Loose Tuning Machine Bushings

How do I keep the small bushing (ferrule) that fits around the tuner's post from falling off?

You may have already noticed that some tuning machine bushings screw to the tuner while others simply press into the holes in the peghead. Well, they're suppose to anyway. Unfortunately loose press fit tuning machine bushings can fall off easily when the strings are removed. With any luck it will hit the floor and roll, usually right to the spot you look for it last!

For screw on bushings we merely tighten them with a nut driver (10mm is a very common size), but for press fit bushings we must address the size of the hole in the peghead.

Comparison of Tuners Using Screw On & Press Fit Tuning Machine Bushings

Common Problems:

• The hole was drilled too large for the bushing to fit securely
• When replacing the tuning machines the replacements are slightly smaller than the original
• Humidity levels have changed and the ferrules have become loose

Martin guitar with Butterbean tuners and loose bushings.

Don't Glue The Bushing To The Peghead

My technique for securing the loose bushing to the peghead does not include gluing it in hole. Why not? First and foremost I simply don't want to alter the instrument. An unsuspecting repair person may wish to remove the bushings in the future, not expecting them to be glued in, and do serious damage to the peghead if precautions are not used.

For Slightly Loose Bushings

When a bushing is only a little loose, layering the sides of the hole with superglue can decrease the size of the hole just enough to allow the press in bushings to fit securely. I call this "padding". 

I apply Hot Stuff Super T medium viscosity superglue in very thin coats until it's thickness has decreased the size of the hole. Because the glue changes the size of the hole, it is not unusual to go from having a hole that is too large to one that is a little too small. If this happens I use a peghead reamer to size the hole just as I would on new construction.

Caution!

While this is a simple repair it is easy to make a mistake that can turn this into a major headache.

Superglue drips easily! A drop of superglue on the finish can turn an otherwise quick and easy repair into a time consuming finish repair. 

Using too much glue or very thin glue may cause it to run down the sides of the hole and pool along the backside of the peghead.

Installing the ferrules before the glue has dried completely could cause the bushing to stick when attempting to test fit.
Obviously, you may wish to have the repair done for you if you are uncomfortable with the idea of practicing this on a valuable instrument.

Glue "pads" the sides of the hole to slightly decrease it's size. Allow it to
cure before installation of the bushings.

For Very Loose Bushings

While that technique is ideal for machine head bushings that are a little loose, those that fit so poorly that they move side to side require more effort. This is usually only a problem if one is installing replacements that are not replica's of the original or when the guitar has had multiple sets installed thru the years which have damaged the peghead hole. In these instances plugging the holes and re-drilling is usually necessary.

This vintage Gretsch Synchromatic guitar has been thru several tuner replacements
leaving the peghead holes oversized and peppered with screw holes.

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