The Full-size Imperial (151 Series) is distinctive in styling and quality. The Imperial™ was first introduced in the 1970’s with its signature and futuristic Three-Step button, a fresh and funky design trademarked by Grover®. With 16:1 gear ratio.

The 151 Series is distinctive in styling and quality, the Imperial™ made its first appearance in the 1970’s. The most notable feature of this unique machine head is the futuristic Three-Step button, a fresh and funky design trademarked by Grover®.

  • Sealed-in, lubricated gears
  • 16:1 gear ratio
  • 25/64” post hole
  • Post length to hole: 22.2mm
  • Overall post length: 27.4mm
  • Weight per pc/per set: 1.8oz/10.8oz
  • Max. string gauge: .074”
  • Hardware included (bushings, screws)
  • Drop-in replacement for:
    • 152 Series

Available in:
For standard guitars, 3 Treble and 3 Bass, Set of 6
No. 151N Nickel
No. 151C Chrome
No. 151G Gold

Schematic Drawing

151 Series

AllParts Music Corporation

-Houston TX 77041United Stateshttps://www.allparts.com/

Australasian Music Supplies

-Melbourne VIC 3000Australiahttps://www.austmusic.com.au/

Guitar Center

-Thousand Oaks CA 91359United Stateshttps://www.guitarcenter.com/

John H Skews & Co, Ltd.

-Gaforth Leeds LS25 2HrUnited Kingdomhttps://www.jhs.co.uk/

Musicians Friend (Guitar Center)

-Medford OR 97504United Stateshttps://www.musiciansfriend.com/

Plus Music Products

-Thornville OH 43076United Stateshttps://www.ebay.com/str/plusmusicproductsonline

Skyway International, Inc.

-Exton PA 19341United Stateshttps://www.skywayint.com/

Skyway International, Inc. (sporthitech)

-Exton PA 19341United Stateshttps://sporthitech.com/collections/grover

Stewart-McDonald Mfg Co

-Athens OH 45701United Stateshttps://www.stewmac.com/

Sweetwater Music

5501 US Hwy 30 WestFort Wayne IN 46818United Stateshttps://www.sweetwater.com/

WD Music Products, Inc.

-North Fort Myers FL 33903United Stateshttps://www.wdmusic.com/

Warwick GmbH & Co – Austria

-- Austriahttps://shop.warwick.de/

Warwick GmbH & Co – Belgium

-- Belgiumhttps://shop.warwick.de/

Warwick GmbH & Co – Czechoslovakia

-- Slovakiahttps://shop.warwick.de/

Warwick GmbH & Co – Germany

-- Germanyhttps://shop.warwick.de/

Warwick GmbH & Co – Italy

-- Italyhttps://shop.warwick.de/

Warwick GmbH & Co – Poland

-- Polandhttps://shop.warwick.de/

Warwick GmbH & Co – Portugal

-- Portugalhttps://shop.warwick.de/

Warwick GmbH & Co – Spain

-- Spainhttps://shop.warwick.de/

Warwick GmbH & Co – Switzerland

-- Switzerlandhttps://shop.warwick.de/
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