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May 31, 2020 - 6:33:49 PM
1245 posts since 4/13/2017

Does anyone know what the standard thread size is for planetary tuners? Ya know, for that nut that screws into the shaft?

May 31, 2020 - 7:08:43 PM

10827 posts since 6/2/2008
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I don't know the thread size, but the part is called a tuner bushing.  I did a lot of searching a year or so ago and found some on eBay that fit Schaller tuners but also came across some described as fitting Grover. Don't know if they were the same size.  Just trying to point you in the right direction if you're looking for a part.

Edited by - Old Hickory on 05/31/2020 19:09:13

May 31, 2020 - 7:29:43 PM

10827 posts since 6/2/2008
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To find the right part, you might need to search "threaded tuner bushing."

May 31, 2020 - 9:12:18 PM



712 posts since 4/12/2004

I presume that you're referring to the threaded bushing with a thin, hex head that fastens the tuner to the head stock with underside of the hex head clamping against the front of the head stock.

I have a very old Grover tuner, and the measurements I made of the thread on its threaded bushing suggest to me that the appropriate specification for the thread is 5/16-40 UNS-2A. The actual major diameter of the thread on my bushing is right on the low limit of the major diameter specified in the Unified Screw Thread standard (.3065").

I would be surprised if all tuners have fastening bushings that have the same thread profile.

Jun 1, 2020 - 3:48:46 AM



59 posts since 7/2/2004

I have restored some prewar planets and made a grease fitting to match the threads so I could put grease back in it worked quite well.If I remember the thread was a very good match from a british thread series
maybe (model engineer) or similar I'll have a look in the shop and get back as they say watch this space.

Jun 1, 2020 - 7:40:47 AM

13018 posts since 6/29/2005

a lot of them are metric and close to 5/16-40 and look the same, but no cigar.  I have Grover Rotomatic tuners where the threads are different than other Grover Rotomatic tuners, and aren't compatible with some  Les Pauls, and 5-Star banjo tuners that aren't interchangeable with other planetary tuners.

Also the lengths differ and some won't fit on all pegheads—for example, I restored a '62 Vega PS5 to "60s folksinger setup" and the more modern Grover Rotomatics had bushings too short to meet the female part on the tuner body due to the thickness of the peg head—I had to pirate vintage ones from a guitar I have after trying numerous bushings I had in the shop (that's how I learned they are all over the map).

The original ones on the Grovers on my '27 Granada are 5/16-40, and I'd guess that must have been the standard back then but things change.

Edited by - Ken LeVan on 06/01/2020 07:43:05

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