How to use Edge Finders


(Peter Lundh) #1

Hi-

Does anyone have experience using a ‘Wiggler’ on the Nomad 883. Which wiggler set should I get, or is there a better option?

Many thanks.

-Peter


Using An Edge Finder - How to Get The Nomad Spindle to Turn When Setting Zeros?
Can anyone recommend an edge/corner finder for Nomad?
(Dang) #2

i’m looking too. Seems like a lot of center finders are at least 3/8" dia.


(Apollo Crowe) #3

We carry this 1/4" Edge Finder, you will just need the 1/4" collet to use it.
They are back in stock in the store- Made Right here in the USA by a really great guy who runs a family owned shop just up the street from us.
NOTE; set your spindle speed to 2k, no higher than that! It hasnt happened yet, but if you rotate the finder faster than that, you’ll probably explode it.


Carbide 3D shop link:


(Dang) #4

any good place to buy the collet and nut?


(Dang) #5

also how do you set the nomad to jog with the spindle on? ive only jogged it while it was not spinning.


(Joshua Hume) #6

FWIW @ApolloCrowe, I would really really really love to see a tutorial answering how to use this device with the Nomad.


(Mark Bellon) #7

any good place to buy the collet and nut?

Carbide3D!

.25" ER-11 Collet and Nut:

mark


(Dang) #8

it is sold out! i’m looking for ones in stock. lol


(Mark Bellon) #9

it is sold out!

ACK! Try Maritool. They are dependable source for collets and collet nuts.

mark


(Leith) #10

I would love to see a tutorial on this too, currently I have one but just use the back of a piece of carpet tape and a dowel pin to zero against my work pieces


(Mark Bellon) #11

I’ll explain the process of using a “classic” rotating mechanical edge finder here; videos are below.

Perhaps the biggest advantage of a “classic” rotating edge finder is the amazing accuracy and precision one can obtain at such a low cost. A high quality “classic” rotating edge finder can often be found for US$20 or less.

Make sure you’ve got plenty of lighting so as to see the edge finder clearly. One will also need eye protection. A mirror is useful to see those hard to get at locations.

An edge finder is perfectly round with a known diameter. A small section of it is detached from the rest of the body and machined ever so slightly off center - the “wiggely bit”. The “wiggely bit” wants to… wiggle as it spins. It sticks out from the main body when it spins.

As one moves the edge finder near an edge the “wiggly bit” will touch the edge before the main body. As one moves closer still, the “wiggly bit” will move closer and closer to the main body (less and less sticking out). Eventually, it seems to “snap in place” and the entire edge finder seems smooth. At that point, one is precisely touching the edge with the center of the edge finder one half a diameter away.

It’s AMAZING how clearly one can see the “snap in place”. When the edge finder does the “snap in place” it goes “perfectly smooth”.

It takes only a few tries - SLOWLY AND CAREFULLY - to see, understand, and internalize this.

One needs to run their spindle for this to work. SLOWLY AND CAREFULLY! Use a very low RPM! Many edge finders are designed with a maximum RPM of 750-1000 RPM. It doesn’t take much to see the wiggle clearly. DO NOT EXCEED THE PUBLISHED MAXIMUM RPM!

Precisely because they wiggle, edge finders do not like spinning at high speeds. Too fast and they can literally fly apart, potentially sending shrapnel at the user. Losing an eye is not fun… always use eye protection and stay below the edge finder maximum RPM rating!

Be sure to use decreasing step sizes as you get closer to the edge. The last few jogs should use the smallest increment available.

Using a high quality edge finder - and some practice - it is possible to hit zeroes with great precision. An accuracy/precision of 0.001" (0.0254 mm) or better is easily achievable.

On the machines I’ve worked on (before the Nomad), one enters a G code directly to the machine - “M03Snnn” (M03 - spindle CW; Snnnn - nnnn RPM; replace nnnn with a number, a slow RPM) - and the spindle will start moving. Then move the gantry/bed around to get near an edge. The rest is documented above. One enters “M05” (M05 - stop spindle) to stop the spindle when they’re done.

On my Nomad 883 Pro (and this should work for other Nomaden) this is the procedure for Carbide Motion (CM) version 356 and lower:

From CM screen/interface, click (and connect). Click on the job button. Clock on the “Spindle On” button. Now you can jog and go in and out of the zero screen. When you’re done, exit jog and the spindle stops (no need for an M05).

When you’re entering an offset (after hitting zero for that direction), enter negative D/2 and hit return.

The C3D edge finder has a diameter of 0.200" (5.080 mm).

BE VERY CAREFUL TO ENTER “M03S1500” EXACTLY. IT IS CRITICAL THAT THE EDGE FINDER SPIN AS SLOW AS THE NOMAD CAN GO (1.5K RPM) - AND NO FASTER!

Yes, the S1500 is below the official Nomad spindle bottom end (i.e. 2000 RPM). I checked with Jorge and it is OK to use this - BUT ONLY FOR THE EDGE FINDER!

Remember that the Nomad does not have reliable repeatability below 0.001" (0.0254 mm).

On the SO3:

Talking with @WillAdams we’ve determined that all of the SO3 routers (e.g. Porter Cable 450, Makita, Dewalt), whether they have a speed control mechanism or not, all spin much too fast to be able to use the C3D edge finder.

Sorry SO3 users!

The only way to use the C3D edge finder on an SO3 would require a VFD (e.g. SuperPID) to ensure an acceptably low RPM.

And now for the videos:

Here is a nice video showing how edge finders work:

And here is another. It includes some theory behind edge finders and demonstrates just how accurate/precise they can be:

mark

P.S.

No edge finder discussion would be complete without mentioning high end edge finders like a Haimer. Typically these devices are calibrated strain gauges. Strain gauges can measure INCREDIBLY TINY displacements accurately and precisely. An accuracy of 0.0002" is common with a 0.00005" repeatability. They are calibrated at the factory and unless one does something really nasty to them they NEVER drift.

The probe associated with a Haimer is a precision piece of equipment and is delicate. Use it carefully!

A Haimer and their like are used to measure the edge zero directly - no need to enter an offset. One moves them, much like above, until the tip touches the edge - and continues until the device says it at zero… and it is!

To achieve this kind of ability, these are large devices and require large shanks so they aren’t appropriate for a Nomad. They are also in the US$350-850 range. Really, really nice and super effective… a luxury item in some respects.



Carbide Motion 3D Manual - Issues With Zeroing
New Nomad/SO3 owner - where to look for Nomad newbie info?
How do i use the Edge Finder?
(Leith) #12

thanks! that is a very informative post mbellon, can’t wait to try it out


(Mark Bellon) #13

I own and use several edge finders (dealing with X0Y0):

A) Machinist’s dowels

This is the same method that @Randy does. Precision ground dowels of a known diameter. No spinning.

B) End mills themselves

This must be done very carefully to avoid damaging the end mill. No spinning.

C) Classic mechanical edge finder

I ordered one of the C3D ones (0.250" shank) because mine has a 0.375" shank (and the ER11 collet only goes up to 0.3125"). Spinning.

D) A laser edge finder

One of these, the one with the crosshairs: http://www.lasercenteredgefinder.com (NO SPINNING!)

I find that which one I use depends what I’m doing and how much I care about the “quality” of the zero.

For the best “quality” zero I use A or C, particularly when I’m working with harder materials (e.g. metal, wood, PVC, Delrin, HDPE). I don’t want to expose my expensive end mills to potential damage.

I use B when I’m in a hurry, the “quality” of the zero doesn’t need to be the best (but it does need to be good), the stock is a “soft” material, and I’m not using one of my expensive end mills. I often use this with machinable wax since it is very unlikely to damage an end mill.

With A and B I use a thin piece of material of known thickness… the “just able to pull” method.

I use D when I need a “pretty good quality zero” - usually when I’m working 2.5D jobs with parts that have construction tabs. I design in a bit of stock for the fixturing and being off a bit on the zero doesn’t really matter.

I’m done tests with D multiple times and I’m convinced that if I REALLY WORKED AT IT I could hit a quality zero with 0.002" repeatability. That would OK for many jobs… but I’ll stick with A and C when I want the best.

I’m convinced that the mountable version of D could provide the same 0.002" repeatability. The optics of these units are specifically designed for the optic hostile environment of CNC machines.

Hmmm… with all this edge finder talk maybe I’ll try D again and see what turns up… :wink:

mark


(Pete LaDuke) #14

First thing, “Thank you” for this write up, I have been trying to figure out how to use an edge finder with the Nomad and could not figure it out.

I did not know how to access the MDI screen.

Now that I do, I can start the Spindle with the M03Snnnn command. I can get my spindle to start, but after that when I go to my jog menu, it demands that I take two steps.

  1. Home machine, and
  2. “Measure tool” This is where I’m stuck now, because I just started my spindle spinning, I don’t want to measure it but Carbid motion does not allow me to avoid it.

Any Suggestions? What step am I getting wrong?

Thanks,

Pete


(Mark Bellon) #15

First thing, “Thank you” for this write up, I have been trying to figure out how to use an edge finder with the Nomad and could not figure it out.

I’m happy I could provide something useful to others. You’re welcome!

I did not know how to access the MDI screen.

OK!

Now that I do, I can start the Spindle with the M03Snnnn command. I can get my spindle to start, but after that when I go to my jog menu, it demands that I take two steps.

  1. Home machine, and
  2. “Measure tool” This is where I’m stuck now, because I just started my spindle spinning, I don’t want to measure it but Carbid motion does not allow me to avoid it.

Any Suggestions? What step am I getting wrong?

The directions in that posting were written for a much older CM. CM received a lot of update - including massive UI changes - in the last 2 months or so.

Recently I’ve been working on projects were I didn’t need to edge finder and so haven’t use the procedure. It sounds like the procedure needs to be update for the new CM…

I just tried a bunch of stuff and I do not see how to use an edge finder with the new CM! I hope I’m missing something but,as you’ve reported, I can no longer jump back and forth from MDI and jog.

Jorge, Apollo:

This was old procedure:

On my Nomad 883 Pro (and this should work for other Nomaden):

From Carbide Motion screen/interface, click (and connect), and hit the “m” key. This brings up an MDI screen. Hit the “Move Cutter” button and let the machine home and measure the wiggler. Now you’re back at the MDI screen. Enter the “M03S1500” and hit send. The spindle should start spinning. Exit MDI. Now you can jog and go in and out of the zero screen. When you’re done, exit jog and the spindle stops (no need for an M05).

When you’re entering an offset (after hitting zero for that direction), enter negative D/2 and hit return.

This appears to no longer work with CM 355. How does one MDI, get the spindle running, jog around set zeros? I don’t see how to use an edge finder anymore! I’ve got to be missing something!

Thanks!

mark


(Mark Bellon) #16

There is a new CM motion coming that fixes this…

mark


#17

Using a dowel pin to probe the edges fixes this too… :joy:

Randy


(Jeff the grumpy old dude) #18

I haven’t got to use mine yet, but I made a sheave and pressed it onto the shaft of my edge finder. Then I made an identical diameter sheave with a shaft to fit into my cordless drill.

When my edge finder arrived, it had a sticker on it saying 1500 rpm max. I looked at my drill and that was the max rpm on it.

When I try to use it I will drive the edge finder with my cordless drill / large o ring so as not to explode it. I have done that before on other machines and it could be dangerous!!!
They don’t like to see 5000 rpm or so. I don’t think it even got close before letting go