Variations of Grover Rotomatic Tuners Commonly Installed on Gibson Guitars
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Like many people, I've had a ton of Grover Rotomatic tuners on various guitars. At one point I had a huge bag full of them all at one time. As is my habit when I have the opportunity, I got out my camera and photographed them all.
These pictures and words are just for visual reference. I make no claim to be an expert on these tuners and I don't know for sure when things transitioned from one model to the next. Hopefully I can get some feedback and I'll update this page when I accumulate some definitive information about that.
Made In USA Grovers
Many people think these are the 'best' ones; I disagree. I'll explain at the bottom of this page. While there were certainly other versions of the Grover Rotomatics with different tuner buttons and gear covers, the most common by far were the versions shown below with the 'kidney bean' buttons.
The USA-made ones were 12:1 ratio and came in a different-shaped casing than the Orient-made Grovers. Below are the earlier 'Pat Pend' and then the slightly-later 'USA' model. The cast bushing that slides up into the headstock is 3/8" diameter, smaller than the Orient-made Rotomatics. The diameter of the string post is also slightly smaller than the later Rotomatics, and the thread on the screw-in bushing is different than later Rotomatics. They also had different size and shape washers for the face of the headstock. On these models, notice that the word 'Grover' is cast in raised letters on the front of the casing:
'Pat Pend'
'USA'
Orient-made Grovers
I can also make a case that the folks at the original Hamer facility may have had a bunch of old stock they were using, similar to their use of original old PAFs in some of the early Hamer guitars.
The point is, I don't know for sure when the transition to Orient-manufacture occurred.
Some changes took place when the production moved to Orient. For example, the gear ratio changed from the 12:1 ratio of the USA-made Rotomatics to a 14:1 ratio. Notice the difference in the shape of the casting at the top - it's flush with the surface of the headstock, versus rounded 'milk bottle' like the USA-made ones. The diameter of the cast bushing is now 10mm, the diameter of the string post is slightly larger, and the thread on the screw in bushing is now different. Also the very first generation have the word 'Grover' cast in recess and no letter cast into the back of the casing.
These Grovers are the early Orient-made version:
These are the most recent Orient-made Grovers I've had. At the time I had them, they come in both 14:1 and 18:1 ratios. The word 'Grover' on the front is back to being cast in raised letters, and a letter (randomly, A through D) cast in the back.
The 'older Grovers are lighter' myth. Many people believe the older Grovers weigh less than the more-recent Grovers. Nope! Old 'USA' Rotomatics
Recent Orient-made Rotomatics
Screw-in Bushing and Washer Variances
This photo shows the differences in the screw-in bushings and washers over the years. The two on the left are from Orient-made Rotomatics, and the two on the right are from USA-made Rotomatics. Because of the differences in overall diameter, thread, and string post diameter, the bushings from the USA-made and Orient-made Rotomatics cannot be interchanged.
Also, in my admittedly limited experience, the size and profile of the headstock face washers varied. I suspect that was at the request of the individual guitar company at the time the order placed. Just a guess.
String Post Height Variances
This photo shows that there are some Grovers out there with taller string posts than others. In the picture below, the nickel tuner has a string post that is the height that would be found on most Gibsons, and many many other guitars. The gold tuner has a slightly taller string post, obviously. My guess is that these were intended for instruments with a thicker headstock. Can they be used on a Gibson? Of course. However, a little bit of string break-over angle will be lost at the nut. I can't say if anyone would hear a difference or not. Just posting this for information - something to pay attention to when purchasing used Grovers.
Also, so as to not confuse anyone, the black item behind the tuners in this picture is not meant to represent a guitar headstock; it's just a piece of plastic I set them against for the picture to help illustrate the difference in string post height. Its thickness is meaningless.
Another Old Version
Earlier in the life of this page, a good friend gave me a set of Grovers to add for the fun of seeing them. These tuners are the original version of 'Model 103'. There is a reissue version of 'Model 103' available these days, but it's not really a true remake.
This photo shows the front of tuner. At a quick glance, it's shape is moderately different than the Grover model we're most-familiar with. The gear cover has both the 'Pat. Pend.' and 'U.S.A.' lettering embossed on it.
The real difference is shown when looking at the edge of the casing - it's two-piece!
The back plate is flat and attached by peening down bosses from the front casting that protrude through holes in the back plate.
This particular set has kidney bean buttons, but it was also available with pearloid buttons and who knows what else. I personally have never seen a set on a Gibson guitar, at least that I remember. If anyone can tell me which guitars they've seen this model on, please let me know and I'll add that information to the page.
As promised, here's which model I like the best: I prefer the first-generation Orient-made Rotomatics. They have a more-modern gear ratio, and usually have MANY less years of wear on them than the original 'USA' models when found on the used market. To my eye, they also have a better-looking nickel plating that more-closely resembles the plating on the original 'USA' models. The most current Rotomatics have weird-looking, overly-shiny nickel plating that I find unattractive, and it doesn't 'relic' very realistically.
Thanks for looking.
Notice 'USA' lettering is no longer stamped into the gear cover, along with the 'Pat Pend' lettering. The 'USA' lettering is now cast into the back of the casing:
