I was taught a new way to use an edgefinder today. What are your thoughts?

I have 2 edge finders. One is a Fisher and one is a cheap, generic no name. Both have 3/8” barrels and .20” probes. Just for grins, I experimented a little with both this morning.

The difference between the Fisher and the generic when using the conventional method to find the edge was ~.0005” (5/10ths).

Then I compared the conventional edge finding method to 9t8z28’s trainer’s method with both finders. With the Fisher, the difference was ~.0006” (yes, that’s 6/10ths). But with the generic, the difference was a whopping .008” (yes, that’s 8/1000ths). The interface between the barrel and the probe of the Fisher is noticeably smoother than that of the generic, which I suspect explains the larger spread between methods with the generic finder. The interfaces of both finders were lightly oiled.

Measurements were taken with a Mitutoyo dial test indicator with .0005” scale increments and the edge being found was the fixed jaw of a screwless vice.

Now back to our regular programming.

Tom
 
When I find the edge of softer plastics like nylon, I reduce my speed to 200 RPM and use my 1/2 " edgefinder. I haven't noticed any marks, yet!

Nice description, RJ!
 
I dont like to leave it rub to long either. I pull up the quill as soon as it kicks out. I know some guys who put a drop of light oil in between the tip and the part but I dont like that idea.
Bob Korves said:
I don't like to leave the cylinder rubbing on the work for long, figuring that will cause wear in and on the edge finder. I go in once fairly quickly, then once slower, backing out immediately after seeing the number. On something more fussy I go more slowly, and had most of RJ's excellent and eloquent post figured out, but use it rarely when I am trying really hard to get it right.
Click to expand...
 
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Never having used an edge finder and doubting if I will ever be able to afford a mill unfortunately I never the less found this a very interesting discussion.
Thanks to all concerned.
(no knowledge is wasted)
 
I worked with an old English toolmaker who would normally use the contact until running rue method, however when he was doing more accurate work he would would do as mentioned earlier in this thread of putting a light or white card behind the edgefinder and watch until the light stopped blinking to obtain the edge. He maintained that the way he could guarantee he was within.0001"
Just a little more food for thought...
 
hmgnz said:
I worked with an old English toolmaker who would normally use the contact until running rue method, however when he was doing more accurate work he would would do as mentioned earlier in this thread of putting a light or white card behind the edgefinder and watch until the light stopped blinking to obtain the edge. He maintained that the way he could guarantee he was within.0001"
Just a little more food for thought...
Click to expand...
Interesting idea, and probably works well, but requires good light, very good eyes, a perfectly parallel with the cutting face viewpoint, and nothing in the line of sight interfering, like perhaps oil, coolant, swarf, or the part itself if it is at all concave.
 
higgite said:
I have 2 edge finders. One is a Fisher and one is a cheap, generic no name. Both have 3/8” barrels and .20” probes. Just for grins, I experimented a little with both this morning.

The difference between the Fisher and the generic when using the conventional method to find the edge was ~.0005” (5/10ths).

Then I compared the conventional edge finding method to 9t8z28’s trainer’s method with both finders. With the Fisher, the difference was ~.0006” (yes, that’s 6/10ths). But with the generic, the difference was a whopping .008” (yes, that’s 8/1000ths). The interface between the barrel and the probe of the Fisher is noticeably smoother than that of the generic, which I suspect explains the larger spread between methods with the generic finder. The interfaces of both finders were lightly oiled.

Measurements were taken with a Mitutoyo dial test indicator with .0005” scale increments and the edge being found was the fixed jaw of a screwless vice.

Now back to our regular programming.

Tom
Click to expand...

Very interesting but can you verify which result was closed to the true edge? .008 is probably unacceptable to most of us.

Robert
 
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