Product Description

BXT Series Bar Extensions

Allows use of sphere-fit routines for hard-to-target points

The BXT Series Bar Extensions are used in conjunction with the Tooling Ball Adapters (TBA) or Bar Points (BP) on one end, and various SMR holders having a mating shank (1/4″ or 6mm) on the other. This type of assembly (see photo at bottom of page) is often used to locate and specify points using sphere-fit routines*. Use our BP point with the BXT bars when targeting scribe lines or other points of interest on surfaces or contours. Then replace the BP with our TBA adapter to target the centers of tooling balls. Or, use this assembly and the sphere-fit procedure with our Construction Tooling Ball (TB) targeting accessory. This technique is especially useful when the desired targets are obscured from view. It allows you to avoid making additional tracker moves and subsequent rebundles, thereby saving time and potential error buildup. These adapters make more efficient use of your laser tracker equipment while maintaining the accuracy needed for most tasks.
Model Length “A” Diameter “D”
BXT-5 5.0000″ 0.250″
BXT-10 10.0000″ 0.250″
BXT-125MM 125 mm 6 mm
BXT-250MM 250 mm 6 mm
English or metric bars are available, having, respectively, 1/4″ or 6mm shanks and matching 1/4″ or 6mm precision bores on the opposite end of the bar. All shanks are drilled and tapped with a 6-32 internal thread. The shank then mates with the connecting screw on the inside of a TBA or BP tip, again assuming that English and metric tips are matched with English and metric bars, respectively. Both tips are seen in the photo at right. The precision bore on the opposite end will accept SMR nests which have a matching shank diameter (1/4″ or 6mm), such as 1.5TH-1-.25 or 1.5TH-25MM-6MM. These accessories are held in place with a radially-mounted, nylon-tipped setscrew.
*A “sphere fit rod” assembly (shown left) may be constructed from a BXT bar, an SMR adapter, and a BP Bar Point or a TBA Tooling Ball Adapter. It is used to measure a number of points which are all a given distance away from one particular point of interest, making that point of interest the center of an arbitrary sphere. Then, a sphere-fit routine is commonly used to calculate that center point.

May Be Used With

BP Bar Point
TBA Tooling Ball Adapter
1.5TH-x-.25, 0.875TH-x-.25, or 0.5TH-x-.25 (may be used with BXT-5 and BXT-10)
1.5TH-x-6MM, 0.875TH-x-6MM, or 0.5TH-x-6MM (may be used with BXT-125 and BXT-250)


Tolerance, precision bore:
+0.0005″, −0.0000″ (+0.013, -0.000mm)
Tolerance, shank:
+0.0000″, −0.0005″ (+0.000mm, −0.013mm)
Tolerance, length: ±0.0005″ (±0.013mm)
Material: Stainless steel
Hardness: HRC 42-45