[outsider787]

I'm looking for a touch probe to use for things like edge finding and some digitizing.

The only reasonably priced probes I've come across so far are the Tormach Pasive Probe at $209, and the CNC4PC Touch Probe at $135.

Are those two probes similar? Build on the same principle?

Are there any others I should be considering for general purpose usage?

[SCzEngrgGroup]

Yes, those are both functionally identical, and both operate on exactly the same principle. I suspect the Tormach one may be slightly better quality. The CNC4PC one is made by WidlHorse Innovations (Wildhorse Innovations). Personally, after years of probing, I've found the best probe to be a piece of 1/4" drill rod in a collet chuck, and a piece of copper-clad PCB material wired to the PROBE input on the computer. If you have a crash, it costs nothing to replace, there's no adjustment required, and no moving parts to go wrong on you. It's all I've used for several years.

Regards,
Ray L.

[Analias]

Ray, do you have a fixed (mounted on the bed) and a "mobile" probe?

I used a fixed and mobile probe on my router table and it works so nice I want something like that for my X3. The mobile plate is for determining work height and the fixed plate is for determining tool height.

I've been contemplating how to mount it on the table since the plate is typically positive and would need to be insulated from the table bed. On the router table the I use a piece of aluminum bar stock and this hasn't been a problem since the table surface is plywood.

I was thinking of using a piece of 3"x1" PCB and either use double sided tape or clamp it down and isolate the screws from the positive side of the probe by cutting a light slot between them. I would expect the glass epoxy of the PCB to be fairly stable and wouldn't change thickness with coolant or ambient temp changes.

[SCzEngrgGroup]

I use just a piece of PCB material, with the copper side wired to the PROBE input, along with a pullup-resistor. The input is then normally high, and when the tool touches it, it goes low. I use this for ALL of my probing, for setting X/Y/Z/A zeroes, measuring tool length, everything.

Regards,
Ray L.

[outsider787]

Ray,
Thanks for the advice.
How do you deal with finding hole-centers of non-metalic parts? (using either OD or ID of the part)

I too currently use a 3/8" drill rod and a PCB board (in a similar matter as you). Working with metal parts is simple as the part is conductive, and touching the part brings the input low. Same for flat non-metalic parts where I can use the pcb board.
When it comes to non-flat, non-metallic parts, I don't have a solution yet, hence the probe.

[mhackney]

I've been using the Wildhorse probe for 2 years with good results for X, Y, Z and center finding. All of my fixtures have a bored and reamed .0375" hole centered at 0,0 so I can quickly dial in the fixture (thanks to Ray for the fixture design).

I am contemplating building a touch probe similar to what's described above but insulating the drill rod (I'll use .125" precision ground) from the collet with a nonconductive material. That way I can touch off directly on the stock surface. If I need to touch off on plastic, I'll use the Wildhorse or a piece of PCB.

The primary reason for going this route is alignment. The Wildhorse does have adjustment screws to align the probe. Once aligned, you have to be careful to position it and the spindle in the same orientation every time. Not a big issue but a little annoyance. And as Ray mentioned, a crash can make a mess with the mechanical switch probes - don't ask me how I know!

cheers,
Michael

[amyers]

hoss2006 did a very cool page on probing, i downloaded one of his screen sets. Automatic Tool Probe - CNC - The Hossmachine Forum

[amyers]

When it comes to non-flat, non-metallic parts, I don't have a solution yet, hence the probe.

this video shows how the tormach probe handles something like this, plus these probes are used for digitizing purposes too.

[ame=http://www.youtube.com/watch?v=jf2BaJ0N_ZA]Finding the center of a circle using a probe on a Tormach 770 - YouTube[/ame]

[SCzEngrgGroup]

I haven't had to probe anything but edges in ages, but when I did do a lot of that I used an inexpensive Fowler electronic edge finder (see Enco P/N 307-3436). I would remove the batterys, and run a wire to the tip, and out the side, turning it into a nice, passive, rigid probe. The rigid part was a problem with Mach3, as it would often do stupid things when probing, and break the tip. I no longer have that problem with KFlop, so I will get another one next time I need to do any probing of holes or center-finding.

It's very difficult to make your own, and get it really precisely centered, without being able to grind it on-center after mounting. I tried a few times, and could never get it better than a couple thou.

Regards,
Ray L.

[amyers]

I used an inexpensive Fowler electronic edge finder (see Enco P/N 307-3436). I would remove the batterys, and run a wire to the tip, and out the side, turning it into a nice, passive, rigid probe.

Regards,
Ray L.

exactly as hoss described on his page posted back in 2008. is that where you got the idea?

[SCzEngrgGroup]

exactly as hoss described on his page posted back in 2008. is that where you got the idea?

No, I was doing it long before that.

Regards,
Ray L.

[amyers]

sure, sure.

[outsider787]

Ray,

Does the edge finder you mentioned detect Z edge? Or just x and y?

[SCzEngrgGroup]

Ray,

Does the edge finder you mentioned detect Z edge? Or just x and y?

It's a rigid probe, so it's just as capable of detecting Z. The only downside is it has zero tolerance for being over-driven, so you have to probe slowly enough that you can stop VERY quickly once contact is made. And, you have to pray Mach3 doesn't do something stupid and over-drive it for you. That was the problem I always had - Mach3 would just do unpredictable things - move the wrong axis, move the wrong direction, over-shoot, etc. I must've broken a half dozen of those things before moving to the KFlop, and putting an end to all that foolishness.

Regards,
Ray L.

[691175002]

I made a pair of rigid probes way back.



As ray said the probes get bumped around a bit and mine is nowhere near concentric so I use a real edgefinder if it matters.

The disk is great for setting tool heights after a change since I don't have TTS yet. Repeats to +-0.0005" in my experience.

[RTP_Burnsville]

I've been using the Wildhorse probe for 2 years with good results for X, Y, Z and center finding. All of my fixtures have a bored and reamed .0375" hole centered at 0,0 so I can quickly dial in the fixture (thanks to Ray for the fixture design).

I am contemplating building a touch probe similar to what's described above but insulating the drill rod (I'll use .125" precision ground) from the collet with a nonconductive material. That way I can touch off directly on the stock surface. If I need to touch off on plastic, I'll use the Wildhorse or a piece of PCB.

The primary reason for going this route is alignment. The Wildhorse does have adjustment screws to align the probe. Once aligned, you have to be careful to position it and the spindle in the same orientation every time. Not a big issue but a little annoyance. And as Ray mentioned, a crash can make a mess with the mechanical switch probes - don't ask me how I know!

cheers,
Michael

Hi Michael,

Do you happen to have a link to the fixture design? After spending the past couple days making a fixture to do Cmas gifts this year I am certainly open to suggestions.

Thanks,
Robert

[mhackney]

Yes, I describe it with drawings on my X2 thread.

Very simple, very effective, very repeatable.

cheers,
Michael

[outsider787]

I must've broken a half dozen of those things before moving to the KFlop, and putting an end to all that foolishness.

Ray,
What is this "KFlop" that you're referring to?
You've mentioned it in a couple of posts in this thread already.

[RTP_Burnsville]

Yes, I describe it with drawings on my X2 thread.

Very simple, very effective, very repeatable.

cheers,
Michael

Thanks Michael......

Robert

[SCzEngrgGroup]

Ray,
What is this "KFlop" that you're referring to?
You've mentioned it in a couple of posts in this thread already.

Dynomotion | Motion Control Boards

Regards,
Ray L.