Bo’sun
The quill clamp I use with the dial indicator is from a commercial holder I purchased. When trying to use it I found it was next to useless.
It clamped to the quill at three points, two raised parts at 120 degrees apart and a plastic tipped screw opposite them. The two raised parts were not flat but were as cast and the screw had a soft plastic tip.
The result was that no matter much the screw was was tightened the whole assembly would wiggle.
Also when the dial indicator was attached to the arms it was a real fiddle to get it in a good position and even when it was, the whole assembly was so flexible it couldn’t be relied on to give an accurate reading.
So I got rid of all the pieces except the cast quill clamp and made some modifications to it.
I replaced the plastic tip on the screw with one made of aluminum, and using a 1″ end mill cleaned up the two cast quill contact points to make them flat (well semi circular) and at 90 degrees to the face of the clamp.
I also drilled an extra hole in the body of the clamp to mount a 1/2″ dia steel post that the dial indicator screws to.
The result is a holder that is now totally rigid when clamped to the spindle.
Hope the pictures make this all clear. The first is the original unit (but with the mods to to clamp body showing) and the other two are the modified clamp.
John


