Dial Gauge: Logan, 1883

John Logan of Waltham, Massachusetts, patented this dial gauge in 1883, US 283,627. A gauging bar slides lengthwise through guides in a case with a graduated dial. A chain fixed to the bar is wound round the arbor that carries the pointer, so when the bar moves the chain unwinds and turns the pointer. The pointer's end moves much further than the bar, which makes the reading very delicate. A spring on the arbor winds the chain back and returns the bar to zero. A jaw on the case and a jaw on the bar make it a caliper; a slender rod beside the bar's other end makes it a depth gauge.

고급

Workshop process

안내

Case and dial

Make the case with the graduated dial, with tubular guide projections at opposite sides for the gauging bar.

이 단계의 재료:

눈금판이 달린 다이얼 게이지 케이스1 개

Arbor, chain and bar

Pivot the arbor carrying the pointer at the dial's centre. Pass the gauging bar through the guides and connect it to the arbor by a chain fixed to the bar and wound round the arbor.

이 단계의 재료:

지침 축과 지침1 개

측정봉1 개

가는 체인1 개

필요한 도구:

정밀 핀셋 세트

드라이버 세트

Return spring

Connect a spring between the arbor and the case so that it turns the arbor to wind the chain and draws the bar back to the zero position.

이 단계의 재료:

아버 복귀 스프링1 개

필요한 도구:

정밀 핀셋 세트

Jaws and depth rod

Fix a jaw on the case and a matching jaw on the bar; when they touch, the pointer reads zero. Fix a slender gauging rod beside the guide at the other end, in line with the bar's end at zero, for measuring depths.

이 단계의 재료: