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- Technical Information
- Drill features and specification
- Web thinning
DRILL FEATURES AND SPECIFICATION
WEB THINNING
The rake angle of the cutting edge of a drill reduces toward the centre, and it changes into a negative angle at the chisel edge. During drilling, the centre of a drill crushes the work, generating 50–70% of the cutting resistance. Web thinning is very effective for reduction in the cutting resistance of a drill, early removal of cut chips at the chisel edge, and better biting.
| Shape |  X type |
 XR type |
 S type |
 N type |
|---|---|---|---|---|
| Features | The thrust load substantially reduces, and the biting performance improves. This shape is effective when the web is rather thick. | The biting performance is slightly inferior to that of X type, but the cutting edge is hard and the applicable range of work is wide. | Cutting is easy. This shape is generally used. | Effective when the web is comparatively thick. |
| Major Applications | General drilling and deep hole drilling. | Long life. General drilling and stainless steel drilling. | General drilling for steel, cast iron, and non-ferrous metal. | Deep hole drilling. |
