Limit switches triggering hard limit warning

I’m in the process of homing the machine for the first time, but when I trigger the limit switches by hand, rather than the x y or z lighting up at the bottom of cut control, I get a hard limit reached warning instead.

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Mine does that too. Will it home correctly?

Hopefully they fix these bug in the next version of CutControl.
My machine works perfectly. So I just deal with it for now. If its tiggering the hard limits they are working.

Yeah, it seems to home correctly. I’ll move forward then knowing its just a bug. Thanks.

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Go make something…

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Everything about the limit switches are infuriating.


i wonder how easy it would be to replace with proper proximity censors

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I’ve had similar thoughts… Replacing the mechanical limit switches with micrometer adjustment style inductive proximity sensors. I am completely unfamiliar with GRBL and if langmuir has made modifications to upstream for cut control features. It is very tempting to replace GRBL with LinuxCNC or reprap firmware.

I used them on my converted mini mill. They work just like a relay/switch, but they need power to them , (pretty sure it’s 5v) that you might be able to tap from one of the controllers.

I considered doing this myself, but turned out to have no issues with the stock switches in actual use.

I’ve had chips get stuck behind the lever arm twice. The first time was turning surfacing the base plate (I have barely used the machine). The Y1 and Y2 switches have slightly different activation and de-activation travel. The Y2 switch both activates at a longer distance and deactivates at a shorter distance than the Y1 switch. The Y2 switch has also, very oddly, managed to shift on the mounting screws and is obviously slightly diagonal now… shoulder bolts might be needed to hold them steady?

I have also had both of the adjustment distance studs rattle loose. The second time it happened was after I had reinstalled it with blue loctite (wtf?). I’ve also had the jam nuts come loose and loose calibration once on each side. There must be some pretty significant vibration in the Y axis carriages?

These are the proximity sensors on my lathe that can be set as a threading stop: Something similar should be workable for the MR-1.

These sensors are supposed to reject chips on the face, which sound ideal.

The repeatability is spec’d as better than 0.2mm, which appears to be better than average for sensors in the $100 price range but is worse than I’d like. Ideally, I’d like the repeatability to be around 0.025mm or 0.001".

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I’m taking really light cuts for most of my work, so just vibration from movement and the spindle, and I’m not throwing a lot of chips so no issues there currently… I’ve not seen any issues with anything coming loose.

I did some testing with repeatability of the switches after everybody was concerned with the type of switch used and posted the results to the Facebook group, here’s what I found:

“I tested 6x on each Y axis switch and found 0.0003” repeatability on both. (This could certainly change with wear)

It takes about 0.012" deviation from one Y axis carriage to the other to induce an alignment error of 0.001" per 3 inches of travel. So 0.0003" alignment error wouldn’t even be perceptible, as long as you set the switches accurately to begin with."

I’m not sure if proximity switches could match that accuracy, but if chips are a problem they would definitely help, and the overall loss in accuracy might be negligible.

finally setting up my limit switches and noticed something (that i am not sure will matter or not)
i have the 2 Y ones activated at the exact same time, easy, but when i back it off from the limit, they disengage at different distances, almost .005 difference. will that matter?

Mine was the same when I was dialing in y1 and y2. Won’t matter as far as I’ve experienced in normal operation. When it’s homing it ignores the backwards click for lack of a better term.


I have the exact same issue in that the reset travel is different. It shouldn’t be an issue in terms of homing the machine but it sure makes it difficult to get the stops dialed in.

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