How to use a center finder

[prasad]

Prasad, a more slender rod would be better. You want it to flex as the out-of-center punch mark moves around a circular path as you rotate the chuck. I would use nothing larger than around 3/16". Then, use your indicator up close and personal to the part you are dialing in.

If you have a good running chuck, or a collet (even better), you can grind a point on your centering rod. Just mimic the angle of a live center as you would use in a tailstock. But it doesn't have to be exact. Just as long as it will seat well enough in your punch mark.

Thank you Tony, I like this idea better than using the feeling center finder with a finger. I will order 1/8" drill rod on McMaster and it is very affordable. Yes, I do have a decent 4-jaw chuck and I will use my new Dremel tool holder for grinding the cone end.

Thanks again,
Prasad
Wynnewood PA

 

[visenfile]

Noob here understands some of this discussion...but. Is this discussion restricted to lathe? I do not have one but am familiar with punches and drilling vertically. So is the lathe so rigid that e.g., after determining that the punch mark is off , the lathe driller can drill to the desired point adjacent to the punch mark? With my lowly drill press and mill-drill I am familiar with the tendency of a drill to walk into the mislocated punch mark. I am fairly good at moving the punch mark to compensate for mislocation of original punch mark. Hope I have not spoken off topic.

 

[EmilioG]

Do you refer to a conical center finder on one end of an edge finder? Everyone seems to use theirs differently for centering up punch marks and small holes.

Tony Wells,the administrator,and a machine shop owner, gets his punch mark close enough that he can stick the center point into it. Then,he moves the X and Y axis until his fingernail doesn't catch on the mating edges of the center finder at positions 90º apart.

Then,he considers the punch mark to be accurately located on center with the spindle.

I get mine centered until I can measure across the mating joint with a micrometer at 2 places 90º apart,and get .500" on either side. Then,I consider the punch mark on center.

I hope this makes sense.

This sounds good. I'll try it. Now, except for the quill, do you lock the table?