Stiff tuning machines

[Old Jawbone]

Hi everyone,

I'm looking for some advice on loosening up machine heads. I have a set of Schallers that's very tight, particularly on the wound strings. They're quite difficult to turn and seem to be getting worse over time. Can anyone help me?

Thanks!

[sunburst]

In my experience, Schallers can be like that; worse than other tuners. Usually, it's not the tuner, but instead, the installation.
With mandolin tuners, you have four tuners on one plate. If the holes for the four shafts aren't in a straight line, and the correct distance apart, it forces the shafts out of alignment with the plates, and binds the gears.
If you remove the tuners from the mandolin, be sure they are clean and lightly lubricated, then slip the shafts through the bushings in the holes, they should "drop" in with very little resistance. If they don't the holes are out of alignment and need to be adjusted by plugging and re-drilling. There are some quick and dirty ways to improve alignment involving duct tape or something like that, but the real fix is holes that line up and are spaced correctly.

If the tuners are clean, lightly lubed, and the holes are correctly aligned, and the tuners are still too tight, you've probably got a bad set of tuners, and there should be a warrantee of some sort.

There's also a thread on here somewhere about lapping the gears with compound, toothpaste I believe, and that might help if the gear mesh is too tight.

[Old Jawbone]

Thanks John. I'll investigate those possibilities.

[Paul Hostetter]

I have a few pages about tuner maintenace and so on here (http://www.lutherie.net/tuner.maintenance.html). Have a look, they might help.

http://www.lutherie.net/tri.flow.jpg

[Old Jawbone]

Thanks Paul. Lots of great advice on that page.

[Paul Hostetter]

It's a work in progress, I'll try and get a few more good photos up there.