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Table 37 MILLSHRED Plain Round Inserts RC..T…MO. Basic Feeds, mm/tooth
Basic starting feed fzo, mm/tooth, for inserts

ap/r Ø12 Ø16 Ø20

ap fzo ap fzo ap fzo
– 0.15 0.56 0.15 0.75 0.15 0.9
1/16 0.37 0.5 0.5 0.68 0.62 0.83
1/10 0.6 0.41 0.8 0.55 1 0.67
1/8 0.75 0.36 1 0.47 1.25 0.57
1/4 1.5 0.26 2 0.34 2.5 0.42
3/10 1.8 0.24 2.4 0.32 3 0.39
1/2 3 0.18 4 0.25 5 0.3
5/8 3.75 0.14 5 0.19 6.25 0.23
3/4 4.5 0.14 6 0.19 7.5 0.23
7/8 5.25 0.14 7 0.19 8.75 0.23
1 6 0.14 8 0.19 10 0.23
The feeds relate to workpiece material groups 1-9 (plain carbon and low alloy steels).
For machining groups 10-11 (high alloy and tool steels) the table values should be
multiplied by 0.7, for machining groups 12-13 (ferritic and martensitic stainless steels) – by 0.85.
- Recommended depths of cut
Tool overhang
The overhang (or the projection) of a milling tool is an important factor of the tool stiffness and
machining stability. The tool overhang being 5% less reduces the tool deflection by 15%, 10%
less –by 27% and 20% less – already by 50%. Minimizing the overhang substantially improves
operational efficiency, allowing for increased cutting conditions and good surface finish.
But, what can we do - manufacturing real parts often demands long tools. How to determine the Milling Tools
cutting data for such tools? And what is a high overhang, for which various techniques of cutting
data determination recommend correction factors?
This not simple question is directly connected with the dynamic behavior of a tool. It relates to the
sphere of serious research and needs a separate discussion. We are sure that the reader on
the basis of his own knowledge and experience knows exactly if the overhang of a tool that he uses
is high. For a rough estimate, the following rule of thumb often can be helpful: the overhang is high
being 4-5 and more times as much as the nominal diameter of the tool. However, one thing needs
clarification: from which point should the overhang be measured?
Generally, in case of the shell mills mounted on arbors, the correct way is to measure the overhang
for the whole assembly, which is to say from the gauge line (datum) of the arbor shank (Fig. 9).
For the endmills that are clamped into holders with spring collets or adapter-style holders
with side screws, the overhang is measured from the holder (Fig. 10).

ii. MILLSHRED serrated round inserts
As previously noted (Table 33), the serrated round inserts are intended first of all for the
following cases:
• High depth of cut (above 15% of the insert diameter)
• Considerable tool projection (the overhang more than 2.5 of the tool diameter)
• Milling near thin walls
• Poor workholding
Additionally, the serrated inserts are sometimes applied in milling with usual depth of cut
(to 15% of the insert diameter) when the main drive power of a machine tool is limited.

A programmed starting feed per tooth fz is defined by equation (8):
fz = fzo x KH (8)

Where: fzo – the basic starting feed (Tables 39-41)
KH – the overhang coefficient (Table 38)

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