Bore clock

[olderdan]

I made this about 40 years go from a Model Engineer article before digital calipers became so affordable. Overall it works very well, it has a range of 3/8 to 2 inches. The slightly awkward part is transferring the reference to a micrometer it being a bit of a juggle to hold both items at once, the answer of course is to use a micrometer stand (my next project). Over the years I have gained some bore mikes to make this a bit redundant. Personally I find telescopic bore gauges just as good to use but this seemed like a good idea at the time like so many things.

[mklotz]

Having made a similar device...

Simplifying the measurement of bores

I'm interested in how yours operates. Am I correct in assuming that the small knurled screw pivots the movable measuring arm, said movement recorded on the dial indicator (here in the colonies "clocks" tell time) ? Then the micrometer is applied to the measuring points and adjusted until the DI reading is duplicated at which point the micrometer reflects the bore diameter ?

[DIYer]

Thanks olderdan! We've added your Bore Clock to our Measuring and Marking category,
as well as to your builder page: olderdan's Homemade Tools. Your receipt:

Bore Clock by olderdan

tags: dial indicator