center finder vs fingernail

[eblaschka]

Hi

I am new to this forum and finally are starting my lifelong dream to have mill and a lathe.

Just got my G619 mill...

Somewhere on the internet I saw a discussion about the pointed edge of a Starret edge finder and how to use it.

The answers were less than satisfying and of of the guys said something like
"my old fingernail method works just as good".

Now I am intrigued..

What is the fingernail technique to find the center of a hole and how do you REALLY use the pointed edge of the edge finder?

Thanks

[GeneK]

I think what they are referring to is lower the point into the hole, gently until it is touching all around. I have mine mounted in an end mill holder firmly but still able to slide if I push it down too hard.
If the hole isn't centered the joint where the tip joins the body will be off set. I 'milk' the body with my fingers first, so I feel which side the tip is off set. Re-adjust X or Y until I can't feel the seam. The finger nail test is to run your finger nail up and down across the joint to see if it is really even on all sides.

GeneK

Originally Posted by eblaschka Hi I am new to this forum and finally are starting my lifelong dream to have mill and a lathe. Just got my G619 mill... Somewhere on the internet I saw a discussion about the pointed edge of a Starret edge finder and how to use it. The answers were less than satisfying and of of the guys said something like "my old fingernail method works just as good". Now I am intrigued.. What is the fingernail technique to find the center of a hole and how do you REALLY use the pointed edge of the edge finder? Thanks

[MrWild]

I had to think a moment to what exactly was going on. You have the words right, but context wrong. The "finger nail method" has nothing to do with finding the center of a hole. We're talking Wigglers here. They wiggle. You need to center the edge finder so it works. Some people move the table so the vise or a work edge move the wildly swinging edge finder to a centered position so it isn't wiggly all over. That's kind of anal and slow.

What the guys were saying was they just use their finger nail as a hard surface for centering the edge finder. Once centered you lower the quill so the edge finder is in the hole.

Here is the beauty of the pointed end. As long as the hole lip is flat to the table, the edge finder can be lowered so that <i>any</i> part of the cone comes in contact. It's sort of a one size edge finder fits all holes. Got a 1" diameter hole? Run the pointed end down deep so the major diameter of the cone touches an edge of the hole. Got a small 1/4" hole? Only lower the tip into the hole to find the edge.

I use a dial indicator for finding the center of a hole when it has to be exact. I don't use a edge finder for holes at all. I use a dowel with a 60* point. I then lower the quill as I manually move the table around Using finesse and feel, you can feel when the dowel has gone to center. This is why I like hand wheels on my machine.