Improved Counter-Racking for Vises | Popular Woodworking Magazine

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A few years ago I was writing about Bench vice made of Ha-Khoret wood and its built-in feature that prevents the infamous jaw racking syndrome. Vise rack occurs when clamping a workpiece to the right (or left) side of the jaws and when tightening the screw, the movable jaw rotates in the opposite direction. This condition prevents the workpiece from being properly clamped and also puts a lot of destructive force on the clamp mechanism. There are some shop-made masks you can build and insert between Jews to compensate for the asymmetrical clamp, and there’s this Lee Valley mask too. But the integral feature of Ha-Khoret is still the most impressive solution I’ve ever seen.

An industrious reader, John Adams, took up the challenge and came up with his own take on the Ha-Khoret jig. John’s concept is interesting and can work well for many vices. He replaced the cast iron threaded knob with a mahogany knob which was built around a threaded rod. Most of the time the mahogany knob nestles in a countersunk hole in the stationary jaw of the vices. But when John needs to clamp a narrow or vertical piece on the left or right sides of the vise, he can easily open one of the knobs to balance the clamping pressure.

Its knob consists of a mahogany cup and a threaded rod that slides through a T-nut that is anchored to the side of the workbench. The knob can be turned in or out of the counterbore with ease. John made the cup and knob lid using a hole saw. The 3/8 ″ threaded rod passes through the lower cup and is attached to it by a metal pin. The head of the threaded rod is tightened onto the cup with a nut and then surrounded with epoxy. Finally, the cup is covered with a round disc in the shape of a mahogany lid.

John drilled two center holes through the blank side of the knobs. These holes served to guide the drill which pierced the threaded rod which was glued into the cups. Then a pin was inserted through the hole and into the threaded hole to ensure the integrity of the union between the threaded rod and the mahogany knob.

A hole saw was John’s favorite tool for shaping knob cylinders.

T-nuts are incorporated into the left and right sides of its fixed cast iron jaw.

Note that John has foreseen the challenge of slipping his smooth round wooden knob from his nesting site. To help engage the hidden knob, it has pre-drilled an eccentric hole that houses a nail or awl to initiate rotation of the knob.

Below I have sketched out some alternatives to John’s design for those who prefer to use ready-made hardware or agree with the cast iron jaws of their vises instead of dealing with T-nuts or inserts.

In option, (A) I show a way to build the knob with a long bolt glued into the cup. Sketch (B) is intended for those who wish to use a ready-made knob instead of a wooden cup.

And in option (C) I show how to install this support jig on a vise with metal jaws.

  1. First, drill a large hole in the stationary wooden axillary jaw to accommodate the store-bought threaded pin knob.
  2. Drill and tap a second hole in the center of the first to allow the knob to go in and out.
  3. A “+” or a six-winged Knob with threaded pin it will be better here as it will be easy to hide it in the counterbore hole and extend it as desired.

In this latter drawing (A1) the knob head is made similar to John’s idea, but instead of a locking pin, I secured the knob with a nut and washer that inserted the assembly from the inside.


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