Specification - Back Plate Selection Guide

Selecting the chuck mounting:


  • For short taper spindle noses Type A & D, measure the pilot diameter and length (B), bolt circle diameter (dimensions F1 & F2) and diameter of the holes (dimensions E1 & E2)
  • In the case of A type mount, check the number of bolt circles (A2 mount or A1 mount).
  • All chucks with A1 mounting chuck can only be mounted on A1 spindle head.
  • All chucks with A2 mounting can be mounted on the A1 or A2 spindle nose.
  • For the Camlock spindle type D1, check the number of holes and stud diameter.
  • For the long taper spindle noses Type L, check pilot diameter, length and thread size (A & B).
  • For the threaded spindle noses, check the thread diameter, number of threads per inch and length (dimensions B & D), plus overall length (dimension F)

Camlock Spindle Tpye D1


Spindle Nose A F B C max. E No. of Holes Camlock Stud Dia
D1-3 3.622" 2.7820" 2.1250"+0.00025" 0.4375" 0.5937" 3 9/16"
D1-4 4.606 3.2500 2.5005+0.0005 0.4375 0.6562 3 5/8
D1-5 5.748 4.1250 3.2505+0.0005 0.5000 0.8750 6 3/4
D1-6 7.126 5.2500 4.1880+0.0005 0.5625 1.000 6 7/8
D1-8 8.858 6.7500 5.50075+0.0005 0.6250 1.125 6 1

Threaded Spindle


Spindle Nose A B F1 D E
1"-10" UNS-2B 1.015" 1.500" 0.4375" 1.000"
1"-1/2" -8" UNS-2B 1.515" 1.500" 0.4375" 1.000"
2-3/16"-10" UNS-2B 2.2025" 1.750" 0.5625" 1.125"
2-1/4"-8" UNS-2B 2.260" 1.750" 0.5625" 1.125"
2-3/16"-6" UNS-2B 2.2025" 1.750" 0.5625" 1.125"
2-3/4"-8" UNS-2B 2.760" 2.0625" 0.6875" 1.3125"

Spindle Type A1 & A2

  • Type A1 has tapped holes on both inner and outer bolt circles.
  • Type A2 does not have holes in the inner bolt circles.
Spindle Nose F1 F2 B C max. Thread E1=E2 UNC-3B
A-4 3.2500" - 2.5005"+0.0005" 0.4375" 7/16-14"
A-5 4.1250" 2.4374 3.2505"+0.0005" 0.5625" 7/16-14"
A-6 5.2500" 3.2500 4.1880"+0.0005" 0.6250" 1/2-13"
A-8 6.7500" 4.3750 5.50075"+0.0005" 0.6875" 5/8-11"

Long Taper Key Drive, Spindle Type L


Spindle Nose Thread B C A Key
L00 3-3/4" - 6" 2 2.75" 3/8 x 3/8 x 1-1/2"
L0 4-1/2" - 6" 2-3/8 3.250" 3/8 x 3/8 x 1-3/4"
L1 6" - 6" 2-7/8 4.125" 5/8 x 5/8 x 2-3/8"
L2 7-3/4" - 5" 3-3/8 5.250" 3/4 x 3/4 x 2-7/8"
L3 10-3/8" - 4" 3-7/8 6.500" 1 x 1 x 3-1/4"