Using a bar gauge lets you directly transfer and compare dimensions without conversion to numbers, reducing the chance of transcription errors. You can even use it to quickly test an assembly for squareness by checking that the diagonals are equal.
The base unit consists of two 152mm steel rods fixed to aluminum clamp heads. The rods have threaded end holes that accept interchangeable brass tips or extension rods.
Three styles of tips are included: ball tips for inside measurements (the rounded ends avoid marring softwood), pointed tips for inside corner measurements, and 20.5mm diameter mushroom-shaped tips to hook over edges for outside measurements. The distance between the ends of the round or pointed tips is equal to the distance between the inside faces of the mushroom-shaped tips, letting you convert an inside measurement to an outside measurement just by switching tips.
The clamp heads have large thumbscrews and slide easily for quick adjustment. The base unit adjusts from 190 – 305mm. Two pairs of extension rods are included, 102mm and 305mm, allowing a span up to 1115mm. For greater reach, additional 305mm extension rods are available.