Drag Chains and Wiring

Last Update: 11 November 2019

Parts needed:

  • 1000mm drag chains (x2)
  • 3D printed drag chain foot
  • M4-16mm bolt (x7)
  • M4 nylock nut (x6)
  • M8-16mm bolt (x2)
  • Motor wires (x4)

We will now be installing the drag chains; these contain and guide the wires on the LongMill so that they aren’t in the way during cutting. They also keep wires from wearing out from bending or being cinched around corners.

As mentioned previously, the chains can be found in the lighter long box (pictured). They come with detachable links so that you can adjust their length depending on the size of your LongMill. You can save these links for later when you upgrade to a larger LongMill if you have the 12×12 or 12×30 versions.

We’ll first start by removing the end connector links from both drag chains. You can either pull or squeeze off the connector as shown in the photos. A flat head screwdriver or thin shim can also be handy for this, just be careful not to cut yourself in the process.

For the pin-type end link, squeeze the two sides of the link together, then twist and pull to disconnect
For the hole-type end link, pull on one side of the link then twist it away to separate it

Do this for all four end pieces, two hole-types and two pin types, and set them aside.

We will attach these links to the machine, starting with the drag chain foot you set aside in the last step. It can be identified by its lightning bolt shape and the nut catches and wire clips it has on its back side. Also locate the small bag containing smaller bolts and nuts, as these will be used to attach the links in the following steps.

Use a pair of bolts and nuts to secure the hole-type end link onto the drag chain foot in the orientation shown by using a size 3 Allen key. The nuts should fit into the hexagonal cutouts underneath the mounting point, meaning a wrench won’t be needed.

This last foot can now be attached to the Y-axis rails in the vacant space on the left side of the machine. Use two of the short M8 bolts to fasten it to the rail, similar to how all the other feet have been mounted.

Drag chain foot mounted in place

Now get a pin-type end link (pictured) to mount the other end of the drag chain. This one will attach the the X-axis clip-on mount where there’s a slot for the two bolts to fit through. Use pliers or a 7mm wrench to hold the nuts from the top while you fasten the bolts from underneath with a size 3 Allen key.

On the back-left side of the X-axis rail, you’ll find a hole to secure another drag chain link. You should only need one bolt to secure the pin-type end link using the tapped hole, but if your hole is not tapped, use an M4 nylock nut on the other side to secure the part.

Find the hole on the X-axis rail to secure the drag chain link
Use an M4 nylock nut on the other side of the aluminum angle if needed

Lastly, we’ll attach the final drag chain end link onto the plastic ‘arm’ of the Z-axis mount using another pair of M4 bolts and nuts. Note the direction the link is facing before installing it.

Link fastened into place

Next, we’ll be removing a couple of links on the drag chain. To do this, put your hands on either side of the link you want to break, then twist and pull them apart to disconnect. Set aside the remaining, unused links for later; they can come in use if you’re planning on upgrading to a larger sized LongMill later.

12x12

On the 12×12 LongMill, both chains need to be shortened to about 24 links long. This is a little over half the length of the existing drag chains so it’s easiest to just fold it in half and add a couple links onto the halfway point.

 

12x30

On the 12×30 LongMill, only the Y-axis drag chain needs to be shortened to about 24 links long. This is a little over half the length of the existing drag chain so it’s easiest to just fold it in half and add a couple links onto the halfway point.

 

30x30

In the case of a 30×30 machine, we will remove 15 links off of the Y-axis drag chain, and none off of the X-axis drag chain. This will make it the correct length to mount at both ends when re-attached. Make sure to keep track of which chain is the shorter one so that you can re-attached them onto the correct axes.

 

Use both hands to twist and disconnect the drag chain links.

We’ll then start to unclip the tabs that hold the wires in the drag chain (pictured). These tabs are designed with clips on both side so that they can be removed to allow you to insert and remove wiring inside the drag chain. The clips on the tabs are quite strong, so sliding a flat head screwdriver or a long Allen key into the drag chain and using them as leverage to pop the tabs open works quite well.

One quick note, if you plan on adding more wiring into the drag chains in the future, it’s worthwhile to permanently remove every other cover tab since the wire will still be held in just as well but opening and closing them will take half the time. You can stick the extras into a baggy to save for later if you wish.

Unclip the tabs on the drag chain
All of the tabs unclipped and ready for wiring

At this stage, it’s a good idea to grab the router you’ll be using with your machine. We’ll show these steps using the Makita RT0700 / RT0701 trim router that we recommend. Also, grab the paper-wrapped motor wires while you’re at it.

Get your router and motor wires to start wiring the machine

To mount your router, simply loosen off the two front bolts until you can fit the router in the mount, then tighten back up again to secure it. You can adjust the height later if needed.

We recommend going back and forth between the two bolts to keep them parallel; and make sure not to over-tighten them. If you do over-tighten these bolts and start to strip the bolt head, these bolts can be substituted with the M5 bolts that came with your machine if you have any extras. It’s also best to face your router power cable towards the right side (pictured) since the dust shoe hose port sticks up on the left side of the router mount.

Mount your router with the power cable facing right

Grab a motor cable and connect it to the Z-axis NEMA 23 motor.

Grab the drag chain for the X-axis (the longer one for the 30×30) and seat the Z-axis motor and the router wire into the drag chain. Make sure that you have the correct end of the drag chain (with a pin-type link) so that you’ll be able to connect it to the mounted end link (pictured), and so that the drag chain can bend in the right direction against the X-axis. You can start to re-clip the tabs in place.

Clip the end of the drag chain to the end link on the Z-axis mount
Clip the end of the drag chain to the end link on the Z-axis mount

Swing the drag chain and clip it onto the end link attached to the X-axis rail. Pull the wires through.

Clip the drag chain onto the end link on the X-axis rail

Now attach a motor cable onto the X-axis NEMA 23 stepper motor.

We will take the cable from the X-axis NEMA 23 stepper motor and the Z-axis NEMA 23 stepper motor, as well as the router cable and insert it into the Y-axis drag chain. Clip the tabs in to secure the wires, and make sure that the drag chain is facing the right direction (with the hole-type link, pictured) to fit into the correct end links.

Grab the Y-axis drag chain and insert the X and Z-axis motor cables and router cable

Clip the both ends of the drag chain into the previously mounted end links on the Y-gantry and the drag chain foot.

Clip-in the drag chain here.

And here.

Now plug in the cables for the motors on the two Y-axis NEMA 23 stepper motors.

Connect the cables for the two Y-axis motors.

Bring the cables around to the left of the machine and slot them into the wiring cutouts in the drag chain foot.

Shimmy the Y-axis NEMA 23 stepper motor cables into the two guides in the 3D printed foot.

With all of the wiring coming in from the left, he machine wiring should now be complete.

All of the wiring complete.