SHANK SIZE: NT-40, BORING HEAD SIZE: BC-3.
Capacity: 0.39″ (10mm) to 8.66″ (220mm).

Here is a sturdy unit of extended boring range,
capable of peeling off heavy roughing cuts as
well as a tool of extreme sensitivity.
The use of a wide base bar holder, resting
securely on the body, eliminates the need for a
separate side plate. You will note this has now
become an integral part of the body.
The direct reading adjusting screw is ground
after hardening and a plainly marked dial face in
and adjustments of 0.01 or less.
All Criterion Boring Heads have threaded backs
for use with a variety of shanks. This model
takes a 1-1/2”-18 threaded shank.