Precision Devices, Inc.

Centerline Ball Arbors and Chucks

Centerline Ball Arbors and Chucks

Precision Devices, Inc. Centerline Ball Arbors

Precision Devices, Inc. Ball Arbors are used primarily to position parts for inspection of runout, concentricity, squareness and parallelism. Parts may be straight or tapered, plain or serrated, full circumference or segmented (diameter range1/4" to 16"). Ball arbors are often used to solve difficult gauging problems, such as center distance gauging, true hole positioning and checking the requirements of geometric tolerancing.

PDI Centerline Ball Arbor Two Row Ball Arbor with Runout Master

Precision Devices, Inc. Centerline Ball Chucks

PDI Ball ChucksPDI Ball Chucks employ the same exclusive ball-ring principle as the ball arbors, and are used to locate O.D.s from .156" to 16". As with our ball arbors, ball chucks are used primarily to inspect parts for runout, concentricity, squareness and parallelism.


Custom Built

PDI ball arbors and chucks can be manufactured with a single row or multiple rows of ultra-precision steel balls. Each row of balls moves independently of the other, accurately establishing the true axis of the work piece.

The ball tracks may be spaced together or apart. The spacing, as well as the diameter and quantity of the balls used in each ball track, is selected to achieve maximum accuracy and repeatability. Repeatability of .000050" can be realized.

PDI Ball Arbors and Chucks are all custom designed and built to each customer's application. In addition, PDI has the capability to provide complete inspection packages, including arbors/chucks and all associated fixturing to meet your exact gauging requirements.

The Ball-Ring Principle

Centerline

The key to many of the features of PDI Arbors and Chucks lies in the circle of precision balls that contact the part. Seated in an expandable raceway, the balls firmly contact the part, establish and maintain its true axis, and still allow it to rotate freely. The workpiece I.D. or O.D. is always centered, regardless of slight variations in diameter, roundness or taper.

PDI Ball Arbors and Chucks are virtually indestructible. The precision balls are made of hardened steel and the faces that form the V-grooves are hardened, ground and lapped. Ball wear is compensated for by self-rounding. These devices will do their jobs and maintain their accuracy through many years of constant use.

Advantages

  • Accurately establishes axis I.D. or O.D. up to .000050"
  • Does not distort part
  • Provides means of measuring runout, concentricty, squareness or parallelism
  • Wide range of expansion, with no loss of accuracy
  • Free rotation of part on arbor
  • Unaffected by taper or out-of-round
  • Will hold on interrupted surfaces
  • Self-actuating
  • Easily adapted to existing gages
  • Antifriction feature contibutes to long wear life

Applications

For piece parts with same locating diameter but varying parts lengths, multiple row arbor/chucks can be used, as in the arbor at left; Certain processes may require locating on diameters of different size. The arbor/chuck will determine the centerline of the part based upon the two different locating planes
For piece parts with same locating diameter but varying parts lengths, multiple row arbor/chucks can be used, as in the arbor at left; Certain processes may require locating on diameters of different size. The arbor/chuck will determine the centerline of the part based upon the two different locating planes.

Ball arbor indicator sweep gage for measuring counterbore runout
Ball arbor indicator sweep gage for measuring counterbore runout.

Flange runout and thickness gage with a single rown ball arbor
Flange runout and thickness gage with a single rown ball arbor.

Establishing the centerline with a two row ball chuck to measure I.D. to O.D. concentricity
Establishing the centerline with a two row ball chuck to measure I.D. to O.D. concentricity.

I.D. runout gage using single row ball arbor and datum face for locating
I.D. runout gage using single row ball arbor and datum face for locating.

Multiple concentricity and squareness measurements from a single fixturing
Multiple concentricity and squareness measurements from a single fixturing.

Ball chuck mounted on a sine plate for accurate angular adjustment
Ball chuck mounted on a sine plate for accurate angular adjustment.

Two row ball arbor with nut for measuring gear characteristics
Two row ball arbor with nut for measuring gear characteristics.

Centerline axis established by two row ball arbor on different parameters
Centerline axis established by two row ball arbor on different parameters.

Ball arbors with wobble washers to clamp part and not influence part position
Ball arbors with wobble washers to clamp part and not influence part position.

Centerline of an engine crankshaft bore was established through the use of a ball arbor. The face squareness attachment at left, when placed on the arbor, checked the squareness of critical surfaces with respect to the crankshaft bore
The centerline of an engine crankshaft bore was established through the use of a ball arbor. The face squareness attachment at left, when placed on the arbor, checked the squareness of critical surfaces with respect to the crankshaft bore.

This two-piece interlocking arbor locates in the tapered inboard and outboard cups of a disc brake
This two-piece interlocking arbor locates in the tapered inboard and outboard cups of a disc brake.

The centerline of tapered parts can be established through the use of our ball arbors/chucks. The ball arbors illustrated were designed to locate in the bore of disc brake flanges
The centerline of tapered parts can be established through the use of our ball arbors/chucks. The ball arbors illustrated were designed to locate in the bore of disc brake flanges.