Edge & Center Finder

[jhanko]

Thanks to this excellent video, I learned how to use an edge finder. I can't find any information on how to find center using the cone end. Any insight? Thanks,

Jeff

 

[gadget_lover]

I think that's for indicating to small holes where the body of the edge finder is too large to fit.

I use a wiggler for that since it is less math and I don;t have to worry about backlash screwing it up.

Daniel

 

[precisionworks]

how to find center using the cone end

As Daniel said, small holes are one use, and center punch marks are another. The pointy end is much more delicate than the straight end, so you want to use the lightest touch possible. Run the machine under 1000 rpm (per Starrett), use your thumbnail to align the cone to the body, lower the cone into the hole or punch mark - watch where the cone moves & adjust X & Y to get closer to center. Align the cone again & repeat until the cone does not move when the hole or punch mark is touched.

There is a tiny spring that secures both the cone end & the straight end to the body of the center finder. The tool is designed for radial contact, not axial pressure, which is why the cone is so delicate. You can get pretty close, probably within +/- .010 or less, but it isn't the best method if great precision is needed.

It's easier, faster, and far more accurate to mount a dial test incicator to the spindle.

With the machine in neutral or the belts loose, turn the spindle & watch the indicator. Adjust X & Y for zero runout. This will allow centering well under .001

A handy tool for some situations is a Blake Co-Ax indicator, which allows centering with the spindle running at low rpm.

http://www.blakemanufacturing.com/pages/aboutus.html

Sort of pricey, but always a few on eBay. A real lifesaver on deep hole centering where the dial test indicator will not reach.