New Digital Edge Finder

[Susquatch]

Again I see accuracy thrown around when reading specs and referring to them in performance our equipment.

Regardless of the perceived accuracy of your scales and your DRO's display, what your machine is actual capable of is the determining factor and I'll bet that if you can get down to 1/10 of thou. you are doing really good. Anything beyond that is truly wishful thinking despite what your DRO says.

That said, a simple probe that is capable of a 0.0001 is more than accurate enough for 99.99% of us. For the few that have machines capable to go beyond that that gets into a different discussion.

Relax @Degen, we are on the same page. If you read my previous posts on this, you will see we agree completely. This isn't an exercise in improving my machining accuracy. I have no delusions about that. I can't reliably get to a tenth any more easily than anyone else - at least not directly. That kind of precision usually requires lapping or grinding.

Anyway, my very first post explains my objectives here and my reason for posting. This wasn't about machining in the real world. It was about calibrating my new DRO and some experiments to understand what is really going on with it. Is it as good as they claim?

In that context this isn't about how good I am or whether or not 0.0001 is reasonable or whether or not we are throwing unreasonable numbers around. It's about curiosity, learning, experimenting, and having fun.

We can certainly argue about the merits of good metrology equipment for normal machining, but at the end of the day, I firmly believe that my metrology equipment needs to be better than I am. I tend to prefer an order of magnitude better. If our measuring equipment is only as good as we are then we could be out double or triple what we think we are. But again, that's another matter and a whole nuther discussion.

 

[Former Member]

@Susquatch wan't directed at you just as a reminder for those lurking. I know you understand . Sometimes they miss the intent.

 

[Tom O]

Some people run them at a slow rpm and just get the led to flicker at the edge

 

[Susquatch]

Some people run them at a slow rpm and just get the led to flicker at the edge

That may work on some devices. I'm not sure how well it would work on either of mine. I've been impressed at the sensitivity of both. They are either on or off with no in-between at all. It is almost as though they have an internal Schmidt Trigger of sorts. They also seem to work well with or without oil.

When you think about the fact that any current flowing has to make the full circuit from/to the ball, through the part, vise, bed, saddle, knee, mill body, ram, head, bearings, spindle, holder, to/from the edgefinder body, with all the oil and grease in between, it's easy to see why they might have done that.

At three times the price of the Ali units, I'm not about to take either of mine apart to see what's in there, but maybe someone who bought an inexpensive off-shore unit would be willing to dissect theirs (or send it to me for dissection). I did look as closely as I could and got nowhere.

At any rate, they both seem to have extremely good sensitivity and excellent repeatability with no apparent signal leakage of any kind and rock solid edge detection at a much better level of precision than I ever expected. Certainly way better than I can ever expect to realize with my beginner level hobby milling skills.

Yes, I'm impressed.

 

[Susquatch]

@Susquatch wan't directed at you just as a reminder for those lurking. I know you understand . Sometimes they miss the intent.

I see. Sorry for the long explanation then. And of course you are right to make sure that others don't get the wrong ideas or the wrong expectations about all this. It would be easy to do.

 

[Susquatch]

double check again. I can't see them not having that in mill mode. If its true, that cancels my plan for getting a 4 axis for my mill to replace the 2 axis Mitutoyo. Damn

I spent more time looking at the tool store function and the SDM Function today. As I said earlier @Darren , even the tool store function for the lathe setup doesn't seem to be very good. I like the SDM capability WAY BETTER. The Lathe Tool store function only works in INC mode and then only for x and y. In the other hand, the SDM system is like 200 extra references all relative to ABS. I had no trouble coming up with offset schemes to accommodate tooling for all 4 axis.

If I do this for tools as you originally suggested, I will probably only do it for 10 or 20 tools. Not 200.

I really think you will be ok and I really don't think you would lose anything by going with the Ditron.