Specification:
Model: CAT40
Type: CAT40 Shell Face Mill Holder

Max. RPM Balanced to: G6.3 15000

Material: Hardened Steel
Finish Type: Unfinished
End Cut Type: Flat End
Cut Type: Center Cutting
Bore Dia. in Shell mill: 3/4"
Gage Length: 4"
Shell mill pilot T.I.R: <0.0002" 
Drawbar Thread Size: 5/8×11UNC
Nose Diameter: 1.75
Arbor Diameter: 3/4
Arbor Screw Diameter: 0.56
Key Width For Face Mill Keyway: 0.31
Color: Silver

Product Function Description:
This product has undergone rigorous quality testing.
Durable and easy to install and replace.
The most cost-effective and best after-sales service.
Quality assurance that gives you peace of mind.

Features:

Dynamically balanced to 15,000RPM at G6.3 at all location for consistent balance.
H6 arbor tolerance to improve cutter chattering and overall cutting tool life.
T.I.R. 0.0002" measured from CAT40 taper to face and arbor.

Unique design feature in the flange to minimize the off-balance nature of CAT 40 taper specification.  On the side of flange where a half spherical hole is located, a "wall" is built around this hole to compensate the weight of the metal chips lost from forming this spherical hole.  This design allows the left side and right side of the holder to achieve 50-50 perfect weight distribution in its upright position, like the position inside a machine spindle.  Symmetrical design in evenly weight distribution will minimize centrifugal force in high speed spinning and thus maximize the holder's ability to hold the cutting tool concentric to spindle rotation.
Made from alloy steel harden to 54-60 HRc.
Taper ground to AT3 or better accuracy standard for maximum contact with spindle.  
Most consistent gaging for tool holder shanks.
All critical surface are precision ground.

Would hold its accuracy over longer period of time.

Using as coolant shell mill holder with face mill coolant style arbor screw 202-6294.

Package Includes: 
1PC CAT40 3/4 × 4" Shell Face Mill Holder Adapter