Adding Limit Switches

Hi all,
I want to add limit switches to my X50 and I noticed that it came with some bolts that I can’t see any function for. I am hoping someone can support my idea of using them to mount the limit switches.
They appear on all of the mounts in the right place, so . . . . . . (see pic)

The BOB has connections to wire them up and they are listed but I have not seen anyone else show them fitted. Is the software to use them in the 1F controller?
I’m a belt-and-braces type, I like the idea of limit switches okay?

Above is a picture of the bolts I am referring to. Note also my home made drag chain fittings. My machine is not quite ready to run but it is close. It has a HuangYang VFD and water cooled spindle.

I think that may be atramming bolt.

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Hey Greg,

I would not touch that bolt unless you want to adjust the tilting of the rails.

Retrofit proximity sensors (here: inductive sensors) as limits switches are shown here (including 3D-print files) and here.

Stall homing is explained here, the datasheet of inductive proximity sensor Omron E2B is here.


Thanks Aiph5u, I won’t be adjusting them just now. I will make my own mounts elsewhere.

This looks like a simple solution but the ID of the clamp would need to be made larger for the Onefinity.

The Buildbotics forums have several posts about limit switches too

Thanks for the posts folks. I have purchased some small reed switches encased in protective casings that I hope to use as limit switches (see pic). I will make my own brackets for them and use small magnets to trigger them. Let me know what you think of this idea.

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Hey GregZo,

reed switches are hermetically enclosed in glass cylinders so are dust-tight, not subject to corrosion and maintenance-free. However, unlike inductive proximity sensors (e.g. Omron E2B), it seems their life is not endless:


The mechanical motion of the reeds is below the fatigue limit of the materials, so the reeds do not break due to fatigue. Wear and life are almost entirely dependent on the electrical load’s effect on the contacts along with the properties of the specific reed switch used. Contact surface wear occurs only when the switch contacts open or close. Because of this, manufacturers rate life in number of operations rather than hours or years. In general, higher voltages and higher currents cause faster wear and shorter life. Depending on the electrical load, life can be in the range of thousands of operations or billions of operations.

– Source: Reed switch – Wikipedia

Reed switches still have mechanical contacts, photoelectric sensors like on the Onefinity Elite Series or inductive proximity sensors not, so only the latter two have really infinite life.

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Hey thanks Aiphu5u,
Next part- question: Here is a photo of the carriage and it has these two M5 bolt holes that are empty and don’t seem to do anything. I want to mount my limit switch magnets on them.
Will this work? It looks like it will be fine but I’m asking just in case.

Hey Gregzo,

in these holes you find the grub screws that hold the linear bearings in place. You can put short bolts on top of them, but I would measure the depth of the hole to the grub screw beforehand so it doesn’t reach it.

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Great, thankyou very much !

I did the same thing to mount the trigger half of my proximity sensors.


That’s correct, those are tramming bolts for the router.