A-512 2-Axis Target 10×10 PSD for Self-Centering Bore Adapters

A-512 2-Axis Target 10×10 PSD for Self-Centering Bore Adapters


The A-512 2-Axis Bore Target is a general-purpose, 2-axis target comprised of a target and an insertion pole or handle. It is used with our A-514A (3.75 in. – 6.75 in.), A-514B (6.5 in. – 17.5 in) or A-514C (17 in. – 40 in.) Adjustable Self-Centering Bore Adapters to measure the alignment of bores.  The target/adapter automatically centers itself in any bore size that is +/- .030 in. (+/- 0.8 mm) from the adapter bore diameter.

The self-centering concept works by carefully centering the target PSD sensor axially between the feet. This puts the target cell on the pivot point of the adapter and legs and allows it to vary by up to 45º without affecting the center. One pair of adapter legs are offset from the other, so when it is inserted in the bore (by pulling on the cord and tipping it forward) and the cord is released and the weight of the pole or handle “jams” the target/adapter into the bore, centering itself.

The A-514A,B,C Adapters require the use of the A-514GS or A-514GL Leg-Setting Gage to set the legs to the nominal bore ID.  Setting the legs to the exact diameter is no critical since the adapters can handle a diameter range of +/- 0.030 in. (+/- 0.8 mm).

The accuracy of the measurement of the A-512 with the A-514 adapters is .00075 in. (0.019 mm) with repeatability to .0002 in. (0.005 mm) in well machined bores.


  • Any bore application with minimum of 3.75 in. (92.3 mm) diameter
  • Boring-bar bearing supports
  • Compressor bores – alignment both concentricity and angular
  • Cylinder straightness up to 25 feet (7.6 m)
  • Extruders – single or twin barrels – up to 25 feet (7.6 m)- alignment and straightness checks
  • Engine block crankcase bores – alignment both concentricity and angular


  • Self-centering, 2-axis target accurate to .00075 in. (0.019 mm) with a resolution of up to .00002 in.  (0.0005 mm) with R-358 Computer Interface, or .0001 in. (0.001 mm) with R-1307 Readout
  • Measures bore straightness and alignment.
  • Tips on adapter feet use hardened carbide steel balls that rarely wear out.
  • Target with adapters can handle diameter variations up to of +/- .030 in. (0.8 mm).
  • Rugged, portable and very lightweight.
  • Uses the following bore adapters:
  • A-514A for bores from 3.75 in. (95 mm) to 6.75 in. (172 mm)
  • A-514B for bore diameters from 6.50 in. (165 mm) to 17.5 in. (445 mm)
  • A-514C for bore diameters from 17 in. (431.8 mm) to 40 in. (1 M)


14 oz (392 g)
Material Hardness:
440C stainless Rockwell RC55-60
Target Concentricity:
.0003 in. (0.0075 mm) TIR to 1.1248 in. (31.745 mm) OD of target housing
Target Resolution:
.0001 in. (0.001 mm) with Bore9 Software and the R-1307 or .00001 in.  (0.00025 mm) with R-358 Computer Interface
Target Measuring Range:
+/- .080 in. (2.0 mm) with 5 mm diameter laser beam
Within 1-5% (See Target Cell Accuracy for details)
Cord Dimensions:
Target to connector 10 ft. (3 M)
Mounting Dimensions:
1.2498 in. O.D. (31.745 mm)