stubborn tuners

[Gary S]

I have some tuners that operate very smoothly when they are off the mandolin but when installed a couple of the tunning pegs become very hard to turn. What causes this?
Thanks...Gary Silverstein

[sunburst]

Usually poorly aligned or poorly spaced holes in the peghead.

If the tuners holes aren't spaced the exact same as the tuner shafts, and/or are not in a line as straight as the shafts, the shafts are forced in different directions and out of parallel when the tuners are installed. That causes hard turning.

[Gary S]

If the tuner shafts rub against the bushings rather than pass by smoothly this could be causing my problem? Would you possibly reccomend drilling the hole in the peghead slightly larger?
Thanks for the advise...Gary

[sunburst]

If you just drill larger, the bushings won't fit. If you can get larger bushings, The holes will still be misaligned. It might be possible to ream the holes with the type of reamer that only cuts on one side so that you can "push" the hole in the right direction and then install larger bushings.

Actually, it is not the friction with the bushing so much as it is the gears and shafts in the tuners being put into a bind by the lateral preasure of the hole misalignment.

[John Flynn]

I had the same problem with my beater mandolin and determined that the cause was that the holes were not aligned. I tried lubing the tuners to no avail. Then I did something that the luthiers on the board will likely cringe in horror at, but it worked like a champ. WARNING: This was done by a complete amatuer! Only try this at home at your peril!

I removed the bushings and widened the holes with a drill bit slightly larger than the holes. I didn't have a reamer, unfortunately, as it would have made the job a lot easier and neater. Then I used the tuners themselves as an alignment tool to "glue" the bushings back in with a coating of plastic wood around the sides of the bushings. When the plastic wood had just set up a little, but was not yet hard, I used a dental pick to remove the excess from both the front of the headstock and the back of the bushings through the back of the drilled holes. When everything hardened, I put it all back together and the tuners worked very smoothly. The job looks OK, but there are some appearance flaws you can see if you look closely. I am going to do some finish re-touching that will take care of that. I know what I did wrong and think if I had it to do again, I could make it look perfect without the re-touching.

[peter.coombe]

The easiest way to fix this problem is to ream the hole in the direction you need to align the string posts properly, then insert a wood shim into the hole to move the bushing into the correct place. The bushings will then fit nice and tight. To work out what you need to do, look at the string posts from the side. They should be vertical, not leaning towards the nut or away from the nut. Unfortunately, poor fitting of tuners is an all too common problem.

[sunburst]

Unfortunately, poor fitting of tuners is an all too common problem.
Yep. It's not easy to drill four holes in perfect alignment every time. And if we do, we assume that the tuners will be perfectly spaced.

[Rob Grant]

I use a homemade steel jig to drill the holes in my mandolin pegheads. This helps "get it right," but you can still have problems if the front and back peghead surfaces aren't perfectly parallel with each other.

[TommyK]

Mando Johnny,
Now that's good old Yankee Ingenuity! A little retouch after the first attempt? I'd call it a success. From reading the other suggestions and yours I'd pick yours as the best.
Wood is not a highly precise material to be working with as it is resilient (soft) and moves with humidty --- as compared to steel. Then you drill close fit holes for a metal tuner to fit into. I'd say misalignment and interference leading to binding are a given.

[sunburst]

I use a homemade steel jig to drill the holes in my mandolin pegheads. This helps "get it right," but you can still have problems if the front and back peghead surfaces aren't perfectly parallel with each other.
Yep, jigs with drill bushings work.
For the interested, the method that Bob Benetetto describes in his archtop guitar book is the method that I use. I like it better than the drill bushings for a couple of reasons, one of which is, it's easier to use a Forstner drill bit and get the resulting cleaner holes.

The peghead front and back do not have to be parallel. Mine, and for that matter, Gibson's before sometime in the 50s are tapered toward the end. (I'm not sure about the new Gibsons.)
The holes have to be drilled square to the back of the peghead.

[Rob Grant]

Problem is that, in my case,the face of the peghead is flat. The back of the peghead often slopes slightly up to the narrow portion of the neck (for strength near the truss rod pocket). In this situation drilling from the back is not on. With four-on-a-plate tuners this variation does cause binding in the two tuners closest to the body. Here's a small image of the solution I use. When the tuners are installed, the inset looks rather nice.

[TommyK]

Rob,
No that's the way they shoulda done it at the factory.
Nice wood work! Do you have a pic with tuners installed?

[sunburst]

Oh Yeah, I'd forgotten about that! When building, I've learned to check with a straight edge to be sure that the back of the peghead is flat for at least the length of the tuner plates.
The curve into the neck shaft can't start until clear of the tuners without some binding, or a solution such as yours.

[Rob Grant]

TommyK,

Here's a photo with tuners installed...