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Pratt Burnerd 3-Jaw Constant Grip Power Chucks

MADE IN USA

Constant Grip High Speed Standard and King Bore Thru-Hole Power Chucks Sizes 6″ Thru 24″

  • MADE IN USA
  • One Year Warranty
  • High RPM – up to 6000
  • Constant Grip, internally counter-balanced design that reduces grip loss from centrifugal force of the jaws at high RPM.
  • Easy Retrofit on most all existing NC and CNC lathes utilizing the same drawtube and actuating cylinder including Japanese types.
  • Accurate – repeatability of ± .0005″
  • 3-Point Adjusting Feature in the chuck body permits indicating in to zero. Increase Soft Jaw Life by using adjustment feature. Reduce or eliminate re-boring of Soft Jaws.
  • Doubles as collet chuck as master jaws have keyed radius in front that accept standard W & S collet pads. Eliminate time wasted on switching over to collet chuck.
  • Large Thru-Hole Capacity
  • Utilize existing top tooling by selecting style of master jaws from 1.5 x 60, 1/16″ x 90, Am. Std. Acme, Am. Std Tongue & Groove and Square Serrationsor substitute mono block jaws. Sets can be mixed styles.
  • Also available in 2-jaw style.
  • Chuck sizes available 6″, 8″, 10″, 12″, 15″,18″, 20″ and 24″ diameters.
Chuck SizeMount
(D)Direct (I)Indirect		RPMModel No.*Jaw StrokeSleeve StrokeThru HoleCollet Pad Bar CapacityTooling Hole SizeOperating Force lbs/fGrip Force lbs/fWt (lbs)
6.5"A2-4(I)60009151-217__.140".630"1.65"1.5"5/16" UNC3600990031
6.5"A2-5(D)60009151-317__.140".630"1.65"1.5"5/16" UNC3600990031
6.5"A2-6(I)60009151-417__.140".630"1.65"1.5"5/16" UNC3600990031
8.25"A2-5(I)55009151-321__.140".630"2.05"2.0"5/16" UNC62001500053
8.25"A2-6(D)55009151-421__.140Z.630"2.05"2.0"5/16" UNC62001500053
8.25"A2-8(I)55009151-521__.140".630"2.05"2.0"5/16" UNC62001500053
10.0"A2-6(I)50009151-426__.160".730"2.56"2.5"3/8" UNC72001980082
10.0"A2-8(D)50009151-526__.160".730"2.56"2.5"3/8" UNC72001980082
12.0"A2-8(I)42009151-531__.160".730"3.54"3.0"3/8" UNC990027000150
12.0"A2-11(D)42009151-631__.160".730"3.54"3.0"3/8" UNC990027000150
15.0"A2-8(I)30009151-538__.200".790"4.92"4.5"3/8" UNC1350031500280
15.0"A2-11(D)30009151-638__.200".790"4.92"4.5"3/8" UNC1350031500280
18.0"A2-8(I)25009151-546__.236".984"5.59"5.5"1/2" UNC1550038250375
18.0"A2-11(I)25009151-646__.236".984"5.59"5.5"1/2" UNC1550038250375
20.0"A2-11(I)25009151-650__.236".984"5.59"5.5"1/2" UNC1550038250550
24.0"A2-11(I)18009151-660__.315".984"6.299"6.25"1/2" UNC2070038250760
24.0"A2-15(D)18009151-760__.315".984"6.299"6.25"1/2" UNC2070038250760
King Bore Chucks
7.0"A2-5(D)70009161-318__.140".630"2.20"2.0"5/16" UNC45001300037
8.25"A2-6(D)55009161-421__.140".630"2.59"2.5"5/16" UNC54001500053
10.43"A2-6(I)50009161-426__.160".730"3.03"3.0"3/8" UNC72001980082
10.43"A2-8(D)50009161-526__.160".730"3.03"3.0"3/8" UNC72001980082
12.40"A2-8(I)42009161-531__.160".730"4.05"4.0"3/8" UNC990027000183
12.40"A2-8(D)42009161-531__.160".730"4.05"4.0"3/8" UNC990027000183
Insert last two digits for Master Jaw type...Example 9151-21723...Indicates 1.5mm x 60°: Master Jaw Required
Use 23 for 1.5mm x 60° Japanese type.** Use 07 for Am. Std Tongue & Groove. Use 10 for 1/16 X 90° Serrations.***
Use 26 for Acme Serration. Use 27 for Square Serration.
NOTE: 18, 20 & 24 dia. chucks require separate collet pad master jaws: 18-#8130-46696, 20-#8130-50696 & 24-#8130-61696.
**3mm on 20 and 24 dia. chucks ***3/32 x 90° on 20 and 24 chucks
Dimensional and Performance Data (in inch)
E
Chuck SizeABCDFMaxMin
6-A46.54.6854.8033.250.7872.1261.339
6-A56.54.8424.964.1250.7872.1261.339
6-A66.55.0785.1965.250.7872.1261.339
8-A58.255.1195.2754.12512.6371.733
8-A68.255.3545.515.2512.6371.733
8-A88.255.7055.8626.7512.6371.733
10-A6105.5115.6695.251.1813.2682.087
10-A8105.9056.0636.751.1813.2682.087
12-A8126.6146.7716.751.1814.2912.362
12-A11126.6146.7719.251.1814.2912.362
15-A8156.9297.0866.751.69353.228
15-A11156.9297.0869.251.69353.228
18-A8187.727.786.751.6936.7724.527
18-A11187.727.789.251.6936.7724.527
20-A1119.77.3627.4999.252.3628.095.059
24-A11247.567.729.252.36210.095.77
24-A15247.567.72132.36210.095.77
Dimensional and Performance Data (in inch)
L
Chuck SizeGHJKMinMaxSW
6-A4M10x25(6)M10x255⁄16 UNFx1⁄22.990.941.570.4751.22
6-A5M10x130(3)M10x255⁄16 UNFx1⁄22.991.11.730.4751.22
6-A6M12x30(6)M10x255⁄16 UNFx1⁄22.991.52.130.4751.22
8-A5M10x30(6)M12x353⁄8 UNFx3⁄43.940.981.610.5511.57
8-A6M12x130(3)M12x353⁄8 UNFx3⁄43.941.191.810.5511.57
8-A8M16x30(6)M12x353⁄8 UNFx3⁄43.942.022.650.5511.57
10-A6M12x35(6)M12x351⁄2 UNFx3⁄44.531.021.750.631.57
10-A8M16x150(3)M12x351⁄2 UNFx3⁄44.531.412.150.631.57
12-A8M16x40(6)M14x451⁄2 UNFx3⁄45.711.32.030.711.81
12-A11M20x160(3)M14x451⁄2 UNFx3⁄45.711.32.030.711.81
15-A8M16x35(6)M20x551⁄2 UNFx3⁄4473/7891.382.160.8662.36
15-A11M20x180(6)M20x551⁄2 UNFx3⁄4473/7891.382.360.8662.36
18-A8M16x40(6)M20x551⁄2 UNFx3⁄4433/6301.382.360.9842.36
18-A11M20x35(6)M20x551⁄2 UNFx3⁄4433/6301.382.360.9842.36
20-A11M20x45(6)M20x351⁄2 UNFx3⁄4705/9941.382360.9842.36
24-A11M20x45(6)M20x351⁄2 UNFx3⁄4***1.572.560.9842.36
24-A157/8-9x8(6)M20x351⁄2 UNFx3⁄4***1.572.560.9842.36
(T) Draw Tube Thread Blank
1. Dimensions listed are with 1.5 x 60° master jaws. Some dimensions will vary using other Master Jaw types such as Acme, 1/16" x 90° or Am. Std. Tongue & Groove.
2. Chuck is at mid stroke with master jaws flush with the body O.D.
3. UNC mounting bolts available upon request.
4. Standard master jaw serration for 20 and 24 inch chucks are 3mm x 60°.
***9.45"/13"/16.53"/20.08"