American Precision Gauge, LLC

American Precision Gauge, LLC established to create, design and build Linear
Digital Measuring Devices (LDMD) or Long Travel Calipers.

The LDMD was created as a solution to one of those situations where no good alternative existed. For years providers of shafting, piping, tubing, wood products and other long length components had to rely on simple tape measures for cut to length operations and inspection and set up. Even in today’s machine shop environments where 24” to 60” parts are commonplace there remains a need to inspect and verify on the floor and the typical caliper cannot meet the needs and few options were available, until now.

American Precision Gauge ( has created and built several versions of the LDMD including the ultra-precise linear scale with DRO, the LDMD 2 specifically for round type products up to 4″ in diameter with a separate DRO. These devices proved to be accurate and reliable with travel lengths to 120″. The short comings were cost, the need to have 110 V ac nearby and trans-portability. Each of the previous LDMD’s needed to be fully supported and usually meant mounting to a rolling table with a precision top making the units transportable but came with a cost premium.

LDMD series Old

The New LDMD 3.0 answers many of those cost and trans-portability issues. Made from a light-weight custom designed aluminum base  precisely machined to incorporate two ultra-precision ground aluminum shafts with ceramic coating making the LDMD 3.0 light weight and precise.

The carriage which houses the LCD digital display and read head slides effortlessly along the measurable travel length on preloaded linear bearings matched to the coated shafts for long life and consistent straight-line travel with negligible pitch, roll or yaw issues.

LDMD carriage w/copy

Each LDMD display is battery operated using 2 AAA replaceable batteries meaning no cords to tangle or wires to interfere. Battery life offers a three-year life with standard usage and is user replaceable with only a simple screwdriver.

LDMD carriage w/copy 2

The display offers a fully programmable LCD single line data with Inch or metric output capable of 4 decimal place resolution. Unit is operated in either absolute or incremental modes, programmable offsets, reference set points, sleep timer and selectable direction of travel feature. Any movement of the carriage wakens the display without position loss. 

The end plate, carriage and contact paddles are configured in such a way as to allow them to be removed and replaced with custom end of arm tooling to suit your needs or reversed to allow the LDMD to be configured in a way to suit your needs.    

The LDMD 3.0 does not have error compensation, however, each unit is meticulously tested via a laser interferometer traceable to NIST standards to ensure every unit that leaves our shop operates within the accuracy quoted. That accuracy is to be within .005″ of the nominal anywhere along its full length of travel

and repeatable within .001”. With each unit we include documentation as to how your unit performed during this testing and we provide a graph showing exactly where the error does occur and how the user can mathematically remove the error for even more precise results.

The net result is, the LDMD 3.0 is accurate, repeatable, light enough to carry around the shop, easy to use right out of the box or can be easily adapted to your needs either through programming and/or by re-configuring end of arm tooling.

If carrying the LDMD 3.0 is not a preference or if longer lengths are required, offers fixed tables and rolling gauging stands to fit your application. 

rolling and fixed tables

Want to learn more about American Precision Gauge, LLC and our line of Linear Digital Measuring Devices (LDMD)? 

Call us at 714-340-0580