Feed Hold Switch

Has anyone setup a feed hold/pause button on their pro yet? (not an emergency stop/panic button which should be hardwired and cut power completely).

I noticed that there is a feed hold LED on the board, near the limit switch LEDs, but haven’t gone and poked around yet with a multimeter.

I also noticed on the Z limit switch connector that there were a few other letters silk screened onto the board, including Y2 and F. F seems like it might be the feed hold.

I emailed support and they said this was unsupported so I’d need to ask the community (this was a little disappointing…).

I’m not sure if the LED is just an indicator from the software side, and there isn’t an actual corresponding input, but I figured I’d ask them officially before guessing and shorting random signal wires on my board :.

If the feed hold works the same as the older controller boards then;


Thanks! I think that requires CNCJS, which I’m not looking to switch to at this time.

I believe I’m clear on the mechanics of how the feed hold works, just want to identify where on the new Pro CM boards the feed hold signal will go. The new boards don’t look like any of the pictures in the other various feed hold threads.

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Can you share a good pic?
By default, feedhold is on A1 of the ATMega328. A simple momentary switch to ground that pin will work (if it’s available in the board).

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While I can’t comment about the new Pro controller boards (but pretty sure the “F” silkmark is where it’s at, indeed), here’s a thread about everything Feedhold on the Shapeoko,

and of interest to you is the part about how Carbide Motion behaves. You can definitely use a physical feedhold button with CM, you will just have to push the button AND click start in the UI to resum after feedhold.

I’m as interested as @neilferreri in getting a good pic of the Pro controller, for later reference in the community for this kind of things that are not (yet) officially supported.

I don’t have a pro, but I thought from what I read that the round blue led button on the right hand front side was a feed hold?

I may be wrong because I can’t find where I read it again.


That would have made sense. It’d be nice if it was a feed hold and resume switch.
Pretty sure they said it was the power, though.

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I believe you can use a momentary switch on the feed hold pins. If I recall correctly it has the same effect as hitting pause in Carbide Motion. You then have to resume using the on- screen button. That is from memory though, and I can’t remember my own age half the time. :smiley:

The right hand, blue ring button is a power button. It can be used as an estop in a way the same as the in-line power switch in big time mess-ups.

Personally, one day I want to add an estop in the left side… like the blue power, but a red momentary switch that sits proud of the end plate.

Well, you could end the thread of you confirm that the feed hold is broken out to an available connector.

For a true estop, I’d use a switch that actually cuts power. Using a momentary switch would rely on other components.
If you get a paddle or mushroom switch, make sure it’s accessible but not going to be bumped accidentally.

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Looks like it is covered in depth here:

I have an iot relay on my Original XXL, and a BitRunner V1 on my Pro. So in my case I have the extra equipment to make it a true feed hold. You’re correct, in my last paragraph, I should have used feed hold instead of estop when referring to the monetary switch. There could be a slight delay using the bed hold pins as it decelerates so position is not lost as opposed to an estop hard stopping and requiring a reset.

I’ll try and get a good picture of the PCB today after I’m done surfacing.

More Pictures located in the album here: https://imgur.com/gallery/kVwA9XH

Didn’t have time today to sort through these and rotate/annotate/etc.

Here are two:


If you connect the pin that’s labeled F, on the 8p connector, to ground does the FeedHold led turn on?

You’d have to ultimately add a pin to one of the housings. A momentary switch that connects the pin to ground would work.
I’d guess that based on what I see, but I have no way to confirm for you.
I see A2 and A3 are broken out. A2 is the cycle start which would be nice to have.
Without a way to test, I’m just reporting what I see. There could be logic on the board that could change the behavior of any pins or the silkscreen could be misleading.
Make sure you feel comfortable with what you’re doing and test before you use it “live”.


Not about Pro, just about hardwiring a pause switch: I just want to relate a story that proves that having a hardwired feed/hold switch is not only the same as the pressing the Pause button on CM, but BETTER.

Last week, I was distracted by someone in my shop while I was in the middle of changing bits. The Shapeoko was going through the sequence for the BitSetter probe when I realized that the spindle was still on and the Z was about to plunge into my bitsetter. I wasn’t even sure if it was going to work, but I pressed the pause button and the workflow stopped immediately. I was able to turn off the spindle and wait for it to spin down. When I pressed the pause button again, the workflow picked right up and continued the probe sequence properly. There was NO Pause button available in the software at that point - no resume either. Pressing the pause button the second time, at that point, restarted the bitsetter probing sequence without any software interaction. My only recourse, if I didn’t have the pause switch hardwired, would have been the panic paddle…and I was in the middle of a job that had already been running for more than an hour.

Definitely hardwire a Feed Hold. It’s SO much better than searching for the software button with your mouse…and sometimes, it’s available when the software button isn’t!


My last two-cents: @Luke @WillAdams @robgrz : Why not make a physical feed hold part of the product and not a DIY project? It literally cost me $6 USD retail to implement…for you in bulk, likely less than a dollar. It not only helps CM users, but anyone who uses the shapeoko for other purposes. It’s a lot of useful function for minimal development and support cost.


This is something we’ve been talking about.


When the Pro started shipping, I asked about feedhold on the FB “Unofficial” forum. After some discussion, and some pictures it was pretty clear to me that the F pin must be the same as the FH pin on previous boards.

For previous boards, I posted a DIY Pause Button and made a few for fellow FB group members. I was asked about making one for the Pro so I wanted to research how it could be accomplished.

I would not use a Shapeoko without one. I use it at least once in about 3 jobs.

Last time, it was to pause and lift the bit, and turn the router off so I could clear a bunch of masking film that was accumulating on the bit. Then, I just resumed. (to resume, you have to wait for the pause operation to complete, then push the FH button again, and the on screen buttons become available to resume.)

After I posted on the FB group, I was told by a C3D rep, that my request would be sent to tech support to get an answer… but no response.

As is posted here and in my request, it seems like a simple question for tech support. I don’t understand how company affiliated reps cannot provide this type of info on an in-production and delivered controller board. Some one at the company had to design the board and software (or at least spec it out to a vendor). Tech support should be able to provide a straightforward answer to a simple question.

Note: because FH is on the controller, it will work regardless of whether you use Carbide Motion, CNCJS, or other software.


What’s your question? All of this has been said here.
If you have the Pro controller, it’d be trivial to test.

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I have had a similar experience but it was just this old guy not being sure he had tightened the collet sufficiently after changing bits. I can verify the action of the pause button was as you described.

A useful feature that I was not aware of until I discovered it accidentally.

Thanks for your useful responses.




My question is:

Will C3D tech support CONFIRM that the F pin on the 8 pin Z connector of the Pro Controller Board is the FeedHold pin and would momentarily connecting that pin to the GND pin on the same connector (or GND on the BitZero or Bitsetter connector) work the same way it does on all other Shapeoko Boards (ie. cause the g-code to pause and lift the router)

A positive confirmation from C3D would mean that a FeedHold button could be connected to a Pro Controller Board without doing any damage to the board. Yes, it’s trivial to test it, but I would prefer to do so knowing that it will do no damage.

I agree that a lot of this HAS been said here, but no one that represents Carbide 3D has confirmed it.

I don’t have a Pro (yet) but the ability to connect a FH button would be an important factor in my decision to upgrade.