Probe hardware

Hi,

First I’m not a probe vendor and I have no financial interest in any of the probes mentioned below - these are just the ones I know of off the top of my head.

When I’m developing probing routines for MSM, well, ah software bugs can have a rather nasty/expensive consequence. :-(
I feel lots better crashing one of these vs. a $1k probe. :-) so I've been using the inexpensive probes.

At the low cost end seems to be one common design available from a couple of sources.

These probes are not bad – They're adjustable, does what it is supposed to and I find them it a good value for the price.

If you are just getting started, the accuracy of this probe design is probably sufficient. Other things have to get worked out before more accuracy is usable anyhow (See MSM manual section on probe mounting, accuracy etc).


Arnie's Probe
[info updated 11-2011]
Arnie (Zarzul on the Machsupport forums) designed, makes and sells an inexpensive probe.
See www.amelectron.com/
He can be reached at aminear@wyomingwireless.com
Price: $125
There are some pictures of the probe in the bargain basement forum of machsupport:
www.machsupport.com/forum/index.php/topic,17766.0.html


WildHorse Econo-Probe:
www.wildhorse-innovations.com/index.php?_a=viewCat&catId=17
$96-$120

Having crashed and broken a Wildhorse proe a few times and ordered repair parts, I've realized that this is a hand built product and “parts are not always parts”. Replacement parts have differed from prior parts (in dimensions, threads etc), so some tweaking can be required when replacing broken parts.

OTOH, I can buy a whole probe for less than what some others charge for a single replacement shaft/tip.

CNC4PC
Here is another source for the same probe basic probe design as the Arnie/WildHorse:
$125
www.cnc4pc.com/Store/osc/product_info.php?products_id=323


Rockler woodworking:
I have seen this on their web site but don’t know anything about it other than what their site says.
$300
www.rockler.com/product.cfm?page=22582

IMService:
www.imsrv.com/deskcnc/probe.htm
Hard to know, but it looks in pics to be the same probe as the one sold by Rockler.
$325
FYI - There is no "add to shopping cart" button for the probe on their site (wasn't there 18 months ago when I first looked either). You'll have to ask them how you buy one of these. I did see one at the CNC workshop last year so they do exist.

Tormach:
Tormach has lots of things - including a probe.
www.tormach.com/Product_TTS_electronics.html
$1100+

[update 11-2011]
Tormach also now sells a "passive probe" for $210
www.tormach.com/product_tts_passive_probe.html

Renishaw:
There is a reason probes are often called “Renishaw probes” – in that respect “Renishaw” is like “Kleenex” – their name has become a generic term for probes.

Go here to see the standard of the industry (bring a fat wallet);
www.renishaw.com/en/machine-tool-probes-and-software--6073


Dave

At the hardware level, a probe input is just a switch contact.
Touch plates tend to be normally open (NO) where the tool touching the plate grounds the input the BoB.
The 3d probes tend to be NC - the probe tip touch causes an internal contact to open.
Using both leads you to need either something like the little circuit in section 6 of the MSM manual (as mach has only one probe input signal), or a BoB that can do the equivalent for you (one that I know of is the PDMX 126 BoB).

At the MSM software level, there are some additional concepts that get handled: 3D probe tip diameter; effective probe tip diameter; touch plate thickness etc. - These are all handled by MSM for you.

If you really want to try it on the cheap - load up the parallel port driver and assign a key to emulate the probe input (only works in mach with the PP driver, key emulation doesn;t work with the SS).

I use F12 for initial testing for probe routines before I go to the real probe and mill - you can think of this a a rather geeky video game.... how close can I get the zero point to where I want it using F12?

Dave

Tom,
Thanks for letting us know about the IMServ probe not being adjustable.
I have been wanting a smaller probe as I have limited Z height - but sounds like this one is not a candidate.

As there is not data on the web site, what are the approx dimensions of that probe?
(Diam, mounting shaft length, body length and tip shaft length are what I'm curious about)

Dave

Here's a photo of my Wildhorse next to the PerformanceMotion set up for tool length measuring, but it gives you a feel for the relative sizes. The Performancemotion is tiny!!

For the record, my Imserv had .030" runout, but that was in fact adjustable by tweaking how tight the 3 screws holding everything together are. Not easy at all, but uses the same procedure you would use with the Wildhorse. Just not too easy to get to those screws. I used a collet holder, and left enough room to get a screwdriver bit in there, and used pliers to turn it. Got it within .001", but being a plastic body, wonder how long that will last with temperature changes....