Electronic edge finders - any recommendations?

[bevinp]

While I would love to buy the Tormach probe, the cost is above my budget. So I am looking to buy an electronic edge finder and would love to hear any pros/cons about the current offerings from the credible manufacturers - Fowler, Borite, Pec, SPI and other brands.

And if anyone has the opinion that the electronic edge finders with a spring mounted contact ball do not produce consistent readings, please tell everyone your story.

Thanks,
Bevin

[tobyaxis]

I use a Mechanical Edge Finder from Brown & Sharp (10years old), and used one electronic.
The electronic will break easily even if dropped 12" onto a wooden table.

[bevinp]

Toby,
Yes I have a mechanical one that I could never get to work properly, until I saw a Youtube of one working correctly. I realised that mine is poor quality and on closer examination I found that the .200" dia end is not square to the body and has significant runout at its end. Also it is out of round by about 0.0005". I thought it was a little cheap when I bought it!!!!

I am hoping that an electronic edge finder (a good one) will be easier to use (not require spindle running).

Did you use yours much before it broke? What brand was it? Did it have the overrun protection?
Bevin

[MichaelHenry]

Here's a real nice mechanical edge finder:

https://www.hschmidt.com/productcart...&idproduct=148

Mike

[BobWarfield]

I have both Starrett mechanicals and a Fowler electronic (LED) edgefinder. The Starrets work fine, but I found the Fowler faster and easier.

I did eventually manage to break it, but only after I had CNC'd my mill and jogged a bit too far and fast. LOL, I have broken a 1/2" endmill doing same while it was running--stuff happens!

In other words, I haven't found them too delicate. The best news, is I took the Fowler apart and I'm able to convert it for use as a touchprobe talking to Mach3. It works reliably with an ohmeter, so I just need to wire it up to Mach and set up the screens.

Really handy little gadgets to have.

Cheers,

BW

[zephyr9900]

Originally Posted by BobWarfield ... Fowler electronic (LED) edgefinder.

Bob, is it this one? I'll be very interested to hear about your Mach probing results.

Randy

[BobWarfield]

Yes, exactly.

I'll eventually get a chance to fool with it and get it working, at which point I will document on the web site. I haven't gone further than to hook it up to the ohmeter and try it. Frankly, I needed it one day and was annoyed when my jogging broke it (LED stayed permanently on and I never did figure out why).

Here's the deal. If you unscrew the battery compartment, there is a battery, and below that there is a little LED assembly in a plastic tube that just drops out.

I took the little plastic tube a 3/16" endmill arrived in and discovered it fits nicely into the edgefinder. I drilled the end and stuck a wire down it and out the hole in the bottom of the plastic tube. Stuck a 1/4" dowel pin into the top of the endmill holder to wedge the wire in place and drilled a hole in the side of the edgefinder at top for the wire to come out. I needed a little heavier spring between this assembly and the battery cap to reliably hold it in place, but that's all there is to it.

You get a contact closure between the body of the edgefinder and the wire, which connects to the tip inside the black insulated area just by rubbing against it, whenever the edgefinder contacts the workpiece.

Refer to Hoss and others to see how to set up the screens and such for Mach3 to use this as an edgefinding probe.

For those that have broken their edgefinder, this may provide interesting new life for it.

Cheers,

BW

[zephyr9900]

Bob, since the Tormach version of Mach3 is already set up for probing I'm imagining that, assuming your edgefinder mod works electrically (and why shouldn't it? ), it would literally be "plug and play" with the appropriate connector. It would definitely be worth buying a new one and hacking it.

Randy

[silverfoxx03]

www.haimer-usa.com

go to the sensors--the best of the best there. Quite a variety and priced well.

[benji2505]

Originally Posted by bevinp .... I am hoping that an electronic edge finder (a good one) will be easier to use (not require spindle running). ... Bevin

Bevin,

I have the Fowler LED solution as well. He only difference to the mechanical edge finder is the LED/ battery gismo. You will have to turn on the spindle and move until you get a full LED-on. Before that you have an on-off signal that comes from the runout of the edge finder.

I frequently use the electronic edge finder to check the travel in x and y direction with some gage blocks. If you know the shortcomings they work well.

99% of the LED edge finders that I have seen/wrecked/shot through the room have a runout. The shaft that holds the contact area is flexible and bends easily. Use a collet holder.

That fact throws some wrinkles on my forehead concerning the probe solution addressed earlier.

Expect the tip to be between 0.199X and 0.200X. Pretty sad for a precision instrument, but it is what it is. I am adjusting for it in the tool table.

Have fun.

Benji

[Superman]

We use a SPI 3D Alignment indicator
on some of our smaller CNCs that don't have autogauging

-allows for a fair bit of travel
-the actual stems can be fragile ( ceramic base ?), They are sacrificial ( they break before anything else )

[R.DesJardin]

I had always used a mechanical Starret edge finger until I bought my Tormach. I then tried out a Electronic one and found for the accuracy most of us need it is faster and easier to use plus I also use it for my T0-Z0 setting.