Edge Finder On Milling Machine

I have an edge finder for my milling machine it finds the edge ok but it is not exactly the edge to measure from. This tool fits in the chuck and when spun it becomes concentric when it finds the edge but the true edge it has found is the center of the edge finder tool. If I set my DRO to the setting the tool has found it is quite a few thou from the true edge, is this the way these finders work?

John

The edge finder will run concentric when touching the work piece but you then need to advance until the edge finder kicks off. That is then the edge of the edge finder.

You then need to advance the axis a further 1/2 diameter of the edge finder to set on edge of work piece

Edit for smelling

Edited By ASF on 09/07/2017 18:18:02

These usually have a nominal diameter on the part which you offer up to the job, if imperial .25 or .2 or 4 or 6 mm if metric. Usual method is when you reach the spin of point you set either your DRO or index dial to zero then move half the diameter to get the true edge position. Then reset to zero and you are ready to index.

Michael

As you say you have a DRO therefore when the finder kicks set the axis to + or - half the dia of the edge finder depending what side of the work you are touching off of. Saves having to zero twice.

Thanks for your replies, I have been subtracting half the diameter just thought I was missing something.

John

Sometimes I put some bearing blue on the edge finder. You can see when it has a full contact just before it kicks off. My new one has a 10mm ceramic disc instead of the 6mm steel. The steel one is from like 1990 or so. Still works fine. I like the ceramic as it is anti magnetic. I found that if the part is slightly magnetic, or if the disc has got magnetised over the years, it reads incorrectly. So I run them over a demagnetiser periodically.

Neil