Runout Adjustable RA Holder

Runout Adjustable RA Holders are milling and collet chucks that compensate for the decreased runout accuracy of a machine tool spindle. Runout accuracy of a machine tool spindle can be decreased after extended use. Long drilling or reaming operations on such machines leads to variations in precision, shortened tool life, etc. The RA Holder is an effective countermeasure to these problems.

Runout Adjustable RA Holder

Using the RA Holder Provides the Following Benefits

  • Uniform hole diameter

  • Improves surface roughness

  • Extends tool life

*** Program based on BBT taper but other tapers available upon request

Two Types of Runout Adjustable RA Holders

BIG-PLUS® New Hi-Power Milling Chuck Type


Clamping Range Dia.: 20mm - 32mm
Gauge Length: 4.724" - 5.709"

BIG-PLUS® New Baby Chuck Type


Clamping Range Dia.: 2.5mm - 20mm
Gauge Length: 3.543" - 5.906"
Note: Other tapers available upon request*

Simple Design & Easy Adjustment

1. Rotate the runout adjustment screw and align the triangular mark with the peak runout

2. Fix the runout adjustment ring by tightening (3) lock bolts

3. Adjust runout by rotating the runout adjustment screw