19-04-2014, 04:28 PM
Dial Indicator
Dial Indicator.pptx (Size: 225.14 KB / Downloads: 11)
Introduction
A measuring instrument with a contact point attached to a spindle and gears that moves a pointer on the dial. Dial indicators have graduations that are available for reading different measurement values.
A plunger moves in and out from the body of the indicator and rotates the measuring needle on a dial face. Dial indicators usually have either a 1" or 2" range and are calibrated in increments of .001". A smaller dial reads each revolution of the larger dial in increments of 0.100".
The outer bezel rotates and turns the numeric scale with it so that you can set the indicator to zero at any plunger position. Most D/Is have two little movable markers on the outside of the dial face that can be used as reference points.
Principle
If the bolt is off-center, the DI plunger will move in and out as the chuck rotates.
When the bolt is properly centered there will be little or no movement of the plunger and the needle of the DI will move only .001 or less.
Uses
Centering cylindrical stock in 4 jaw chuck
Determining accuracy of lathe or mill alignment.
Determining run out of lathe spindle or chucks
Aligning stock for milling
Monitoring depth of drilled holes
Monitoring vertical movement of milling head
Determining if edges of a rectangular work piece are parallel