Introduction: Limit Swith Mount for CNC's

Ever bought those CNC limit switches from ebay and have no clue how to mount them to your CNC? Check out my design for ideas or design your own.

My design allows for a large number of configurations or orientations of mounting the limit switches to the mount board. The mount board also can be broken into smaller pieces in case of any constraint issues with the CNC.

Step 1: Buy Acrylic, Limit Switches, and Hardware

First step is to buy:

  1. 1/8" (0.118") acrylic sheet.
  2. Limit switches
  3. 4-40 x 1/2" machine screws, two per switch

The 1/2" screws are exactly the right length to mount the limit switches to the acrylic mount. If you get longer or shorter, I doubt that it'll work.

Also consider buying whatever screws you need to mount the mount board to the CNC if you don't have them already.

Step 2: Design

Use your favorite 2D vector CAD software. I used autocad student, but draftsight and inkscape are two free software vector drafting softwares that can also get the job done.

In my design, see attached, you'll notice that there are 8 small holes capable of fitting the switches in many (>= 16) unique configurations. I also added two lines through the piece in case you need to break off portions of the mounting board for constraint reasons. The image here shows the final mount board with one of the edges broken off.

Step 3: Cut

Place the acrylic sheet in the your laser cutter and have it cut out as many mount boards as you need. If you don't have access to a laser cutter, look around for your local Maker Space.

Step 4: Mount

Using 4-40 x 1/2" screws, screw the switch to the board in your desired configuration. See the attached pictures for several unique configurations that I'm using on my CNC. The screw diameter and length are precisely design to tap into the plastic and not protrude beyond. Using the two larger holes, designed for M3 screws, attach it to your CNC. Ideally, you want the limit switch installed where it'll engage just before the CNC hits each of its 6 limits.

Comments

author
BeachsideHank (author)2016-09-07

Limit switches may seem like an afterthought, but in reality, they perform a function no less important than any other circuit control device and should be thought about at the earliest stages of design and build. Your rendition is a superb example of usefulness and universal adaption, well done!

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