Gage Provides Reference Setting for a Range of Applications
The L.S. Starrett Co. introduces its Digi-Check height masters with electronic digital readout. The Digi-Check No. 258 series combines the Starrett-Webber gage blocks with a micrometer head and digital readout display. The device provides a reference setting for checking bore gages, inside micrometers, end measuring rods and other gages, and height measurement of parts.
The device features a large digital display, providing a readout of 0.0001" (0.001 mm). In addition, a graduated satin chrome finished precision micrometer head with speeder knob for fast positioning provides graduation readings of 0.0001" (0.002 mm). Both the micrometer head and digital readout are in line with the operator’s vision. The gage is housed within a flanged frame and base featuring three-point hardened, ground and lapped bearing pads, contributing to an accuracy of ±0.0002" (±0.005 mm). Gage blocks are assembled in a free-standing system isolated from the frame, enabling the blocks to conform to the workpiece temperature. According to the company, accuracy is enhanced via a one-piece micrometer spindle with hardened and stabilized measuring threads.
Both over and under heights can be checked from the gage blocks in a single setting With reference surfaces on the top and bottom of each block, adjacent blocks are positioned in the same plane. Readings are also taken from either left, center or right of the gage block column. The column design enables wringing a 1" block between two blocks in the column.The gages are offered in three ranges: 0.100" to 12.100", 0.100" to 18.100" or 0.100" to 24.100". Metric models are also offered in three ranges: 2 to 302 mm, 2 to 452 mm or 2 to 602 mm. Gages are set in wood cases. Accessories such as the company’s reverse reading blocks and riser blocks are also available.
While countersunk and chamfered holes are similar in appearance, functionally they are quite different. Consequently, different gages exist to serve these different functional requirements.
Virtually every machine tool builder lists, as part of a machine's specification, accuracy and repeatability figures. What's generally not given is the method used to arrive at the figures. Though these methods are defined in linear positioning standards, not all builders use the same standards.
Different instruments (and different operators) are prone to different errors.