This is one of the smallest heads in the Criterion line featuring a 7/8-20 threaded back. The square design permits an extremely large offset while maintaining a more than adequate bearing surface. The interchangeable bar holder comes with either a 3/8" or 1/2" hole.

The dial face of the micrometer adjusting screw is graduated for direct reading, i.e., an advance of .001 on the screw removes .001 from the bore. All Criterion Boring Heads have a rust resistant black oxide finish on the body, combined with a satin chromed bar holder and dial screw.

Available with either a 3/8 " or 1/2 " hole in the bar holder, this head fills the need for a small boring unit capable of producing extremely accurate holes. All bar holder bearing surfaces are ground after hardening for long life and trouble-free operation.

Like the S-1-1/2, it comes with a 7/8-20 threaded back for use with a variety of shanks and it also features a direct reading dial screw.

It performs equally well for heavy roughing cuts on turrets or fine finishing work on mills and jig borers.

This S-3 Boring Head is the forerunner of all Criterion heads. With the exception of the bar holder, this unit has changed little in the past 60 years. Its practical simplicity and proven performance have consistently made it a big seller in our line.

The advantages of a square design are seen in the extremely wide base and the 1" hole capacity for boring bars and tools.

The latest improvements are a cone-shaped bar holder and the addition of a direct reading dial screw.

A 1-1/2-18 threaded back permits the use of any of the 1-1/2-18 threaded shanks listed in the V-Flange & BT Shanks and the Shanks & Adapters sections.