View Full Version : Hole center-finder ?? what to use

09-01-2005, 12:23 PM
I made a hole finder with a dial indicator like John S had made. I wasn't feeling too well that day and got it mostly made, then I screwed it up and throwed it out the door at the "woods" behind my shop. (a good place to find things, several motorcycle fenders have hit the woods)

My ideal, and I need someone else to build it to try out the ideal. A chinese $15 caliper turned sideways at the bottom of a arbor. You insert it into a hole and spin the quill by hand. Get two measurements 90 degrees out and recalculate center. One blade will have to be "center" of the quill. Other blade on the caliper would be radius.

If you want to get fancy? I am thinking of a 4" x 1/2 air cylinder here to open caliper and a rs232 comm link to tell my computer what it sees. Furthermore? I can think of two ways to index quill 90 degrees at a time.

Will this work? I have a spring loaded 1/4 rod with a step mandrel I cut on the lathe, you lower the z till it fits the hole at the right step size. This gets close, but I have screwed up a few things by being close and not dead nuts on.

David Cofer, Of:
Tunnel Hill, North Georgia

[This message has been edited by ibewgypsie (edited 09-01-2005).]

Rusty Wrench
09-01-2005, 03:12 PM
I have a co/ax center finder I purchased from J&L. It works fine. It is not a Blake but it gets the job done quickly. Before I bought the co/ax, I used my wiggler with the ball. I hope this is wil help out.

Russ Hobgood

09-01-2005, 08:00 PM
I think you would need to weld or glue a small diamter ball to the jaw face, otherwise it would grab and scratch at the part while you were trying to indicate. It seems kinda like an overkill if you ask me(basically all that rs232 stuff confuses me lol), but it would be interesting to see it done. How bout making a home made digitizer, if you digitized the hole you would know where the exact center is, and to top it off a digitizer would come in handy for more than just finding hole centers.