Where to locate limit switches?

If anyone has added true limit switches (as opposed to just home switches), where have you located them?

I’ve considered drilling suitable holes on the X-carriage and Y plates at the opposite sides to the existing home switch locations i.e. at the rear of the Y plate and the right hand side of the X carriage extrusion, to mount the extra micro switches.
As I have to disassemble my X-Carve to add the home switch activators anyway, it seems like a good time to drill and tap any extra holes.

Why do you think you have to take your machine apart to add the homing switches?

Now is a good time to add the “actuators” for the limit switches. Start with the X-Axis limit switch actuator. Push the post assembly insertion nut into the rear piece of X-Axis Makerslide

You can mount the switches and the actuators after the machine is assembled.

As I understand, there is too much electronic noise to use hard limits without additional modifications to the system (filters, etc) with the standard setup. It might be possible with the X-Controller, they have added additional filtering. The excessive electrical noise will trigger false positives in the limit switches, if I’m recalling correctly from other postings. Some people HAVE made it work, though, so it’s not impossible.

@LarryM I don’t have any post assembly nuts, I didn’t get my X-Carve from Inventables.
@DanBrown I’m running a Gecko G540 controller with Linuxcnc, not Arduino based.

Sorry, should have provided more details in original post. See this thread about my machine.


I’m trying to look on the bright side. :grinning: If I have to pull things apart to add the captive nuts, I may as well drill holes for limit switches as the same time. Of course of someone has some neat idea for mounting limit switches, that would be good too,

My x-carve is on the way, and I was thinking of adding true limit switches to protect my investment from a cannibalistic episode. My thoughts on this subject are that if a hard switch & relay is used, instead of a software solution, then noise won’t be a problem. so if any of the limit switches are tripped, all power to the steppers and spindle is cut via the relay.

Seems like that could be entirely possible, just make an external control unit that the entire X-carve would plug into and would be totally separate, just cutting power to the entire controller assembly if it limited out…

You could take some rubber cement and lightly glue the captive nut to a thin strip of wood like a popsicle stick or tongue depressor. Then you could slide it into the gap and start the screw into the nut, then just pull the stick out of the gap. Needle nose pliers could hold the nut while you tighten it up. Doesn’t have to be that tight, use Loctite to hold it.

Does Mach3 or LinuxCNC do soft limits? Soft limits can be very effective.

Soft limits are supported by Linuxcnc and I will use them if I must but as I said, I have at least partially disassemble the X-Carve to get the home switch actuators in, I may as well do any other changes I need while it’s in that state. The X axis stiffening mod is one I’d like to do but not ready for that yet.

As you say, since you already have it apart might as well make the changes.

I prefer soft limits over hard limits as the soft limit occurs before the movement, hard limits are after the fact.