Last updated on November 2nd, 2018 at 12:22 pm
I bought myself a (chinese) CNC mill or an engraving machine respectively from ebay. It did not come with any assembly instruction rather than the ebay product images. So I decided to create this page on how to assemble the CNC 2417. I paid 260€ including the shipment plus an additional 42€ for customs.
This is what was shipped in the package:
- t-slot aluminum profiles
- t-slot aluminum working plates
- linear guides + linear bearings
- lead screws + ball bearings
- plastic (gray) and 3D-printed parts (black)
- AC adapter
- laseraxe controller board
- mini USB cable
- three stepper motors + cables
- router motor + cable
- lots of screws and nuts
- allen keys in four different sizes
I started with metal brackets, allen screws (short), t-nuts and the longest profiles to build the bottom frame. I aligned two profiles on the table and screwed them together. Then added the other two successively.
The next step was to assemble the working table. I used the two metal connectors (orange box) and four screws (short) and nuts to connect the two working plates. Do not place them where I did first as the allen screws will be in the way of the linear guides. Just place them close to the edges.
The linear bearings are simply plugged into the holes and fastened with regular screws (short).
For me the screws actually did not have much effect. I was still able to pull the bearings out. Maybe I will replace the screws with a larger diameter later. Guess what, there are screws with a bigger diameter in the package. How could I oversee them?! After I exchanged the screws the linear bearings could not be pulled out any more. This also had the side effect that the machine makes a bit less noise while moving.
Now, the lead screw nut can be mounted with
four of the regular screws. Actually, two lead screw nuts, two springs, and two of the long allen screws are supposed to form something like an anti backlash nut. I discovered this fact after I built the mill so I had to exchange all nuts with the anti backlash version. I was asking myself more than once why they would pack three spare nuts. Now I know… Keep that in mind for the other nuts. They have to assembled in the same way although it can not be seen in the pictures.
Afterwards, the lead screw (longest) and the linear guides (two longest ones) for the Y-Axis can be inserted. Now you can see that I relocated the working plate connectors more to the outside.
Time to mount the first stepper motor and the bearing for the lead screw. The bearing has a locking screw on one side. Make sure it is oriented to the working table. There is a notch through which it can be tightened. When everything is in place the working table should already move if you turn the spindle.
Now the frame is connected to the working table with six allen screws. Notice, that the side with the motor is located on the inside of the frame while the side with the bearing is located on the outside. As you can probably see I was not able to mount the black knobs on the lead screw because it was a bit to short. If you pull the lead screw or the stepper motor axis a bit out of the blue connector it is probably possible.
After attaching the working table to the frame I thought it might have been better to mount the outer plastic pieces first and push the linear guides and lead screw through the linear bearings of the working table afterwards. However, it worked…
The columns for the X-axis are built of the four short aluminum profiles, eight brackets, two plastic pieces, eight short allen screws + nuts, and eight long allen screws + nuts. To get a good alignment of the brackets I placed them on another profile before tightening the screws. You can not align them on the table because the brackets have a little ridge to center in the profiles.
According to the ebay images, the two linear guides should be above the lead screw mounting and the notches point to the back of the machine.
The columns are now connected to the frame with eight allen screws. I only tightened them so that I could still move them on the frame because the are not yet aligned. Afterwards the remaining aluminum profile and two metal brackets connect the two columns. I found out that a good spot to place them is 5cm from the inner back side of the frame as shown in the pictures. Then I tightened the screws and attached the next stepper motor with four long allen screw and the bearing to the plastic sides.
Before inserting the three linear guides and the lead screw, the motor mounting has to be built. It mainly consists of the three black 3D-printed parts with some bearings. The bearings are not screwed in any way because the fit very tightly. I had to push the large housing onto the table to fully bring them into place. The nut can now be screwed through the remaining hole.
The printed bridge-like part is for mounting the Z-Axis stepper motor. The ebay images showed, that only this one is connected with some plastic washers. Again, use four of the long allen screws to attach this motor.
The Z-Axis is built from the two smaller and shorter linear guides and the small lead screw and the motor clamp. Insert the four small linear bearings into the clamp and add the nut. Now you can push the linear guides through the holes of the outer housing and the linear bearings. I could not find any screws to secure them but it does not really seem necessary.
I connected the lead screw to the motor shaft and inserted the last and smaller ball bearing into the lower hole. There is a metal ring to be fastened to the lead screw so the bearing does not fall off.
Time to complete the X-Axis. This should be straight forward. Push the three remaining linear guides through the plastic sides and the motor mounting. Add the lead screw and connect it to the motor shaft and tighten the screws of the ball bearing. Unfortunately but again, when you completely insert the lead screw into the connection it will not be long enough for holding the black rotary knob.
Before mounting the motor make sure that the clamp is really opened. In my case so residues from the 3D-print prevented it from opening. I had to break it open with a screw driver and mild force. The first image shows how it should look like afterwards. Now you can insert the motor with the black printed ring. First, I placed the motor as high as possible but later had to lower it. Otherwise the cutter would have never reached the working table – even with a wooden plate on top.
The controller board is mounted with only three t-nuts and the spacers. In the end I only used two of them because I dismounted and mounted the board a couple of times.
After the cables are connected, the mill should work. Don’t mind the “Probe” pin for the moment. Do not connect the milling motor to the top right connector as it is shown in some of the ebay pictures. Nothing really bad will happen but the motor starts running as soon as you turn on the power supply and can not be stopped or adjusted by the controller. Furthermore, it runs in the wrong direction.
Optional: end stops
Thanks to my colleague who had a few end stop switches lying around I decided to add them to my mill. Practically, the Laseraxe board has connectors for end stops. The connectors are JST XH connectors with a 2.54 mm pitch. I bought a set of connectors and the according micro pliers from Engineer (PA-09). I also managed to crimp some connectors with regular pliers but I had to solder the cable to the connector to ensure they would not detach.
The Y-axis end stop is the easiest to mount. Drill one hole into the plastic next to the y-axis stepper motor, mount the switch and drill again through the remaining hole. I used some remaining screws that came with the mill.
The X-axis end stop is pretty much the same except that the motor carriage will not reach the switch before the spindle mount hits the aluminum profile. As you can see in the images I used two washers and a screw to extend the carriage a bit.
The only switch that I did not mount with two screws due to lack of space is the Z-axis end stop. I reused the hole that is used to keep the linear guide in place and. There is no need to tighten the screw stronger than before as the forces that impact on the switch are quite low.
When the switches are mounted some parameters for the GRBL firmware have to be changed.
- $20 (Soft limits): true
- $21 (Hard limits): false
- $22 (Homing cycle): true
- $23 (Homing direction invert): 3
You may be wondering why I did not enable the hard limits. I encountered random hard limit faults as soon as the spindle motor ran. As far as I can tell this should be an electromagnetic compatibility (EMC) problem due to the brush sparking. However, the soft limits work in both directions.
The value 3 for parameter $23 inverts the X- and Y- axis direction for homing. The default case is to seek in positive direction but my X- and Y- limit switches are mounted at the zero position.