Tool Selection Guide
Choosing the Correct Small Hole Boring Bar
2 Determine boring bar (D).
A Select shank size (D) based on your
machine’s requirements.
B Determine bore depth (how far the
boring bar extends from the holder).
Multiply bar diameter by 4. If bore depth
is less, use a steel bar. If bore depth
exceeds 4:1 ratio, use a carbide bar.
Use L1 or L4 depending on bar selected.
C A
B
(See recommended maximum overhang
chart on page D86.) For indexable tooling,
go to step 3 . For all other
tooling systems, go directly to step 4 .
C Determine lead angle (KRA) . Zero
degree lead angle is used when maximum
stability is required. Lead angle may vary
based on changing conditions, such as
boring in a blind hole.
3 Determine which chipbreaker is best
for the material to be machined.
Consult the Small Hole Boring Chipbreaker
Geometry charts on pages D34–D37.
4 Determine which grade is best for the
material to be machined.
D6
widia.com
Consult the Grades and Grade Descriptions
charts on pages D38–D39.