Audible (CLICK) Edge Detector ?

[Bob La Londe]

I've used the little edge detectors from Fisher Machine for a few years now.
If I take my time and bump up 5 tenths at a time on the little CNC mills I
get pretty good results. Better than the machine itself. Good enough for
rubber worm molds anyway. I've never used the audible ones. No, not an
electronic thing, but a mechanical "click" when it breaks over. How good
are they? Does the mechanism that makes it click have a negative impact on
accuracy?

Also, is Fisher still making edge finders? I tried to visit what I thought
was their website and got a link farm page. I could have sworn I first
bought them direct thru Ebay then from their site, but I couldn't find
either. Just a few from third party seller.

One more question. How does a ball on a rod type wiggler compare for
accuracy to an edge finder? Seems to me that backing off and coming back in
slowly to get your final result would be kind of tedious with one of those.
My reason for even looking at them is because they kick so far back and up
when they hit that damaging crashes would be virtually eliminated.

[Jon Elson]

Bob La Londe wrote:

> I've used the little edge detectors from Fisher Machine for a few years
> now. If I take my time and bump up 5 tenths at a time on the little CNC
> mills I
> get pretty good results. Better than the machine itself. Good enough for
> rubber worm molds anyway. I've never used the audible ones. No, not an
> electronic thing, but a mechanical "click" when it breaks over. How good
> are they? Does the mechanism that makes it click have a negative impact
> on accuracy?

I got one of the audible ones, it seems to work, and can be heard pretty
clearly even when wearing ear protectors. I'm now using an electronic probe
in most circumstances, but still keep the edge finder for when the probe
won't fit.

Jon

[et...@whidbey.com]

On Sun, 18 Jun 2017 21:35:05 -0500, Jon Elson <el...@pico-systems.com>
wrote:

How do those audible click edge finders work? What makes the click?
I've only seen them in catalogs and the pictures have never been clear
enough to show what does the clicking. The edge finder I like the best
is a "Super Jump" edge finder. I think Flexbar sells 'em. I have
several edge finders but the Super jump gets the most use because it
is the most accurate and most easily visible.
Eric

[Jon Elson]

et...@whidbey.com wrote:


> How do those audible click edge finders work? What makes the click?
> I've only seen them in catalogs and the pictures have never been clear
> enough to show what does the clicking. The edge finder I like the best
> is a "Super Jump" edge finder. I think Flexbar sells 'em. I have
> several edge finders but the Super jump gets the most use because it
> is the most accurate and most easily visible.

It is built just like the usual edge finder with the concentric parts with a
spring to hold them together. The difference is there is a small flat
ground on the side of the feeler tip. You could turn a standard edge finder
into the audible type by just grinding the side of the tip.

Jon

[Bob La Londe]

"Jon Elson" wrote in message
news:oZ6dnUmgv8Nu89TE...@giganews.com...

*******

I just bought a couple "click" edge finders. Maybe its worth a little video
for others to show how they perform.

I can setup a couple on the Hurco easily enough. Makes a nice machine for
it. It will turn as slow as 100 RPM the way its currently tuned, I like
1000RPM on it for edge finding. I hope they will work on the little 24K
machines, since about 4K is the slowest they will turn reliably, and Fisher
labels them as 1500 max. I've been using the non-click ones on the high
speed spindles and the only time I have damaged one is when I looked away
while jogging and tore the tip off, or hit goto zero before resetting zero.
I know if you accidently hit start with the spindle set at 24K they just
come apart before you can stop the spindle. Heck before it even reaches
speed. Since the click type are inherently out of balance I hope I can spin
them at 4K without coming apart. I'll let you guys know.

[Carl Ijames]

"Bob La Londe" wrote in message news:oigssn$kp5$1...@dont-email.me...

===============================================================

Could you grind a matching flat opposite the original flat to balance the
tip? Might be easier to start with a normal tip and grind both flats in
your own fixture so you know that they are matched, rather than trying to
duplicate an existing flat. You could put the end down into an empty soda
bottle to catch the pieces as you "test" :-).

--
Regards,
Carl Ijames

[Bob La Londe]

"Carl Ijames" wrote in message news:oih5...@news3.newsguy.com...

***************************************************************

Carl,

First Test:
I did a test today. They worked perfectly. I tested with a standard edge
finder, set the offset and then retested with a click type. I tested on the
little high speed machines, but I just happened to have the cabinet open and
look at the frequency output of the VFD. At 4K set it was only putting out
21.8hz. That's only 1300 RPM. I'd never checked the speed of the spindle
at below spec speeds before. Just from 10K to 24K. I nly use them from
about 18K to 24K for cutting. In those ranges they are dead on. I guess
the 0-10V signal is not accurately proportional at those speeds. Anyway,
both high speeds turned out to be the same. At 4K set they are turning
about 1300. I was running them within their speed spec all along. Anyway,
the click type started clicking at EXACTLY the same offset as the regular
type kicked over. The sound was clear and distinct. I was setting up a
job, so I set the height and started the machine shortly there after.

Second Test:
It worked just like the first except I had a hard time hearing the clicking
over the background noise of the other machine. In fact I wasn't sure I was
hearing it at all until I put my head inside the cabinet. It worked though.
Just like before.

Conclusion:
For a hobbyist or a manual machine shop that only ever has one machine
running at a time this thing is awesome. Dead on and much easier than just
a visual indication. For a shop like mine where I can have 3 or 4 CNC
mills, and a band saw running at the same time... eh! Maybe not as awesome.
Accuracy was identical in testing to the regular edge finder.