Are Limit Switches Necessary

Is it really Necessary to Install and use the Limit Switches? I’m going to use VCarve Pro and My X-Carve and with so many complaints about them breaking and not working correct, I wonder.

They’re not Limit switch, just homing switches. If you want to choose your Home location on your work area every time manually, you don’t need them.


Whether the switches are necessary or not is a judgment call. There are some advantages to using the homing switches in conjunction with software features in Grbl.

I use VCarve Pro with my X-Carve and I have the homing switches active and use soft limits to prevent my machine from breaking the switches and to keep the spindle from hitting the sides.

As homing switches they are totally unnecessary as in my honest opinion, you should set zero to the stock you are cutting. As limit switches - they only work in one direction. Pointless as far as I am concerned. Plus, the wire is unshielded, susceptible to noise… yada yada.

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My question would be. What if you have a fixture mounted to your table to do several of the same part and they all need to be the same. Something happens during one of the operations and you loose steps. Now your machine is no longer where it should be.
If you have homing or reference switches install and configured correctly you can just reference the machine again. Move to your G54 work offset 0,0,0 put in new material and run another part. No mus no fuss, you don’t have to guess if you have your home position exactly where you want it to be.

These mechanical switches will not get you a consistent zero. If I am in that situation, I load up a v-bit, cut a divot at my desired 0,0. Then I can always get zero. The touchplate gives me z-zero between tools. Actually a touch plate can be configured to give you all three zeros in Mach3.

Otherwise, i would use IR sensors. Keep in mind, I am not using GRBL or Easel but I am pretty sure these could be configured on top of the GRBL framework.

I too will not be using Easel or GRBL. That is why I said configured correctly. My Mega-Carve will have full homing and limit switches with shielded wiring with no spindle power running in the same drag chain with limit switch wiring.
There are literally hundreds of ways to set up CNC machines.

complaints about them breaking and not working correct

This topic has been beaten to death on this forum. The problems that have been reported are due to the fact that the X-carve is just not set up to do the switches correctly.

Having said that, there are things that can be done to correct the deficiencies and get the switches to work correctly. The upgrades are not that expensive considering the price of the X-carve.

The X-carve is a good compromise between function and expense. It allows many people to have a CNC router that would not be able to afford one of the professional machines that costs thousands more.

Homing switches and limit switches add functionality to the machine. If you really don’t like what it takes to make them work then use a manual method and get on with the carving.

Some suggestions:

  1. use shielded wire for the homing/limit switches. Leave the shield un-connected at the switch end, ground the shield at the controller end.
    2)for the wire that runs to the spindle (300W unit from Inventables), use shielded wire in the drag chain, twist the wires coming from the spindle to make a twisted pair, if you still have noise put a 0.1 ufd capacitor with the appropriate voltage rating across the spindle motor leads (close to the motor). Ground the shield on the spindle shielded wiring at the controller end.
  2. for the most benefit with the least problems configure grbl to use homing and soft limits (not hard limits). By the way, this really works (haven’t tried it with Easel - your mileage may vary).

Happy carving!

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I started out using the homing switches. I soon discovered that with different material offsets they become pretty useless pretty quickly. But, I did make use of the bolts/slot nuts that come with the limit switch kit.

To borrow your example, if I had several of the same part to cut, I would set the machine to 0,0. Then set the bolts as hard stops for the machine. Between each piece cut the power and manually rack it to 0,0, set Z 0 and power back up for the next cut. Of course, neither soft nor hard homing will work for pieces with tool changes because the 0,0 you define is the 0,0 of the tool as well, not the center point of the tool. So your subsequent cut will be off by the difference between the radii of the two tools.