Taft-Peirce hardened Tri-Blocks are tools of exceptionally high precision. They offer the ultimate in both quality and accuracy.

The extremely versatile 1" x 2" x 3" size of Taft-Peirce Tri-Blocks save so much time and money that the modest initial investment is often recovered in a matter of days. Typical uses include surface plate setups for layout and inspection jobs, and accurate positioning of work on jig borers, jib grinders and other machine tools. These Tri-Blocks are also extensively used for sine angle applications and with optical comparators.

Unlike many "1-2-3" blocks now on the market, these Taft-Peirce Precision Tri-Blocks are so accurate that the maximum error that can exist between any two is 0.0001" on "Inspection" grades and 0.0002" on "Toolroom" grades. Because of these unusually close tolerances, where "matched" sets are required, you need only order "Inspection" grade in whatever quantity is desired to make up a particular set.


Style 9151 Precision Tri-Blocks are made of the finest quality alloy steel, scientifically heat treated and hardened to Rockwell "C" 63-65 for maximum stability and wear life. They are of solid construction precision ground on all six sides (within the limits of size and parallelism specified in the accuracy table) to a uniform 8 micro inch finish or better.

Style No. Overall Dimensions Grade Accuracy Price
Height Width Length Squareness All Surfaces Within Parallelism All Surfaces Within Size Within
9151-1 1" 2" 3" Toolroom 0.0002" 0.0002" 0.0001 $208
9151-2 1" 2" 3" Inspection 0.0002" 0.0001" +.0001

Automation and Metrology 130 Liberty Street Painesville, Ohio 44077
Phone:  (440) 354 6436  Fax:  (440) 639 9983