Installing Tuning Machines

Shrunken celluloid
tuning machine button

Tuning machine replacement s necessary when desiring a better quality tuner or to replace a damaged one. With the exception of some bass tuners they are normally sold as sets, not individual tuners,

Worn out tuners often have excessive play between the round and worm gear resulting in skipping or play in the tuning machine arm (movement with response from the tuning machine post).

Generally speaking, if you can find retrofitting replacements for your instrument this is normally a simple procedure. When the machine head bushing has a nut and washer then it must be removed before the tuners will come out, other simply have press fit bushings when do not need to be replaced if the same design is being used.

Selecting New Tuners

When choosing a replacement tuner that is not identical to that which you are replacing it is important to note measurements of:

measuring tuners post heightTuning post height can vary. It is important to insure the string hole will still be accessible once the tuner and it's bushing are installed on the peghead. Be sure to check the specifications before drilling any new holes.

Fitting New Tuners

If you are replacing your old tuners with identical tuners then you need little more than a screwdriver and nut driver, however, if the original style is not available or not desired some upgrades may require modifications.

Such modifications may include:

Care should be taken to avoid chipping the finish or peghead veneer when removing pressed in machine head ferrules. When dealing with vintage instruments it is highly advisable to seek a retrofitting replacement so that no changes are made if possible.

Gear Ratios ........15:1 18:1 20:1

The gear ratio indicates how many times the tuner button is rotated 360° to one turn of the tuners post. A higher ratio permits finer adjustments, reducing the aggravation of tuning up and down repeatedly before perfect tuning is achieved.

Removing Tuning Machine Bushings

Tuning machine bushings, also called ferrules, are inserted into the front side of the peghead and act as a collar for the post. Some bushings screw to the tuner, others are pressed into the peghead and held in place by friction.

When removing a press fit bushing care must be taken to avoid chipping the peghead or finish. Some of these bushings are extremely tight. Others have been glued in place in an attempt to keep them from falling out...not recommended procedure.

The safest method I have found to remove them is to press them out. Using a simple wood block which I have drilled to match the diameter of the bushing, it is placed over the ferrule and a dowel is used to press it up and out. Sometimes you can do it by hand, on very tight bushings, I must use a clamp.

My instrument won't stay in tune, are the tuners at fault? In general, worn out tuners make an instrument hard to tune. Loss of tuning has many causes. Read more here.

Loose Bushings

The ferrules (bushings) that press into the fingerboard don't always fit snuggly. If one isn't careful it is quite easy to loose these when the strings are removed.

To tighten bushings that are only slightly loose without permanently gluing them into the peghead hole I shrink the diameter of the hole.

If the gap is minor and does not warrant filling and re-drilling then I use superglue to build up the walls of the hole until it becomes smaller in diameter. Again, we do not want to glue the ferrule to the peghead as damage can result when it must be removed. The superglue is applied and completely dry before bushings are re-installed.

Tuners: The Basics

Gear Ratio

A tuning machine's Gear Ratio (ex. 15:1) tells us how many times the tuner's knob must be turned before the string post rotates a full 360°'s.

The higher the gear ratio the more precise the tuning is as relatively small adjustments can be made.

Bushings

(Press On vs. Bolt On)

The tuning machine's bushing (also called ferrule) is inserted into the peghead and surrounds the tuner's string post.

Some bushings are simply pressed into the peghead hole and remain there by friction. Others, screw to the tuners. In most cases the required peghead hole size will differ.

Locking Tuner

Locking tuners clamp down on the string as it passes thru the tuning machine post hole. Most use a "vice" like mechanism which is tightened/loosened by a knob on the back side of the tuner.

Mini Tuners

Some smaller pegheads use mini tuners to allow closer side by side mounting and reduce weight.

Graduated Tuners

Graduated tuners have lower posts for strings that are further away from the nut (treble B and E string). This is helpful for pegheads that are not angled. An example of a non-angled peghead would be a Telecaster, an angled would be a Les Paul.

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