I figured out the home made touch probe for

[seanreit]

Tormach. You get the din connector at Fry's for .69 cents, wire up pin 4 and 5 (it's stamped on the din connector). Put one lead to ground on your machine, and the other on a metal part. You have to shield your metal probe, I used acrylic I had in the shop (scrap).

Make sure in ports and pins that input 13 is your probe.

Set tool 99 to the diameter of your bit plus the thickness of your plate, name tool 99 "probe".

Now go to the mach3 screen for probing, and it should work no problem.

One area I have not figured out, is on my y axis, it works perfect, but on my x axis I am always off the radius of the bit. I think it's a code problem in mach, but I will try to figure that out later. This works really really well!

[seanreit]

http://shop2.frys.com/product/157080...H:MAIN_RSLT_PG

[Freddy Bastard]

That would be cool if you could post some pics of your probe, or maybe a small video of it working. Very nice!

[seanreit]

I'm uploading video to youtube right now, it will be available shortly under username seanreit

I used 22guage wire I had laying around the shop. I can't speak for any other device than what I used. In my video, I upgraded my probe to a piece of aluminum angle glued to acrylic. This is the same material the tormach shield slide out is made of, sold at home depot for about 7 bucks a sheet.

[seanreit]

YouTube - probe

YouTube - probe

[seanreit]

YouTube - DSCN1949.MOV

YouTube - DSCN1949.MOV

[Art Pentz]

Hi,

This functionality has been discussed on the Yahoo Tormach group.

It is not a good idea to connect any of the probe connections directly to machine ground per Greg Jackson at Tormach.

You need to use a relay or optoisolator to interface the probe DIN connector to your probe.

I use a probe like this using a 9V battery and reed relay all the time for Z height setting.

It is very accurate and repeatable.

Best regards;

Art Pentz

[seanreit]

Hi Art, can you describe the process you refer to and the components in great detail? I am not the sharpest in the group, and I have been wanting to do this type of zero setting for two years, and finally broke down yesterday to start working on it. I'm very excited about it.

[Art Pentz]

OK, here's the post I made on the Yahoo Tormach group:

Hi All,

As I mentioned in a previous post, I've been playing w/ the Tormach
probe. It is a REALLY useful tool - so useful that I decided to make a
holder that magnetically mounts to the Tormach control panel door for
easy access. I use this thing at least 10 times a day - it's great!

The furnished probing screens are quite useful, but seem to be limited
to setting X,Y zero and finding the center of circles and pockets
(inside measurements). It would be nice if there were more options for
outside probing - finding the center of rectangles and measuring
distances.

The repeatability on my machine is quite good and would greatly
benefit from some additional probing screen automation.

While playing w/ the probe, I decided to check out the " Z height tool
setting" screens. This lead me to wonder how the automatic probe
screens could be used to automate the tool "Z" zeroing required for
every new operation.

Most of the "tool presetters" I've seen for sale have quite a large
base diameter which precludes their use on smaller pieces of stock.
They also require manual entry of height parameters.

***********************************************************************
Disclaimer - Just because I did this doesn't mean you should - you're
on your own...

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

Since the circuitry for the Tormach probe function must be isolated
from the machine chassis ground, a relay or optoisolator is required to
interface the probe/toolsetter.

I visited the local Radio Shack to see what was available - pretty sad
to see what has happened to the component availability at he
modern 'shack.

It cost me less than $10.00 for a 5v regulator, reed relay and 9v
battery clips. These components can be purchased for MUCH less on the
Web, but I like to support the local guys. Sometimes I need stuff on
Sunday...

A 9v battery feeds the regulator (input/ground)which drives the coil
(output/ground)of the relay. The NO contacts of the relay short across
the probe pins 4 and 5 when power is provided. By cutting one of the
battery clip leads (in my case the + lead), grounding one side to the
chassis and extending the other to my "toolsetter" (any hunk of metal
w/ an insulating layer between the toolsetter and the stock).

This means that the + battery lead is connected to the tool through
the machine chassis and the + input to the regulator is connected to
the "toolsetter" The "toolsetter" must be electrically insulated from
the stock being "zeroed to".

My theory was that 9v would be able to travel through the way oil and
sliding surfaces better than a lower voltage and the regulator would
ensure that the coil of the relay would "see" the rated 5v.

Experimentation proved to be troublesome as the system worked
perfectly until the lead to the toolsetter was lengthened to over 10".
I spent several hours messing around w/ this issue until I noticed that
the signal was much better when I was holding the relay/regulator in my
fingers - Ah-Hah! must be a capacitance issue.

I then soldered a 2.2 MFD Tanatlum capacitor across the battery leads -
no further problems... Why did I choose that value of capacitor? It's
what I had (probably 10 years old).

If you use a Tanatlum capacitor be aware that they are polarized and
will explosively let out their magic smoke if connected backwards.

Another note: reed relays are very fast acting, but can be adversely
affected by vibration and external magnetic fields. An optoisolator
would eliminate these issues.

My BIG question was " how quickly will the reed relay/software respond
to the contact closure between the tool and the toolsetter"?

Will the tool be forced into the toolsetter and break the tips of the
cutter before the steppers retract? Does the toolsetter need some
spring loaded compliance to deal w/ the overtravel? What is the
electronic latency (delay) inherent in the Mach circuitry? Visions of
Zeno's paradox dancing in my brain...

Anyway, it turns out that the relay/circuitry/probe software is so
fast that the cutting tool will not mark the toolsetter AT ALL.

I am getting Z repeatability of about .0005" w/ a crude piece of
aluminum w/ a nylon washer glued to the bottom. Not as precise as the
Tormach toolsetter - but pretty darn good!

The really nice thing about the furnished Z height screens is that you
can have the Tormach precisely measure the height of your toolsetter
automatically.

Just surface a piece of stock, stop the mill while the cutter is at
the facing depth and zero the DRO. Then insert your electrically
connected "toolsetter" between the tool and the newly faced stock(any
piece of conductive stock w/ parallel top/bottom and an insulating
layer on the bottom).

The probe screen will lower your tool slowly to the top of the
toolsetter and then retract - recording the measured height of the
toolsetter.

You can then use the toolsetter to set the "Z zero" on any piece of
stock that the toolsetter will fit on. The software will automatically
deduct the toolsetter height to give a true Z zero height for your tool.

You can have several different toolsetters for different applications -
like measuring pocket bottoms etc.

ALWAYS ALWAYS ALWAYS verify that the toolsetter is able to signal the
software by touching the toolsetter to the tool prior to probing. If
the software does not receive the signal to stop/retract, the tool will
be driven into the toolsetter w/ destructive force. Good habits will
keep you out of a LOT of trouble!

This toolsetter has changed the way I work. In combination w/ the
Tormach probe, the PCNC machine continues to amaze me w/ its quality
and versatility.


Best regards;

Art Pentz

[kprice1658]

Another option is this cable at Radioshack :
http://www.radioshack.com/product/in...ductId=2103840

Its a 6' cable with a connector on both ends....cut it 1/2, you end up with 2
3' cables to play with...