GB/T 6139-2007Subland twist drills - Technical specifications (English PDF)

1 Scope

This standard specifies the ladder twist (general level and precision) of size, material and hardness, appearance and surface roughness, marking and packaging

Technical requirements.

This standard applies to press GB/T 6138.1 and GB/T 6138.2 produced before tapping drilling ladder ladder twist and other hemp

Flowers diamond.

2 Normative references

The following documents contain provisions which, through reference in this standard and become the standard terms of dated references, all subsequent

Amendments (not including errata content) or revisions do not apply to this standard, however, encourage the parties to study under this agreement is standard

Whether the latest versions of these documents. For undated reference documents, the latest versions apply to this standard.

GB/T 1442 straight shank tools with drive flat tail and sleeve dimensions and tolerances (GB/T 1442-2004, ISO 4203. 1978,

MOD)

GB/T 1443 from machine tools and tool handles with clip cone (GB/T 1443-1996, eqv ISO 296.1991)

GB/T 1804 General tolerances for linear dimensions without individual tolerance (GB/T 1804-2000, eqv ISO 2768-1. 1989)

GB/T 6138.1 before tapping drilling stepped twist drills - Part 1. Straight shank twist ladder types and dimensions (GB/T 6138.1-2007, eqv ISO 3439.2003)

GB/T 6138.2 before tapping drilling stepped twist drills - Part 2. Morse taper shank twist ladder types and dimensions (GB/T 6138.2-2007, eqv ISO 3438.2003)

3 Symbol

4 Dimensions

h9, precision h8.