Page 1041 - Tungaloy Catalog

Technical Reference
Drilling Tools
Chip shapes

d Chip shape produced with central insert
• A conical coil shape whose apex point coincides with the rotating cen-
ter of the drill is the basic shape. The chips are broken into small sec-
tions with increases in feed. However, excessively high feed causes
the chip to increase in thickness and develops vibration which dis-
turbs stable machining.
• In TDX drills, marked chips shown below are the most preferable
shapes. This type of chip is broken into adequate lengths by centrifu-
gal forces when used in tool-rotating condition. On the other hand,
when used in work-rotating condition such as on a lathe, a continu-
ously long chip is often produced without entangling.

d Relation between chip shapes and feeds (For of central insert)

Carbon steels, alloy steels, etc. Low carbon steels, stainless steels, etc.

Higher

Feed

Lower Technical Reference

14
d Example of chip shape in work-rotating applications (For case of central insert)
(ø26, S45C, Vc = 100 SFM, f = .004 ipr)

3.937 in

14–23