Straight Edge for Luthiers Tool, Martin, Guitar Neck, Notched, 24.90 and 25.40 Scales


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Straight Edge for Luthiers Tool, Martin, Guitar Neck, Notched, 24.90 and 25.40 Scales


Description - Manufactured in the United States this straight edge can be used for any 24.90 or 25.40 scale instruments. It's made from strongest tempered aluminum we can find (6061-T65 tempered) and measures about 1.5 x 18.5 inches and is 1/8 in. thick aluminum. It has the 24.90 scale on one side and the 25.40 scale on the other side for Martin style guitars or any instrument with 24.90 or 25.40 scales. These are manufactured in North Carolina, USA. We ship from three locations in NC, OH, and sometimes from our delivery truck for the most rapid delivery possible.

Some features of our scales include:

1. Free shipping and lower cost.
2. Higher grade Aluminum.
3. Round Notches instead of Square Notches.
4. "Offset Scale" for higher compatibility.
5. Best information on compatibility.
6. Temperature Declaration for better accuracy.
7. Declared hardness rating of T52.
8. Ours in made in NC, USA preventing the use of any foreign child labor in this product.
9. Use green energies and recycled packaging whenever possible to reduce our carbon foot print.
10. We use the hardest cutting bit that we can find for less variation.
11. Made by dedicated hard tooling (CNC vs ASPS Machining)
12. Manufacture using lower spindle heights.
13. Manufacture using massive spindle mass for less variation.
14. The scale identification sticker is put on correctly.

Round vs. Square - We were the first to pioneer the use of round notches. When we first started making these we made square notches. We quickly learned it was easier to measure the frets (see diagram#2) and we could produce a more accurate slot with a round hole vs. a square slot. This is because the cutting tool is stronger because it does not have to reach to the very corners that cause less flexing of the tool bit when it cuts. We also use the hardest/strongest cutting tool we can find. And we cut the shanks down as much as possible so we can lower the cutting head as close to the scale as possible to reduce as much flexing as possible. It also requires less energy to manufacture thus reducing our carbon footprint. It takes over one hour to cut our shanks of our cutting bits using a diamond cutter. That's a hard cutting bit!!

Offset Scale - What is "Offset Scale". It's a good question because we had to invent the term to solve a problem that is common with these scales. Here is what happens. Most scales are based on the math of how to machine the scale so all the frets will fit. This would work well if it only had to fit the frets, but it also has to fit the nut. The nut can be hugely larger than the fret and not knowing what size the nut might be this is often overlooked. The result is a scale that will not fit. To solve this problem we "Offset" the scale to accommodate variations in most nut designs. As a result, this greatly improves the compatibility of our scales fitting any particular design of guitar or other instrument.

Higher Grade Aluminum - Most scales and straightedges are manufactured from "Architectural Grade" aluminum. These grades are manufactured mainly for cosmetic appearances and have little strength. We use structural grade aluminum in our scales. You can easily see the difference in that architectural grades look smooth and uniform, and the structural grades have a distinct grain that runs horizontal. Even though the construction grades don't have a nice as appearance we still use them because we feel the strength is much more important for having and maintaining dimensional accuracy.

CNC vs. Laser vs. ASPS Machining - Our scales are manufactured through dedicated hard tooling (ASPS Machining). This has numerous advantages over CNC. CNC can have a position accuracy of .001 or better, but what they do not tell you is how it is setup and the type of CNC used can create a lot of 'chatter' and flexing of the tool bit that can cause the cutting tool to be off as much as .125 of an inch. ASPS uses dedicated hard tooling that reduces the typical spindle height of a CNC machine (1 to 5IN) to .010IN or less for ASPS Machining. This makes our system tremendously more rigid. In addition our machining uses dedicated mechanical interlock system that forces the cutter to cut in the right place. CNC machining is "free floating", if it wanders off because of programming error, flexing, or other problems it can be often hard to catch. Another way to make scales is by laser cutting. We feel lasers are not a good system as the heat build up can cause the notches to be placed in the wrong location because of the thermal expansion of the aluminum (see Temperature Declaration). ASPS machining solves all these problems.

Temperature Declaration - Aluminum can expand and shrink more than you might expect. Its best to use a scale at the same temperature that it was manufactured at. If a scale is machined in a foreign country at 120 degrees Fahrenheit (not uncommon for a manufacturing environment) combined with cnc machining process can push the temperature of the aluminum to 500 degrees or more. And if you used that scale on a cold winter day in your unheated shop it could be off by as much as 1/8 of an inch! That's why we declare the temperature of which our scales are manufactured at: between 65 and 85 degrees. If the temperature of our metal exceeds this range we stop the process to investigate what is wrong or let the metal cool before continuing. This reduces the thermal variation over the total length to a theoretical maximum of .004in. Typical variations can be found in the .002in range or less.

Recycled Packaging and Carbon Footprint - It ships in reinforced recycled packaging and we use green energies whenever possible in the manufacturing of this product. We also use bicycles to make our post office shipments whenever possible to reduce our carbon footprint.

Note: Fret placement on musical instruments are often done by hand and misalignment of the frets as measured by the scale is only an indicator and may not mean a defect in the quality or workmanship of the instrument(s) being checked.

Related Products

1. Straight Edge for Luthiers Tool, Guitar Neck, Instruments, Bass, Un-notched (48in)
2. Straight Edge for Luthiers Tool, Guitar Neck, Instruments, Bass, Un-notched (24in)
3. Straight Edge (Aluminum Flat Bar Stock 1.5 in x 18 in, 1/8 thick, 1.5in, 1.5 in, New)
4. Rocker Leveling Tool for Frets -Luthiers Tool, Guitar, Mandolin, Banjo, Bass,FS!

Questions and Product Support

Q. One of my frets does not fit my scale, can I file it so it will fit?

A. We get reports from time to time of frets not fitting into a particular notch of the scale. Usually it is with frets 21 to 23, or with the nut (fret 0). You can use a 1/8in round file(Chainsaw file) to enlarge the round holes in the needed direction. If its with the nut, people will sometimes use a flat file and file a little triangle opening to make room.

Q. I noticed some metal flakes on my scale when I received it.

A. Some times some metal flakes get stuck on the scale from the machining process. We found that then can easily be removed and cleaned up by using an old toothbrush. There may also be light traces of oil on the edge which can be removed by simply pressing against a paper towel.

Materials Used

Aluminum T6511

Product Attributes

Color: Grey

Accepted Payments
  • PayPal Acceptance Mark


United States
First Item: $3.25
Additional Items: $3.25

All Other Countries
First Item: $9.99
Additional Items: $4.50





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Poolngolf on Dec 6, 2016
5 stars

Thank You! The packaging could have been a bit better, it was evidently dropped and it dented the edge on one end. I should be able to sand it back smooth. Other than that I think it will work nicely!

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