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Standard retention knob, CAT50, 1"-8, 45°, Coolant through; O-Rings included

Retention Knob Information and Installation (PDF)

Retention Knob Installation Video

Category: Retention Knobs
Thread Size: 1.00-8
Angle: 45
Knob Diameter: 1.140
L1 Length: 0.7000
L2 Length: 1.000
Flange Thickness: 0.200
Hole Diameter: 0.390
Knob Side O-Ring: P-12
Neck Diameter: 0.820
Pilot Diameter: 1.026
Shoulder Diameter: 1.400
Wrench Flat Diameter: 1.182
Socket Part #: RKW50M
Number: JM31246
Solid Version: JM11146, JM11146HT
Alternate Part: JM31246HT
Country of Origin: USA

This knob is a replacement for the following parts:

ManufacturerPart Number
Retention Knob Supply: RK312-46
Seco: 1688
Kenn 2: 2878480
Big Kaiser: PYN50C
Command: RS6E-0204-C
MSC: 1401918
Parlec: M50TRK
For Machines (see disclaimer)*: Mazak

* Retention knobs are not interchangeable. Machines are only given as a reference, JMPP makes no guarantee this is the correct knob for your machine. Please call us at 1-800-322-7750 or email for knob identification help.

WARNING: The steel alloy used in this product contains chromium and nickel. This product can expose you to chemicals including chromium and nickel, which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to