Schertler Open-back Tuners
Known by several names (machine heads, tuning machines, tuning pegs, tuners), and available in a plethora of configurations and performance characteristics, tuning machine heads (or tuners) are a critical component of a functioning acoustic guitar. Aesthetically, they range from utilitarian to museum-quality works of art.
This article is intended to explore the form and function of some of my favorite knobby, gear-driven thingies, those simple but fascinating little machines that I rely on to tighten, loosen and maintain the pitch of the strings on my guitar.
Schertler Open-back Tuners
Two thousand years ago, stringed instruments such as the lute, barbat, pandore, oud, zither, cittern, etc. all relied on tuning pins or pegs to hold strings under tension by friction. Tuning pins, such as are still found on harps and pianos, utilize a removable key or wrench to adjust. Tuning pegs (friction pegs, pegs) are essentially conical dowels that wedge into tapered holes. Though typically turned from wood, these pegs may also be made of other materials including bone, brass, etc. A thumb knob is integral to the design, qualifying each peg as an independent string tuner. Such tuning pegs made their way onto ukuleles and early guitars and remain a preferred component of orchestral stringed, bowed instruments such as violins, violas, cellos; even the upright bass.
The invention of the modern tuning machine head (aka machine head, tuning machine, tuning head, tuner, etc.) is credited to Viennese-born Johann Georg Stauffer, an Austrian luthier who presented the world with the first worm-gear driven tuner in 1825.
Incidentally, German-born Christian Frederick Martin moved to Vienna at the young age of 15 where he apprenticed with Stauffer, remaining in Vienna for 16 years. Martin later moved to the United States where he founded C. F. Martin & Company.
1840s Martin with Stauffer Tuners
Unlike both the independent tuning pegs of old and the now ubiquitous independent tuning machine heads, early metal tuners all shared a common mounting plate. This “on-a-plate” design eventually became associated with slotted headstocks and Nylon String / Classical guitars, though they started out on solid headstocks. Martin continued the Stauffer tradition of the scroll-shaped solid headstock for several years, but began producing slotted headstock instruments that featured plate tuners from the likes of Jerome, Seidel and Waverly.
Kluson Plate Tuners
One hundred years after Stauffer introduced his open-back metal tuners, John Kluson of Chicago started up his shop where he was enclosing worm gear tuners inside metal housings. Though not perfectly sealed, these enclosed tuners addressed the issue of early tuner gear failure due to dirt and debris.
Stauffer invented his tuners just 2 years before Albert Grover of Boston, Massachusetts was born. Grover grew to be a prolific inventor and held many patents, not the least being the development of independent (as in, not on-a-plate) tuning machines. The company Albert began with his son, aptly named A. D. Grover & Son, was purchased by Grossman Brothers Music Company in 1952 and the new company, Grover Musical Instruments, developed the fully enclosed Grover Rotomatic Machine Head which quickly became an industry standard.
Grover Rotomatic
Cleveland, Ohio native Robert J. (Bob) Spercel was born in 1916 1923 (corrected - many thanks to Bob's daughter, Cheryl). Bob learned tool-making and machining skills from his uncle and, among many other accomplishments, introduced his own solution to the guitar world: the Sperzel Trim-Lok Tuner, which Fender Guitars aptly named the "World's Finest Guitar Tuner" in the May 1979 issue of Guitar Player Magazine.
Sperzel Trim-Lok
Manufacturing tuners since 1977, it was in 1983 that Sperzel introduced their revolutionary Trim-Lok design. These innovative tuners made it possible to simply pass the string through the hole in the post, pull it taut, tighten the knob and clip off the excess. Strings now stayed in tune, as the multiple post wraps of yesteryear, which continued to slip as you played, were no longer. String changing times dropped dramatically. And everybody sought to copy the design.
Four men, namely; Stauffer, Kluson, Grover and Spercel, from three cities, Vienna, Chicago and Cleveland, made these significant contributions to the guitar world over a period of approximately 150 years.
I have used many brands of tuners in my own guitars throughout the years, including Kluson, Grover, Schaller, Waverly, Steinberger, Graph Tech (Ratio), Gotoh, and others. But the tuner I have grown to admire most is the innovative, lightweight and customizable Sperzel Open-Back Trim-Lok tuner.
Sperzel Open-Back Trim-Lok
In addition to being machined from aluminum, and thus being significantly lighter in weight than its contemporaries, the re-engineering of the design of the Sperzel Trim-Lok eliminated the post/shaft wobble common in most all the other tuners on the market. Backlash was reduced to near non-existent, eliminating the need to first under-tune and then creep up to pitch for each adjustment to each and every string. As I mentioned above, the Trim-Lok feature eliminated wrapping the string around the post which, along with poorly-seated ball ends, accounts for the seemingly endless re-tuning of new acoustic guitar strings, as the strings are constantly loosing tension as they either slip up past the bridgeplate or wrap tighter and tighter around the post.
Performers: take note!
With the Trim-Lok one merely pulls the string taut through a small hole in the end of the post, followed by tightening the knob on the back of the headstock. Tuning the string to pitch requires anywhere from 1/4 to 3/4 of a turn around the post. This feature, in addition to providing player confidence, makes long and tedious string changes a thing of the past!
I own several Guild acoustic 12 string guitars, the oldest having been built in 1975. Two (2) of my guitars came with paired steel open back, 6-on-a-plate tuners from the factory. All the rest had extremely heavy Grover sealed gear housings. I do not believe in leaving things that work perfectly fine alone, at least not for any length of time, and am constantly exploring and experimenting.
Tuners are no exception, and I have swapped them all out over the years. As you may be aware or can imagine, open back plate tuners are much lighter in weight than sealed machine heads. But they are made of steel and are not lightweight, overall. Older Guild 12 strings are already notorious for their heft (having twin steel compression rods in the neck), and adding extra ounces of metal on the headstock in the form of sealed gear tuners certainly does nothing to help. Here is a 12 string fitted with the lightweight Sperzel Open-Back Trim-Lok tuners. What a difference!
1976 Guild F-512 with Sperzel Open-Back Trim-Lok tuners
You can read more about these tuners on the Sperzel website » Sperzel Guitar Tuning Machines
Update: In December 2024, Matt McCracken of Guitar World Magazine rated a Sperzel Locking Tuner as the "Best Overall". Go Matt! He also asked and answered a great question. With his permission, let me quote him:
Q. Can you put locking tuners on an acoustic guitar?
A. Yes you can put locking tuners on an acoustic. They’re a great upgrade for any acoustic guitar and we’re not really sure why more manufacturers don’t fit them as standard . . .
You can read the full article, here » Best locking tuners 2024
The tapered friction pin tuning pegs found on both the earliest of stringed instruments, as well on most bowed instruments made today, features a post, or shaft that is supported in two places (it passes through two holes). A roller-style tuner, as is found on most all nylon-string guitars, also requires support in two places. The headstock must be slotted to support this design.
A benefit of the slotted headstock, roller-style tuner configuration is ergonomic; it is very comfortable to reach up from behind the headstock, pinch a knob and turn it to make adjustments to the pitch of the string.
Alessi Roller-style Tuners
The post-style tuners, as found on solid headstock electric and acoustic guitars, expose a free-standing shaft, or pole on which to wrap the string.
When contrasted with a roller-style tuner, the contorted effort required to make an adjustment to a post-style tuning machine is a bit humorous to view. If you, the player/performer, have ever experienced arm joint pain (shoulder or elbow) for whatever reason, the perfectly un-ergonomic posture of a post-style tuner is not so funny.
Nevertheless, post-style tuners are the norm for most all electric and acoustic steel-string guitars.
Alessi Post-style Tuners
A worm gear transfers the twisting motion of the knob to the rotating of the shaft, or post of the tuner. In the lightest-weight offering, the gears are exposed, and can accumulate dust, lint, fur, hair, leaves, peanut butter and most anything else you choose to store in them.
Gotoh Open-back Tuners
As I mentioned earlier, Kluson is credited with being the first to enclose the open gear in an attempt to protect it from dirt, dust and debris. It was a welcome introduction and quickly caught on. Grover took it a step further by actually sealing the gear inside a housing with permanent lubrication. This design quickly became the standard on solid headstock guitars, both electric and acoustic, and endured for the better part of 1/2 a century.
But practicality comes at a price and, in the case of the sealed, or closed-back tuner, that price is felt both in weight and visual appeal. Builders and players alike began experimenting with open-back designs again, and a resurgence of the exposed gear tuning machine has supplied us with more options today than we can possibly enjoy in a lifetime.
Gotoh Closed-back Tuners
I was slow to adopt the locking tuner, and the only explanation I can come up with is ignorance. I didn't know they existed when I was younger, and I was too busy to care as I grew older. One day, post the invention of the Internet, I stumbled quite by accident onto the topic and ordered a set to try out for myself. The rest, as they say, is history.
Traditionally, a steel string is left a bit longer than the distance from the saddle to its corresponding tuner post, set into a hole in that post and wound several times to secure it in place via friction. Additionally, a couple of techniques may be employed that interlock the windings. There will be some slack in those windings, regardless of one's restringing technique. That slack is especially noticeable upon installation of new strings, and contributes to the seemingly incessant re-tunings required until all the slack is taken up. For some of us who love the bright response of new strings, by the time that occurs we are just about ready for new strings. C'est la vie!
Locking tuners eliminate the slack by pinning the string in place. No windings are needed to secure it. One-quarter to one-half rotation of the post are usually all that is required to bring the string to pitch. And it stays there!
What are the differences between locking and non-locking tuners?
How A Locking Tuner Works - courtesy Haze Guitars
12: 1 ("twelve to one"), 15:1, 18:1, 21:1 - So what is all the fuss about?
Assuming the various components of your favorite tuners have been manufactured having close tolerances such that they operate smoothly (gears mesh, posts rotate and knobs turn all without binding), do you need to even bother with gear ratio (a number that determines how many full rotations of the knob it takes to rotate the shaft 360°)?
If you are thrilled with what you have and don't want to spend any more money on your guitar, then the answer is NO.
For the rest of us, the answer is yes, Yes, YES!
Higher ratio numbers equate to more teeth on the worm gears which, in turn, translate to greater precision when dialing in the right pitch.
Mostly.
Until you realize that A.) Small diameter (gauge) strings seemingly take forever to initially tune during string changes than they would if you had a lower number ratio, and B.) On a steel string guitar your string gauges vary wildly, creating a vastly different tuning experience string-to-string. That old, tried-and-true 12:1 ratio wasn't arrived at by accident; it provides for a pretty decent "happy medium" for most 6-string guitars.
But must we settle for a happy medium?
From GraphTech, the Canadian folks that brought us TUSQ, comes the appropriately named Ratio machine heads. By supplying an optimized gear for each string, ranging from 12:1 to 39:1 (up to 48:1 if you play a 7-string), you get a unified tuning experience. It is delightful!
Graph Tech offers both open and closed back versions, along with locking and non-locking models in several colors and with several button styles. Ya gotta try these.
Graph Tech Ratio Machine Heads
The banjo tuner (or Peg) is an interesting study. Today's mechanical device has stayed most visually true to it's origins as a vertical friction peg that is accessed from the back of the headstock with a thumb knob. By incorporating a so-called planetary gear system, the modern banjo tuner offers high torque and no backlash in the most compact design.
Planetary Gear Simulation
While all the major machine head manufacturers offer a 4:1 tuner, expected on banjos, Steinberger shook up the guitar world with their innovative "gearless" and "locking" tuner, featuring an unrivaled 40:1 ratio for precision tuning.
Steinberger Gearless Tuners
My first instrument as a boy was an early 1960s Stella 4-string "tenor" guitar that featured open-back "post" style tuners. I broke many a string on that guitar, which was not a pleasant experience, as there was usually a very long wait time for a replacement string. But my Stella and I were fast friends!
Stella - My First Guitar
When I was 11 years old, and it was firmly established that I was not going to stop playing the guitar, my parents found me a teacher. They purchased a nylon string string guitar for me, a 1970 Lyle Classical guitar, and I began a more serious journey. Re-stringing and tuning that nylon string guitar was a completely different experience for me. An open gear design, this was my first guitar that featured "roller" style tuners mounted on a slotted headstock.
1970 Lyle Classical Guitar
After three years of classical guitar instruction I was ready to start strumming again with my friends, none of whom played guitar using their fingers.
I got a 1973 Epiphone jumbo guitar and a whole new world opened up to me. The 17" body was a monster for me as an early teenager, and the fully sealed chrome tuners were HEAVY! But that Maple and Spruce guitar really started me on a path I have continued to walk to this day.
1973 Epiphone FT-570 BL "Sheraton"
When I was 16 years old, I obtained a loan from my local Credit Union and purchased a brand new 1976 Guild F-50 R NT, a Rosewood and Spruce jumbo featuring Grover Rotomatic sealed tuners. It would be several decades before I learned how to reproduce that Guild jumbo sound that I grew to know and love.
And as for the tuners? I put Grover Rotomatics on nearly every I guitar I made or purchased for the next 30 years. And I still use them on occasion, especially if that what a customer wants.
1976 Guild F-50R NT "Navarre" (circa 1980)
Having experimented with so many tuning machine heads over a lifetime, I truly appreciate most all of them, for one reason or another. I used to have a bench drawer full of various manufacturer's offerings. I now have a cabinet full! But I keep returning to the Sperzel Open Back Trim Lok, as it combines so much of what I like into one very attractive, lightweight tuner.