Dial calipers are for making somewhat educated guesses. They are far too susceptible to making huge mistakes from applying too much or too little pressure to the handwheel, or getting the jaws misaligned while taking measurements. Even an inexpensive set of 0-6 inch micrometers from Ebay is head and shoulders ahead of a good digital caliper. I've got both- - -a 6" Starrett digital for when I want to make a pretty accurate guess, and a set of micrometers with a Vernier scale for when I want to slice a strand of hair into several equal increments. I've also got a set of inside mikes, and at least half a dozen different types of dial indicators. I use them all, regularly, and trying to make one do the job of another is a lost cause. I'm accustomed to splitting thousandths when I'm boring and honing cylinders for new pistons, and working to the same accuracy when reconditioning conacring rods. The oil clearance on a 2" diameter solid steel wrist pin in the connecting rod bushing for an 855 cubic inch Cummins Diesel is .0004"- - - -that's a strand of hair split into three equal slices. Engine machining is no place for "Measure it with a micrometer- - - -mark it with chalk- - - -cut it with an axe!"
Jerry
