Gun drill geometry is not one specification. Construction identifies the materials and joints; the nose grind defines the cutting end; peripheral form defines the head’s circumferential arrangement. These fields can differ independently.
Begin with the construction, then identify the geometry
The botek catalogue, pages 6 and 14, distinguishes a solid-carbide head-and-shaft body from a brazed head on a steel shaft. Its pages 15–17 then discuss cutting-end and peripheral forms within named tool families. An “indexable,” “brazed” or “solid-carbide” label does not by itself specify the grind.
| Field | Question it answers |
|---|---|
| Construction | Which materials, joints and replaceable elements form this tool? |
| Nose-grind designation | Which supplied cutting-end geometry is intended? |
| Peripheral contour | How are the head’s guide/contact surfaces arranged? |
| Fluid-channel form | Which internal supply passage is present? |
| Driver and working length | How does the tool connect and reach the feature? |
This distinction is useful for both a new order and a service record. A nominal diameter can agree between tools while these fields remain different.
Read grind designations within their named family
Page 6 gives SA-0009 for the Type 113 range 0.500–4.000 mm; page 15 gives SA-0001 for Type 110 at 1.850–4.000 mm. The overlapping diameters do not make those designations interchangeable. These are catalogue examples identifying different families, not a recommendation to choose a grind from diameter alone.
The catalogue relates nose-grind changes to chip formation, bore bottom, fluid behavior and bore results. Its peripheral-contour discussion concerns the head’s contact with the wall. Specifying one does not complete the other. A complete tool identity should retain both supplied designations, including any drawing-defined modification.
Why a geometry measurement needs its method
On page 16, botek cautions about measuring diameter on particular peripheral forms. An asymmetric head cannot automatically be evaluated as though every direction presents the same two-point contact geometry.
Retain which feature was measured, its orientation and the applicable method. “Tool diameter checked” without that context may describe a different quantity from the supplier’s controlling dimension. Likewise, a photograph can locate a chip or worn region without measuring the delivered cutting geometry.
A service change is a geometry change only when identified
A nose regrind, replaced cutting insert and replaced guide element are different operations. Record the serviced feature and returned specification. Do not treat the name of a construction family as a universal grinding instruction.
Use the RFQ worksheet for those identities, then guide-pad contact for the bore-wall mechanism or regrinding for preserving the tool’s intended geometry across service.
Revision note
October 8, 2026: revised the technical explanation and connected reading after source review. Original publication date and URL retained.
