Table Mounting

Last Update: 2 September 2020


The LongMill is designed to be mounted to a flat surface which is provided by the user. This could be as simple as a single sheet of material, or as intricate as a multi-piece torsion table with t-tracks and threaded inserts. One thing is to ensure that you’ve got a flat sheet (or multiple flat sheets) of material within the cutting area of the machine. This “wasteboard” area is where the material you will cut will sit on and serves to be cut into and replaced when needed.

We do not ship LongMills with a wasteboard because:

  1. It saves the cost for shipping. For example, a 4ftx4ft piece of 3/4” MDF shipped often costs over a hundred dollars in shipping and is very easy to damage during transit. You can usually find a full 4ftx8ft sheet of 3/4” MDF for under $60 at your local lumber or hardware store.
  2. Users can choose the size and material of the wasteboard to match their needs.


Suitable wasteboard materials

The easiest setup that we recommend is a flat, clean piece of 3/4” MDF to act as your mounting surface and your wasteboard. This is because 3/4” MDF is quite stiff and is readily accessible in 4’x4’ and 2’x2’ sizes from most big- box hardware stores or a lumber store. Any similar piece of thick, flat material would also suffice; you can choose at your own discretion. If you’re looking for more of a flashy setup, you can check out some of our community members’ table/wasteboard builds here for inspiration:


Machine Dimensions

When getting ready to mount your LongMill, the most important dimensions you’ll need to know are the size of its foot base and the total outline of the machine. As long as your mounting surface is at least the size of the foot base and you’ve left enough space around your mounting surface to account for the total machine outline, then your setup will be suitable.


The control box is also something you should plan for, as the design of the machine favours placing the control box on the left side of the machine whether it’s sitting on the table or mounted to the side or underside of the surface. The control box has buttons on the top which can Play, Pause, and Stop the machine’s motion so it’s a good idea to keep it mounted near your CNC. It also has a USB input on the left side, motor and other outputs on the right side, and the power input on the back side, so make sure to keep some space around it for cable management.


Generally, the sizes of each model of the LongMill have been designed to fit on the following surfaces as follows:

  • LongMill 12×12: Fits on a 2ft x 2ft surface
  • LongMill 12×30: Fits on a 2ft x 4ft surface
  • LongMill 30×30: Fits on a 4ft x 4ft surface

The diagrams below shows a more detailed view of each of the important dimensions. Note that:

  1. The red area inside the main box shows the cutting area as an offset from the foot base
  2. The blue area outside the main box shows the hanging parts as an offset from the foot base which makes up the total machine outline
  3. The area taken up by the control box isn’t accounted for in this diagram
  4. If you have our dust shoe attached, your cutting area in the X-dimension will be shrunk by approximately 50mm (about 22.5mm off the left side and 27.5mm off the right side)
  5. The width of the foot area is determined by the distance between the middle feet (not the front and back feet) since the middle feet sit slightly wider than the front and back feet do
  6. The red cutting area is based about the center-point of the router, thus you can plane an area larger than what’s stated if you’re using a large surfacing bit (add your bit diameter to the width and depth of the cutting area to find the maximum)
  7. These diagrams have got a small buffer on the cutting area (i.e. it’s been shrunkened slightly) since each part has its own manufacturing tolerance and can come together differently in assembly so we want to ensure we’re providing a reasonable guarantee on what can be expected from your machine
  8. Although the working height of the LongMill is approximately 350mm, if you’re planning an enclosure then we’d recommend having a height of 500mm at the minimum to ensure enough space for hose management, manipulating cutting material, etc.











Mounting your LongMill

To ensure that your machine is mounted securely and accurately, we’ve created a series of steps to help you do so. We highly recommend following these steps exactly, as the order of these steps matter. You’ll need a computer to be connected to the machine in order to align it properly.

We will start by checking the tension of the Delrin v-wheels. As we did in the previous steps, we want to make sure that the wheels barely turn with our fingers by adjusting the eccentric nuts.

We will also properly tension the Delrin anti-backlash nuts. Turn the tensioning screw a little bit at a time. Check for play by moving the gantry back and forth and seeing if there is any excess movement. Do not over tighten, usually a half turn is more than enough.

Gently put your LongMill on the mounting surface and shuffle it over roughly where you want it. In this case we’re using a 4’x4’ MDF sheet as a combination mounting surface and wasteboard which we had cut to 42 inches to better fit in a car. We’ll be mounting it in the middle and have the electronics box sit off the material to the side.

Move the machine onto your mounting surface. Position it to where you want it.

Once positioned, start by moving the machine all the way to the rearmost position by jogging in the y-axis on your control software. Keep moving backwards until you hear a grinding coming from the motors on both sides; this is to confirm that your machine is all the way back and it aligns the left-side feet to the right-side feet.

Move the machine to the very back until it stalls.

We’ll start by mounting the right side of the machine. Using a drill with a long Robertson driver or a short one on a bit extender works best for driving in the screws so that you have the necessary reach. You can use the particle board screws provided, or use your own mounting hardware depending on your material or its thickness, but please ensure that you don’t use counter-sunk wood screws to attach the feet as this will crack them.

The screws included are 1-1/4”, 1-1/2”, and 2” size #8 particle board screws. Each foot has two holes for mounting where the shortest screws are meant for the inside and the longer one are for the outside. Please note that the 2” screws WILL go through 3/4” MDF, but were still included since they can hold the LongMill feet down better. If you choose to use them, make sure that the surface under the board will not be damaged if you have screws coming out the bottom.

Alright, begin by moving the machine a couple of inches forward and mount the inside of the top and bottom feet using two wood screws (1-1/4”).


Next, we’ll put screws in the other two spots on the same side, this time on the middle feet.


Now fasten the diagonal mounting points of all the right-side feet using the longer screws.


At this point, one side of your machine will be fully secure. The technique to make sure the other side is mounted parallel to the first side is by running the gantry between its limits and mounting the other side as you move it along the length. Start by mounting the top left foot on the inside:


Move the machine down so that it is roughly in the middle of it’s length, then secure the insides of the next two feet:


Finally, move it to the front and secure the inside of the front left foot:


Now move the machine again to the middle spot and use the longer screws to finish mounting the feet using their diagonal mounting holes.


Your machine should now be fully secure to its mounting surface. From this point, you should be ready to get cutting your first jobs! If you’ve got the touch plate or the dust shoe add-ons alongside your machine, you can see our pages on how to get those assembled and set up:

You can also navigate to the Post-Build section of the LongMill resources (the next page) if you’d like to try out one of our easy starter projects, learn how to maintain your machine, or would like to address some issues you had during setup by visiting the page on ‘Common Issues & Fixes’.