Standard Tuning Machines (Keys, Tuners) for Upright Bass

Plate-Style: This is a pair of plated tuning keys with each pair mounted to a heavy gauge, traditional style brass plate with ornamental edge engraving. They are 24:1 gear ratio, designed for ¾ sized basses. These are are made in Germany and include a full set of matching screws. Sold as a pair only.

There is no "standard size" for tuners, and they can vary by manufacturer - please MEASURE your bass' current machines (or holes in the pegbox) to ensure that the plated machines will fit before you order! It's also not uncommon to have to "widen" the holes to accommodate slight differences.

These should fit most, if not all, Engelhardt 3/4 size basses (and possibly some later-era Kay basses), as they are the same ones that Engelhardt installs as original equipment on their basses. (Though it is prudent to check, as Engelhardt and Kay were known for occasional variations from the norm, depending on parts availability.)

Key Measurements:
Roller at hole: .56 inches
Distance between holes, center to center: 3.75 inches
Post Length: upper 1.75", lower 2.13



Individual Keys, Set of Four: These are a complete set of four tuning keys designed for separate (non-plate) mounting. They have a 27:1 gear ratio, and are designed for ¾ sized bass. These are are heavy-duty machines made in Germany, and a full set of matching screws is included. Each individual machine weighs approximately 6.2 oz. (weighed on our postage scale).

Approximate Measurements:

• Roller at hole: .56 inches
• Plate size: 1.8 x 2.25 inches
• Screw hole distance: 1.25” on the short side and 1.75” on the long side
• Post length:
• Long: 2.25 inches measured from the back of the plate
• Short: 1.87 inches measured from the back of the plate
• Tuning key shaft length:
• Long: 1 inch, measured from plate edge to beginning of key
• Short: 0.5 inch, measured from plate edge to beginning of key