String Lifter (Bridge Jack)

Plans used were those from "Bridge Jack Construction" by E.L. Wolfensberger as published in the SCAVM Bulletin in November 1993 and displayed on their website at They are primarily for making one mainly from wood, but being used to making things from metal I decided to make the body from an off cut of 5/16" aluminium plate (from Geraldton Boat Builders Pty Ltd.) The guides are from approx. 1/8" nails, the screw 3/16" with Whitworth thread, and knob from 3/16" steel scrap to hand (only because I had no aluminium in that thickness.) and a piece of leather from a worn out garden glove for the base.
The only tools required are a hacksaw, drill (preferably a drill press) flat and round files, sandpaper and a 3/16" tap.
In retrospect the screw length could be shortened and the knob made from thinner or lighter material, as the force needed to rotate the screw for lifting the strings is minimal.

Exploded view

Front view

Side view

Front of bridge

Back of bridge

This page was last updated  on 07 April 2004