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Topic: Measurement tolerance for scale length and fret positions |
JB Bobbitt
From:
California, USA
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Posted 22 Sep 2018 12:52 pm |
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Hi again. I'm an experienced and proficient woodworker (newbie guitar builder), and I'm well aware of realistic tolerance for measurement for wood specifications. But dimensions I've seen (e.g. StewMac fret position calculator) spec out to +/- 0.001 mm (0.000039 in). This resolution is not realistic in woodworking (it even exceeds the expansion/contraction of a steel ruler).
What spec resolutions are really achievable for scale length and fret position markers?
Thanks a heap,
-jbb |
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Chris Clem
From:
California, USA
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Posted 22 Sep 2018 2:38 pm
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Hi John,I've been down this road. You can lay them out by measurements but it is time consuming and it is easy to make a mistake.I find it much easier to just use a fingerboard that is already laid out to the scale you want use and line it up with the one your making and mark it that way.Or better yet,if it is a common scale length that you don't have just buy a fingerboard from Stewmac and use it as a guide for cutting yours.
Cutting the slots is mostly very easy,but as you go up the fretboard and the frets get closer together it can show if you get one off just a tiny bit.That is why it is always better to use an accurate board to use as a guide for your saw. Hope that helps....Chris |
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Fred Treece
From:
California, USA
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Posted 22 Sep 2018 3:55 pm
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You’re building a lap steel, not a guitar-guitar, right?
Chris’ advice is good, you could just buy a fretboard and glue it your neck. Also keep in mind that the fret markers are...markers, not frets. The steel player uses the fretboard for reference, and his ear for bar placement. A tolerance of .001mm is beyond ridiculous for lap steel. The markers themselves are what, maybe a couple mm thick? |
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Steve Lipsey
From:
Portland, Oregon, USA
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Posted 23 Sep 2018 11:09 am
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And my builder actually changes the equation slightly to compensate for the added typical bowing of the strings when playing higher on the neck...a tiny bit more distance from the middle of the neck up to the bridge than below (not sure exactly where he starts the added space)! (Ben Bonham of Hood River OR). So you can go down a lot of potential rabbit holes in the design process...practical vs. ideal designs...and, of course, there is so much parallax already in how you see the string in relation to the fret, high vs. low frets....so being "accurate" doesn't really mean that the frets are any sort of actual benchmark for playing...
_________________
https://www.lostsailorspdx.com
Williams S10s, Milkman Pedal Steel Mini & "The Amp"
Ben Bonham Resos, 1954 Oahu Diana, 1936 Oahu Parlor |
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L. Bogue Sandberg
From:
Chassell, Michigan, USA
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Posted 23 Sep 2018 6:45 pm
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John,
Your normally achieved tolerances as a good wood worker will be fine. Recently, a non-musician, expert woodworker friend built me a 10 string lap steel from my drawings. We used a trim-to-width, peel and stick fretboard from forum member George Piburn of GeorgeBoards. I just rechecked scale length and 12th fret distance. Both are accurate to something less than 0.5 mm. That's about as accurate as I can measure with a steel ruler and way more accurate than my eyes and ears can ever hope to match!
Enjoy your build!
Bogue |
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James Kerr
From:
Scotland, UK
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Posted 25 Sep 2018 1:17 pm
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John, If your chosen scale length is 23 inches, like mine, then have a look at this Fret Board in my Video, it is 3 octaves long but you can trim this to suit yourself. I can send you a file which will print this out on your Ink Jet at home, all I need is a PM with your email address. It is a copy of an old National design.
https://www.youtube.com/watch?v=KTmg9o1UXOo
James Kerr. |
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Jim Sliff
From:
Lawndale California, USA
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Posted 28 Sep 2018 7:43 pm
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The following site discusses practical application of the "rule of 18" (imprecisely worded since the "rule" extends to thousandths of an inch).
Whether the instrument is fretted for "normal" playing or "steel" playing the rule isn't normally altered - just the tolerance. Compensation for "fretting" is not substantially different from some string vibration, but compensation for fretted instruments (needed because of fretting different strings at different points plus sting construction) is usually done at the saddle.
There are several links to various calculators as well. Most fretted instrument fretboards are made on CIC machines and although the precision may be exceeded by expansion/contraction it's proven to average out well ("rulers" are very rarely used in 6-string luthiery and preslotted fretboards can be ordered in a variety of materials/lengths/widths/scale lengths.
It'd seem to make the most sense to just order a preslotted board rather than go through the hassle of making one.
https://www.liutaiomottola.com/formulae/fret.htm
_________________
No chops, but great tone
1930's/40's Rickenbacher/Rickenbacker 6&8 string lap steels
1921 Weissenborn Style 2; Hilo&Schireson hollownecks
Appalachian, Regal & Dobro squarenecks
1959 Fender 400 9+2 B6;1960's Fender 800 3+3+2; 1948 Fender Dual-8 Professional |
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James Kerr
From:
Scotland, UK
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Posted 29 Sep 2018 1:50 am
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| Jim Sliff wrote: |
The following site discusses practical application of the "rule of 18" (imprecisely worded since the "rule" extends to thousandths of an inch).
Whether the instrument is fretted for "normal" playing or "steel" playing the rule isn't normally altered - just the tolerance. Compensation for "fretting" is not substantially different from some string vibration, but compensation for fretted instruments (needed because of fretting different strings at different points plus sting construction) is usually done at the saddle.
There are several links to various calculators as well. Most fretted instrument fretboards are made on CIC machines and although the precision may be exceeded by expansion/contraction it's proven to average out well ("rulers" are very rarely used in 6-string luthiery and preslotted fretboards can be ordered in a variety of materials/lengths/widths/scale lengths.
It'd seem to make the most sense to just order a preslotted board rather than go through the hassle of making one.
https://www.liutaiomottola.com/formulae/fret.htm |
Jim, very informative article but a Lap Steel or Pedal Steel is not a fretted Instrument and does not require Slots or Frets, nor do they require adjustable Saddles.
JK. |
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George Piburn
From:
The Land of Enchantment New Mexico
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Posted 29 Sep 2018 6:41 am Fretboards
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Hello from GeorgeBoards Manufacturing
Just in the short time this thread inquiry has been live we have already made a few dozen FBs. For Sale.
Our software goes out to 6 decimal points , we stop at 4 points , and our CNC Machine and CNC Lasers stop at .000 anyway.
The Suggestion of buying parts to assemble your lap steel is our advise too.
Mr. Kerr's printout is a great low cost way to get one going, local plastic shops can fabricate a plexi over-strate.
The Forum has several Fretboard makers to start with.
I have new Laser etched wood FB's for under 20 dollars.
We make Plexi etched clear - peel n stick - CNC Milled Wood for Inlay lines and dots set up for EdgeBanding --
all reasonably priced and can make any scale or outside shape.
This commentary is is to help folks with their DIY projects, not so much as some kind of big bucks sales pitch.
_________________
GeorgeBoards S8 Non Pedal Steel Guitar Instruments
Maker of One of a Kind Works of Art that play music too.
Instructional DVDs
YouTube Channel |
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Bill Groner
From:
QUAKERTOWN, PA
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Posted 29 Sep 2018 7:23 am
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I make my fretboards using a Digital Readout on a milling machine. They are right on to the thousandths of an inch. That being said, it is more important to have a good ear, than it is to see that fret. Chances are you will be off no matter how good your eye is. Lap steel I think is more of an audio thing than a visual thing. Frets are great as a guide to get you close.........kind of like lines on the road.
_________________
Currently own, 6 Groner-tone lap steels, one 1953 Alamo Lap steel, Roland Cube, Fender Champion 40 |
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