Documenting history as well as my experiences with repairing and restoring vintage guitars.

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Style 1: Fig. 3, the most common Style 2: Fig. 2, a seemingly budget version Style 3: Fig. 4 for slot head instruments Inventors Harry St...

Safe-Ti-String Tuners

Style 1: Fig. 3, the most common
Style 2: Fig. 2, a seemingly budget version
Style 3: Fig. 4 for slot head instruments


Harry Stanley was born in January of 1895 in Harrison, Ohio to Franklin, a blacksmith, and Mary Stanley [1]. In 1920, Harry was working as a blacksmith likely with his father [2]. He continued in that field and was listed as a laborer in a steel mill in 1940 [3]. He died in 1966 [4]

Vincent J Moir was born in 1902 in Ohio to railroad worker Joseph Moir and wife Josephine [5]. In 1930, he was a proprietor of a shutter awning company and in 1940 worked in the laundry industry with a key-tag checking system [6][7]. He died in 1987 [8].

Harry Stanley, Secretary-Treasurer
of the Oahu publishing company
Image Credit: Vintaxe

The Patent

Original box

The objective of their patent was to propose a solution to two issues which guitar manufacturers and players were suffering from...
The first was that the advent of metal strings meant higher tensions than gut or fiber strings which led to strings slipping out of tune.
The second was that the ends of the metal strings were incredibly sharp and prone to cutting or stabbing the player or the instrument

Style 3 tuning machines with a string illustrating their use

Incomplete set of Style 2 tuners

Their solution was to design a tuning machine that accepted the sharp end of the string and protected the player from being injured. This tuner had a slot cut into the end of the post and a center hole drilled. Two variants were designed, one with a square slot and another with a triangular slot which became smaller as you approached the base. The string would then be cut to size, inserted into the post hole, and wrapped through the slot and around the post. The sharp angle of the slot would lock the string in place and prevent it from slipping as the string was tensioned. This would hide the string end, protecting the player, and also help keep the instrument in tune.


Original Saf-Ti-String tuners have the patent numbers and the design name stamped around one of the screw holes. So far I have not found any 'patent applied for' labelled sets. They only appear in the 3-on-a-plate configuration.

All signs point to these being manufactured by Waverly

Style 2 tuners

Guitar Prod. Co.

Guitar Prod. Co. was a stamp used on some of the tuners. Its unclear when

Guitar Prod Co, Style 3 tuners
Image Credit: Ebay - Lawman-Mike

Oahu tuners 
Image Credit: Reverb - Yooptone Music


The patent was set to expire in 1953 but Kluson had acquired the rights to the design prior to that date. Kluson began producing "Safe-Ti-String" tuners as early as the 1940s and they were available for most all models of tuning machine that they sold.

The modern incarnation of Kluson currently produces these tuners but refers to the design as the 'safety post' in their literature.

1950 Kluson Catalog Photo
Image Credit: Reverb - Izzy's Vintage Guitars

Kluson 'no-line' tuners with Saf-T-String posts
Image Credit: @notaluthier

Later Patents

Harry and Vincent also patented a set of classical tuners in 1935 using a modified version of their earlier Safe-T-String patent.

Classical Saf-T Tuners
US2094685A [10]

They also patented a metal bridge for acoustic guitars in 1936 which commonly appears on Oahu-brand instruments.
Metal Bolt On Pyramid Bridge