Surface flatness is something of a science. There are actually gauges made to measure this, and they come in various types and with different levels of accuracy and expense.
When we left off last time, we had finished leveling and crowning the frets. At this point, the tops of the frets would all be level with each other, and the tops would also be rounded (crowned). However, you''ll recall that the initial leveling left the frets with scratches in their tops, and this would make the guitar uncomfortable to play, especially if you bend the strings. The guitar would feel "scratchy." So at this point, we need to get the scratches out, and this step is typically called polishing.
Here''s how abrasives work: as you sand something, the abrasive particles scratch the surface you''re sanding. The sanding may make the surface "flat" (a relative term, as we shall see), but it also scratches it. If you sanded with 120 grit sandpaper, you would have relatively large scratches, and if you looked at a photomicrograph of the surface, you would see that it didn''t look flat at all. The scratches would look like huge valleys.
You would then follow up with the next grit, like maybe 220, and this would also scratch the surface, but because the abrasive particles are smaller, the scratches would be smaller than the 120 grit scratches.
The idea with sanding is to obliterate the larger scratches from the previous grit with smaller scratches from the current grit. As you move up through the grits, each time completely obliterating the larger scratches from the previous grit, the scratches will get smaller and smaller with each successive grit until you can no longer see them with the naked eye.
Surface flatness is something of a science. There are actually gauges made to measure this, and they come in various types and with different levels of accuracy and expense. There are machines that will measure surface roughness in millionths of inches, so you can see that "flat" is indeed a relative term.
One simple type of surface roughness gauge is a cylinder with graduations on the side. You set it on the workpiece, and then look at its reflection in the workpiece. The flatter the workpiece, the less distortion in the reflection, and the more of the graduations you can read. The highest graduation that is readable indicates the degree of flatness. If you want to see something really flat, open an old computer hard drive (you know, one of those old 20Gb drives) and look at the platter(s). Now that is flat.
To get the frets really shiny (meaning that the scratches are really tiny), the final steps may be done with buffing compounds. Some repair people finish with 0000 steel wool, which is pretty fine, but won''t leave a finish as shiny as buffing will.
You''ll recall that at Acme, we use a surface-ground bar to level frets. One edge is coated with industrial diamond (which is fairly coarse: 220-320), and the other side has no coating. After crowning, we use various grits of sandpaper adhered to this uncoated edge (using the bar in the same way it was initially used for leveling), and finish with 600 grit paper. The final step is to mark the tops of the frets one last time, with the neck still held in the jig to prevent deflection, and use the 600 grit paper to remove the marker from the tops. This leaves the tops with very small scratches, while ensuring that everything is still level.
The final step is to buff the frets. A buffer is just a felt or muslin wheel that is "loaded" with very fine abrasive. This abrasive usually comes in a stick form (in various grits, all of which are very fine), and the stick is pressed against the rotating wheel to load it with abrasive. The guitar neck is then passed across the face of the wheel, back and forth, until the scratches from the 600 grit paper are obliterated. Acme has two buffers, each with a coarse and a fine set of buffs. One buffer is dedicated to polishing metal and the other buffer is set up for finishes (like lacquer).
The frets are first buffed using the coarse abrasive, which obliterates the 600 grit scratches, and then the fine abrasive obliterates the scratches from the coarse abrasive. And at that point, the frets look like little pieces of sterling silver jewelry. They look bee-yoo-tiful!
And the final steps are cleanup, restringing, and setup. Next month we''ll discuss setups.
Acme Guitar Works sells electronic components for electric guitars, including complete, prewired assemblies. Visit them at acmeguitarworks.com.
Looking for more great gear for the guitar player in your life (yourself included!)? Check out this year's Holiday Gear Finds!
D'Addario XPND Pedalboard
DR-05X Stereo Handheld Recorder
Wampler Pedals Ratsbane
Outlaw Effects introduces their next generation of NOMAD rechargeable battery-powered pedal boards.
Available in two sizes, NOMAD ISO is a compact, versatile tool that offers the convenience of a fully powered board plus the additional freedom of not having to plug into an outlet. NOMAD ISO is ideal for stages with limited outlet availability, quick changeovers, busking outdoors, temporary rehearsal locations, and more!
NOMAD ISO builds upon the legacy of the ultra-convenient and reliable NOMAD rechargeable pedalboard line originally launched in 2018. The brand new NOMAD ISO editions feature eight isolated outputs (1 x 9V DC, and 1 switchable 9V/12V DC) for even more versatility and clean, quiet power. With an integrated lithium-ion battery pack boasting 12800mAh capacity, NOMAD ISO can fuel a wide array of pedals, and will last over 10 hours* on a single charge.
Each NOMAD ISO pedal board includes adhesive hook & loop pedal-mounting tape, eight (8) standard DC connector cables, and one (1) reverse polarity DC cable, giving you everything you need to build your ultimate "off-the-grid" rig. A rugged, road-ready padded gig bag with shoulder strap is also included, to safely protect your gear while you're on the move.
NOMAD ISO S: MSRP $309 / MAP: $249
Dimensions: 19 ¼" x 5 ¼"
NOMAD ISO M: MSRP $349 / MAP $279
Dimensions: 19 ¼" x 11"
More info: https://www.outlawguitareffects.com.
Dunable announce new Minotaur model featuring Grover Rotomatic Keystone tuners.
The Minotaur's DNA is rooted in their classic Moonflower model, which Dunable discontinued in 2017. However, they have long since wanted to create a fresh take on a carved top guitar design, and various attempts to rework the Moonflower led them to a brand new concept with the Minotuar.
Dunable's goal is to give the player a guitar that plays fast and smooth, sounds amazing, and gives maximum physical ergonomic comfort. The Minotaur's soft and meticulous contours, simple and effective control layout, and 25.5" scale length are designed to easily meet this criteria.
- 25.5" scale length
- Dual Humbucker
- one volume, one tone, push pull for coil splitting
- Grover Rotomatic Keystone tuners
- Grover Tune O Matic bridge with brass Kluson top-mount tailpiece
- jumbo nickel frets
- 12" fretboard radius
This full-amp-stack-in-a-box pedal brings a new flavor to the Guitar Legend Tone Series of pedals, Missing Link Audio’s flagship product line.
Adding to the company’s line of premium-quality effects pedals, Missing Link Audio has unleashed the new AC/Overdrive pedal. This full-amp-stack-in-a-box pedal – the only Angus & Malcom all-in-one stompbox on the market – brings a new flavor to the Guitar Legend Tone Series of pedals, Missing Link Audio’s flagship product line.
The AC/OD layout has three knobs to control Volume, Gain and Tone. That user-friendly format is perfect for quickly getting your ideal tone, and it also offers a ton of versatility. MLA’s new AC/OD absolutely nails the Angus tone from the days of “High Voltage” to "Back in Black”. You can also easily dial inMalcom with the turn of a knob. The pedal covers a broad range of sonic terrain, from boost to hot overdrive to complete tube-like saturation. The pedal is designed to leave on all the time and is very touch responsive. You can get everything from fat rhythm tones to a perfect lead tone just by using your guitar’s volume knob and your right-hand attack.
- Three knobs to control Volume, Gain and Tone
- Die-cast aluminum cases for gig-worthy durability
- Limited lifetime warranty
- True bypass on/off switch
- 9-volt DC input
- Made in the USA