NPA 03/2017 INCH


DCNT – New SUMOCHAM Pre-Thread Hole Drills


As pre-thread hole drilling is very popular in many industrial tapping applications, ISCAR is upgrading the DCT CHAMDRILL family to similar drills that carry the more advanced SUMOCHAM drilling heads.

The new drills were designed for 3/8 to 7/8” UNC and UNF standards pre-thread holes.

There are two main applications for pre-thread hole drilling:

1. Drilling pre-thread blindholes:
Drilling with a 45° chamfer
Counter boring

1. Drilling pre-thread throughholes:

Drilling with a 45° chamfer
Counter boring

The new DCNT drills carry two standard chamfering inserts designated AOMT 060204-45DT IC908, symmetrically mounted so that the cutting forces are balanced for optimal performance.

Chamfering Inserts
The AOMT 060204-45DT IC908 chamfering inserts were designed for chamfering on a wide range of materials with optimal chip formation.

The new AOMT 060204-45HD IC908 inserts were designed for chamfering low carbon steel and soft materials.

  • Can be used on a wide range of workpiece materials
  • Can be used for blind, as well as through hole applications
  • No vibrations during chamfering due to a balanced drill construction
  • Provides diametric versatility – SUMOCHAM is capable of using a range of drilling heads on each drill body. This provides a substantial advantage for users who change drills for the same tap operation. The user may use the same DCNT drill for ISO “M” (coarse pitch thread) and for ISO “MF” (fine pitch thread). Attached are tables containing the many possible combinations.

DCNT (M8-M24) Indexable Head Drills with Chamfering Inserts Mainly for Pre-Thread Holes
• Hole tolerance: D+.002" in average conditions. However, it can be higher or lower according to machine and tooling conditions
• Do not mount smaller drilling heads other than the specified range of the drill body.

(1) Used for standard thread size
(2) Pre-thread hole diameter
(3) Cutting diameter minimum
(4) Cutting diameter maximum
(5) Seat size code

Chamfering Inserts
• The cutting speed is dependent on the drilling insert being used.
(1) For low carbon steel

1. Drilling pre-thread blindholes:
Drilling with a 45° chamfer
1. Drilling pre-thread throughholes:
Drilling with a 45° chamfer

Pre-Thread Recommended Hole
Diameters with DCNT Drills

Material Groups
• When using external coolant supply only, reduce cutting speed by 10%.
• Use internal coolant supply when machining austenitic stainless steel.
• When using more than 5XD drill ratio, reduce cutting parameters by 10%.

Material Groups
Recommended cutting data
(1) For workpiece materials list, see pages G6-41. As a starting value, the middle of the recommended machining range should be used.
      Then, (according to wear results), conditions can be changed in order to optimize performance.
      The data referse to IC908.
利用規約及び販売条件(英語)    プライバシーポリシー
© ISCAR JAPAN LTD., Metalworking Tools ( All Rights Reserved.