Plug Gauge with Ball-bearing Pilot
Page 31
If you've noticed an error in this article please click here to report it so we can fix it.
New Timken Device that Expedites Production and Inspection; whilst Calling for Less Manipulative Skill in Use TOLERANCE in engineering parlance used to mean only' 1 the permissible deviation from the exact specified dimension. Tolerance of clumsy operatives did not exist. To-day matters are different. Every practicable measiire for reducing the need' for skill is adopted, so that production may be accelerated and unski:led or semi-skilled labour more widely employed,
On every hand, manufacturing processes are being made more fool-proof. Means for the elimination of the scrapping of parts through carelessness on the part of individuals have now become of great importance.
' For measuring bores, the ." go" and " not go " plug gauge, although almost universally used, is not without its faults. Among these May be named the risk of its jamming ifi the hole, probably through an error in the angle of insertion. This leads to the use of force to withdraw the gauge and consequent damage to both it and the work.
Furthermore, when finished parts are being inspected, it is not unusual for this jamming to .be mistaken for an undersize bore, with the result that a part may be rejected for an imaginary fault.
Now a new form of plug gauge has been developed which is claimed to be without the failings of the usual type. It is known as the Emmerton, and has been devised by British Timken Ltd. 'Close to the leading end of, this gauge is a ring of balls, retained in arf annular groove. They are so arranged as to be exactly flush with the cylindrical surface of the body of the gauge which is, of course, ground to size.
Free to rotate in their housing„ the balls guide the gauge into the aperture and automatically effect alignment. It is claimed that the gauge can be held lightly and inserted easily into the hole, even if the diameter of the former he', exactly that of the latter.
With this gauge in use, it is stated, the rate and accuracy of both productionsand inspection are increased, whilst working to closer tolerances is permitted. In 'addition, there are fewer rejects and the life of the gange LS considerably lengthened,