....one being 1/100ths of an inch. i have the old hideo kamimoto repair book that has a bunch of fret scales all done. i just lay the rule on the edge of a freshly jointed fret board and swing the lighted magnifier over and just put a scribe at each fret reading from the distance from the nut column. then i deepen it with a razor knife and then move to the radial arm saw where i have a blade that i took to a saw sharpening place and had ground down to .020. easy to match the thin blade up with the scribe mark. here is a pic of cutting some slots.
here is a simple fret calculator. man this is easy! just put in your scale and bam!
http://www.harpkit.com/category/fretcalc.html |
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Roger Hinton
From:
Louisiana, USA
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Posted 22 Feb 2014 7:02 pm Final Result
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Just wanted to share the final result of all that math and headache for nothing...
Thanks for the posts of fret calculators. That really saved the day.
----
All of the gold parts look 3 dimensional in the full size image. The inlays look sunken down and the frets look raised up... I hope it looks good when installed anyway...
Oh... And I found the error in the math...
It was an ID-10T error
_________________
Roger
It's all relative; eventually... |
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