Repairing Broken Kluson Tuning Machines

Today we are fixing one of the most common breaks on a set of 3-on-a-plate Kluson "single line" tuners. The D tuner shaft sustained an impact and the cast brass had sheared. These tuners were designed to remain sealed and so opening them seems daunting but they are quite simple in design 

You can seriously disfigure and even ruin your tuners if done improperly and patience is key to success. If you're unsure, STOP, install a set of replacement Klusons, and keep the originals in the case for a proper repair

This is the wrong (but far too common) approach.
If the tuners were simply removed and replaced then these could've been repaired

Shame because these were a rare set of Safe-Ti-String posts with butterfly buttons

What You'll Need

• At least one donor Kluson tuning machine from the same era (I have yet to see if the reissues will work)
• Ball peen or similar small hammer
• Junky wood chisel
• Nail punch (a few different sizes wouldn't hurt)
• Padded bench vise
• Needle-nose pliers
• Soldering Iron
• Thin CA glue with a whip tip

The Process

Using a cheap chrome vanadium chisel, I bend the forward tab upwards where I can use a nail punch and ball peen hammer to carefully bend the tab to a vertical position. Use light taps and try not to lever off the plate! If you stress the tab too much it will snap off and then you're in trouble 

Then tap the tab through the plate and you should be able to carefully bend the casing backwards enough to remove the broken worm gear. 

 Have you ever broken off the tab on a soda can by rocking it back and forth? You don't want that to happen so the fewer times you bend the back tab, the better

Here is the broken brass worm gear and shaft with the replacement I pulled from a 'donor' set of broken Klusons. It doesn't matter if your part comes from the treble or bass side, they will work all the same. I'll use alcohol to clean off the old grease and crud

Seat the replacement worm in the tuner casing and make sure it fits

Now you will gently bend the casing back into place, you may need to bend the front tab so that it is aligned with the hole in the plate.

The plate has become slightly bent, this isn't difficult to fix but I would recommend waiting until the end

Using my padded vise, I compressed on the tuners which seated the casing back into the plate and locked the worm gear in place

Using a nail punch and taking gentle hits, I bend the tabs back into place. If your punch slips you'll scratch the back of the plate which isn't the end of the world but looks cleaner if you avoid it

I'm no machinist so I don't really have a go-to lubricant for these parts (friendly reminder WD-40 is not a good choice) but I use 3-in-one PTFE and it has worked out well for me

Put the broken shaft into your padded vise with gentle pressure and use a soldering iron to apply heat. If you get the shaft too hot, you will melt and distort the button. I typically apply heat for 10-15 seconds, pull on the shaft with needle nose pliers, rinse and repeat until it's free. 

Now the button is free from the broken shaft and we can see two bends which would be consistent with a collision. The tuner button got slightly hotter than desired and the button has formed a small collar of melted material around the hole. I'll use a sharp razor blade to trim it back.

Note that the shaft has a "spear" shape with a "wing" on either side, this cuts into the button and prevents them from spinning freely on the shaft. 

Using your soldering iron again, heat up the worm shaft on your tuners (until the string post is warm) then press the plastic button down on it. Then, acting quickly while everything is warm, put the tuners into a padded vise and push them together. The existing tuner buttons will act as a depth stop so you don't push the button too far.

Important things to note

• Ensure that the "wings" on the shaft and the button are lined up, we don't need to put any more tension on this old plastic than necessary
• If the shaft is too cold then you'll see the button distend or see stress cracks forming
• If the shaft is too hot then you will see it melt and also distend 
• If your button goes on crooked, heat up the shaft again and you should be able to shift it by hand or by holding it a vise.

I flood the inside of the button with thin CA which reinforces the bond between the melted plastic and the brass and fills any gaps

And here is the finished product! The patina on the replacement brass shaft (top left) doesn't match the existing ones but they are functionally identical and I'd call that a rescued set of tuners!

I don't believe the tuner shafts could be brazed back together and remain strong but I hold onto the old parts anyways. Perhaps replicas could be cast 

Finally, if the plate had become bent from the earlier steps, simply place it in a padded vise and apply light pressure with your hand to coax it back into place. The metal is thin and pliable, so it is not hard to correct

Kay truss rods are not an exceptionally great design, they use the basic compression rod system that Gibson patented in the 1920s but Kay fell short in their execution. 

Gibson used a concave channel for the rod to follow in order for the compression to effectively counteract the forward bow in a guitar's neck. Kay used a nearly flat channel which makes the compression rod have a minor effect but its not always consistent down the neck. Often a Kay truss rod will bow the neck around the 3rd or 5th fret and leave the rest of it untouched. I opt to replace these rods with modern steel truss rods from LMII which perform miles above the original rods and are stronger.

The rod is a long carriage bolt that extends from the nut to just before the neck meets the body. It is held in place by two semi-circle washers with square holes cut in them. The adjustment nut is brass and sized for a 5/16" socket. It bears against a washer and the first semi-circle washer. Tightening the nut pulls the end of the rod towards the nut which bows it and is the basis of the functionality.

The washer at the nut is not attached to the rod but the washer at the far end is held in place by the resistance of the carriage bolt's square-neck against the square channel in the washer. This keeps the rod from turning freely when you try to tighten the adjustment nut.

My Kay truss rod turns freely, how do I fix this?

Using a pair of needle nose pliers, grab the brass adjustment nut (while it is attached to the rod) and give it a gentle wiggle. You should be able to push and pull the rod and have it move about an 1/8" overall. Pull the rod and give it a gentle twist to see if it moves. If the rod turns then the square neck of the bolt has not met the washer and I would recommend repeating the process. If the rod does not turn then you should be able to tighten the adjustment nut and your truss rod will work again.

The worst case scenario is that your rod is actually broken in which case you won't be able to fix it and it will need replacing. The best case scenario is that you prolong the life of this (admittedly poor) OEM truss rod and the minimal adjustment it provides.

First I started with a blank of Indian Rosewood which had came from a beam that I bought, ripped into bridge blanks, and waxed the ends to prevent splitting. I took the original, fragile, ebonized wood bridge and traced an outline onto the block with a pencil. Then I used a knife to score along the lines to help make them more visible. 

I took the bridge to my bandsaw to rough cut along the marked lines and start on removing the material for the gap underneath the bridge. I also cut and sanded the bridge to the desired thickness of just a hair under 1/4". At this point I also marked the points on the bottom of the bridge where my screw posts are to be located. Then I placed the bridge upside down on my drill press and drilled both holes through the bridge stopping just short of going through the bridge as I don't want them to be visible through the top

Then I began to round off some of the corners, remove most of the wood for the bottom gap, and start to shape the bottom of the bridge to the top of my guitar. I shape the bridge to the guitar by placing a sheet of 80 or 120 grit sandpaper on the top, holding it in place, and running the bridge back and forth across it lengthwise. That removes just the right amount of material so the bridge fits perfectly on the top which helps transfer energy and resists side to side moving. I also run the bridge on my belt sander to start tapering the long edges towards the top like an isosceles trapezoid. 

Then I separated the pieces of the bridge by running it through my bandsaw. Notice the screw holes are perfectly aligned because I drilled before cutting the bridge. I've also begun to rough out the compensation for the strings and tapering the bridge even stronger towards the top to form a point

I've oiled the wood and begun to polish it to a shine starting with 220 grit and ending with 3000 grit dry sandpaper. While still in the rough grits, I lightly dampen the wood with water to raise the grain and sand it off to help achieve a super smooth finish. Then I begin adding oil by rubbing it on then off while continuing to sand. Rosewood takes oil very well and can be polished to a point where it looks shiny.

I use Dr Ducks Axe Wax for this purpose and general maintenance of my guitar fretboards

Here is the bridge sat atop my Harmony Rocket. I used the thumb wheels from the old bridge and some screw posts that I had lying around. Harmony anchored their posts into the top half of the bridge which I don't much like so I reversed it and anchored my posts into the base of the bridge, as is more common. This Indian Rosewood is pretty dark so I think it will match the Brazilian Rosewood fretboard quite well while also being a large structural improvement over the brittle, ebonized bridge.

Image Credit: Reverb - Hippie Holidaze

Pinless guitar bridges are the designed so that the strings loop through the bridge and then over the saddle eliminating the need for plastic pins and holes drilled into the guitar top. Kay started using them more in the early 1960s on their flat top guitars.

This design has the strings come in through the front of the bridge (saddle-side) and out through the back where they wrap over the bridge and onto the saddle. I consider these bridges to be less stable for the high tension of steel-stringed instruments and with subpar sound. The strings are held in place solely by the bridge and so the pulling tension is counteracted only by the strength of the rosewood bridge and the top is merely glued to this bridge. The top doesn't contact the strings nor offer any direct support but instead holds the bridge which is trying to be pulled away from it.

I set out to convert this bridge to a pinned one.

 My first step was to cut some Indian Rosewood to fit in the rectangular channel cut into the bridge. I rounded the corners to match the corners of the bridge and got a snug fit after trial and error. I used a plastic circle tracing sheet to get a good radius and then sanded to it using my belt sander. I glued the piece into the bridge using thick Cyanoacrylate, because this patch is permanent, and filled any small gaps with thin CA and rosewood dust which form a surface that is very similar to real wood after sanding.

 The other side of the bridge includes a similar rounded, rectangular channel cut into the side with 6 string holes drilled through it. I filled the holes with maple dowels (thin Rosewood dowels aren't something you can easily find and this is structural, nobody will see it) and cut another piece of Indian Rosewood to fit in that channel and filled using the same methods as above.

 Then I took the bridge to my belt sander to sand the grafted wood flush with the bridge. I had to be careful to not hit the base of the bridge and change the footprint because that would be very difficult to hide on the top of the guitar. This picture was taken after I sanded the patch and oiled the wood.

I used LMII's bridge drilling jig to place 6 perfectly spaced holes through the bridge for the strings about where the old strings came through. You can see the grooves that the strings left in the bridge which were filled with rosewood dust and thin CA. 

Then I hand sanded the bridge from 220 to 2000 grit to expose fresh wood which slightly alters the color of the wood because of the removal of the oxidized layer. Now the bridge should age and color uniformly which will help disguise my patch work

This guitar did have a spruce bridge plate so I drilled my holes, capped it with a piece of maple, and drilled through again. The maple cap helps protect the bridge plate from the ball ends of the strings hitting it and causing it to chip which compromises the integrity of it and leads to warped tops and lifting bridges.

The bridge area was properly prepped and the bridge is glued using fish collagen glue.

This is the front part of the bridge showing the other side that was filled, its barely noticeable but you can see the darker rosewood if you look close enough.

I ramped the saddle slots using a Dremel and a set of diamond bead reamer bits. Then I used an old bone saddle and some white plastic pins to complete the look of the instrument. The bridge is stable and should hopefully stick together for another 50 years!

Step 1. Don't

1960s P-bass I photographed at the Springfield, MO guitar show
Owner unknown (contact me for credit)

Why not?

Willie Nelson's guitar 'Trigger'
Image Credit: MentalFloss.com

Guitars are not like furniture in which a fresh coat of poly or shellac rejuvenates them and increases the value. With guitars it is actually more desirable for them to be worn in and show signs of age such as lacquer "checking" (the lines that appear in old finishes from age, temperature, and humidity). Vintage instruments are typically finished in nitrocellulose lacquer (which crackles in long lines) or shellac (which shrinks into cube-like shapes) which act quite differently than modern polyurethane finishes. Old instruments will get dinged and show that wear much more prominently than modern instruments and that is part of the charm.

People love to see the play-wear and the history that a guitar holds in its appearance and you would be erasing that by refinishing the instrument. 

There is a huge fad in the instrument world of "relic-ing" which is the process of taking a new instrument and trying to make it look like an old, well loved instrument. Relicing has its fans and opponents but it is usually always more expensive than an instrument without such a treatment. It often doesn't make sense to people outside the industry but its a serious money maker because the demand is there.

Value 

Instruments have value historically, monetarily, and sentimentally. I keep the original finish on every guitar I work on and recommend it to anyone who asks because a damaged guitar with original paint is worth more than a guitar with new paint. I've owned guitars with original lacquer that flakes off if you look at it wrong but I kept it the way that it was because of the value held in that original, flaky paint

Of course a vintage instrument in pristine,original condition will sell higher than one that has been worn-in but a refinished instrument will almost always sell for less than an instrument that has been worn-in naturally

For example, I have this 1970s Harmony-built Fender acoustic that is dirty, yellowed, and most definitely worn through years of being played and years of being poorly kept. It looks rough to most people but I wouldn't dream of refinishing it because if this is a $400 guitar, it'll be worth $150 after being refinished. It will lose its character and the history behind it.

The neck from the above Fender acoustic
*Note the carvings in the neck*

Amateur Refinishes

Of course I say this as a man whose website is entitled "The Amateur Luthier" but I tend to stay away from finish touchups or work unless the guitar has already been refinished before. It is typically my last resort to try and restore some value to an instrument or make it look somewhat original. As I mentioned above, a refinished guitar will almost always sell for less than an original guitar but it is also important to note that a poor refinish will sell for the value of the parts on the guitar. A guitar that has been refinished poorly with drips or unevenness or a terrible color choice can be worth as little as the value of the parts on the instrument.

If a guitar has already been refinished, you probably can't hurt its value by refinishing it again. The exception is, of course, with very old refinishes or ones that were done quite well.

Here is a 1966 Harmony H56 Rocket that has been refinished, poorly, with a wipe-on lacquer and has had some body work done to make it look like a double cutaway. These are normally $500-600 instruments but the refinish work makes it a $200 instrument.. The poorly done body work and refinish made it nearly worthless so I pulled the parts for use in a better quality guitar and sold the husk to someone who needs a neck and gave them the body for free.

This is a 1964 Hagstrom HIII that was originally sky blue but the finish was stripped down to natural and no finish was applied on top of that. The value of this instrument was tanked by the refinish and the lack of original parts made it nearly worthless. I sold the parts off and the husk to help revive other Hagstroms from the era because it wasn't worth the money to rebuild.

 

What do I do now?

Take it to a decent luthier (not a guitar tech that you would find at Guitar Center) and have them look it over to find an approximate value of the instrument. I've seen thousand dollar instruments that were stripped and became hundred dollar instruments. Especially during the "natural wood" fad of the 70s, that was a rough time for guitar finishes.

• Use guitar-oriented polishes to gently scrub dirt and grime off the guitar without losing original finish
• Do NOT use any automotive waxes or polishes 
• Do NOT buff the instrument with a machine unless you are very sure of what you are doing

• Has the instrument been refinished before?
• Yes, poorly with drips and runny paint
• Then it is likely well within reason to strip the paint and make the instrument look better
• Yes, quite well but its not my style
• Perhaps consider selling the instrument and buying another that suits your fancy. No need to ruin good work
• Nope but it is ugly/flaky/cracked
• Leave it alone, your instrument and wallet will thank you when you go to sell it. Plus you are keeping the decades of history and character 

If you are deadset on refinishing your instrument, consult with luthiers to get a price and find someone who is capable of doing good work.

If you are interested in doing it yourself, stay away from store-bought finishes (especially polyurethane!!) and find some good Shellac or Nitrocellulose. 

Here are some great resources for finding finishing supplies

https://www.stewmac.com/

https://www.lmii.com/

https://www.reranch.com/

http://www.madisonsmusicstore.com/finishes.asp