Bests & Worsts Reviews from Amazon

This is a great starter machine and at reasonable cost for its size if you would like to engrave on wood or other soft materials. It is made of wood and precision suffers a lot because of the Z axis assembly that does not align with the Z axis shaft perfectly (more about this below) and because the whole router assembly flexes on the gantry. I checked to see if I did not tighten the tension rollers but that is not the problem. The rollers have some (very small) play on the rods that I cannot correct. The result is that when I send a set of commands in a G-Code file (more on this below) that will cut a square on acrylic by cutting 0.05 of an inch deep at 5 inches per minute (which is a very slow speed) , the corners are not perfectly 90 degrees because the router is not perfectly perpendicular when it changes direction due to the flex (more on accuracy below). If you are still interested in purchasing this machine, here is some info you may find useful but grab your coffee and get comfortable because this is going to be long. Assembly: Assembly took about 8 hours but don’t let that scare you at all. You will need a tabletop space of at least 35”x 35”. Almost all pieces are drilled in a way that you do not have to worry about left or right side so you should put all identical pieces together before you start. The only tools needed are a phillips screw driver, needle nose pliers and wire cutters. The assembly instructions posted on the Internet as a PDF at BobsCNC are most likely the best you have seen for a machine that comes in so many pieces. Use a tablet or a laptop to read the PDF from the screen instead of printing it. Follow the instructions and the pictures and you will find that there is not much there that leaves room for questions. During assembly, at no time I needed a second pair of hands or had to read a step twice because it was not clear. However, I found that you should pay attention to the following: 1) The wires connected to the switches cannot take much abuse and if you twist them enough, you will have to re-solder them to the switch. But once switches are mounted and the wires are wrapped and tie wrapped, they will not move any longer and this will be no problem. 2) There are 3 switches, 2 have the same length of wire and the third that goes all the way up by the Z axis motor has a much longer wire. Not sure if one of the other 2 switches should have a little longer wire and I got the wrong part but the wire from the X1 switch was too short and barely reaching the microcontroller when stretched so I had to extend it in order to wrap it nicely and route it alongside the other wires from the X1 side. 3) The Z axis motor and rod coupler is cut in a spiral to avoid off center movement but that does not help enough as I am unable to align the Z motor shaft with the Z threaded rod perfectly and you can see the motor (and a little the router) move back and forth while the router is moving up and down. That is very annoying and I believe that it can even affect accuracy (on deep cuts) since the router is slightly oscillating while it is moving up and down. Before you power up the CNC, make sure that the coupler does not show any uneven gaps in the spiral cut to avoid shaking too much. 4) In the assembly instructions pay extra attention to section 2 (Y Carriage Assembly) step 7 in page 14. There are 2 pieces that hold the belt ends on the back of the router assembly that you should make sure that the “teeth” cuts are on the upper side. If you put these on wrong, you will have hard time correcting them after the router assembly is mounted on the rails and you are about to put the belt on. 5) In page 54, it shows how to connect the stepper motors and switches. X2 will be the motor on the left side as you are looking at the machine from the back. On that side there are 2 motors, this is the one that is exactly opposite to X1. If you cross connect the X1 and X2, when later you “Home” the machine, the gantry assembly will run the opposite direction and there will be no switch there to stop it which will result in damage to the belts. If you see the gantry running away from home (Home is where the switches are mounted) you should unplug the USB cable from the computer to stop it before it reaches the end. 6) The spoil board I received was not square. As a result, I could not follow the instruction 9.4 on page 52. I contacted BobsCNC by sending a message via their website and got an answer via email within 1 hour on a Saturday. In the end I was told that they would send me a new board if I wanted but I was able to square put the board on squared to the machine frame so I am good for now. Yet, I was told that they do not cut the boards with a CNC and they only use a CNC to make the holes in it. This means that others may end up having the same issue. After assembly, you realize immediately that this machine needs plenty of space. I purchased a DeWalt stand and mounted a 36” by 36” tabletop on it. Then I made aluminum brackets that hold the router in place and mounted the laptop on an arm. Here are the main items I purchased among with some other minor things from a local hardware store. I used L shaped aluminum bars so I can lower the E2 CNC on them and held it tight in place while I can anytime just lift it off the table without the need of any tools. Also note that I routed the cabling away from the "Home" side of the router and made a small L shaped bracket out of aluminum to mount the power supply in a way that I can see the power light (see pictures). Finally, I used a spiral power cord and wrapped that around the router cable. Under the tabletop I mounted a power strip where I plugged in everything including a shop vac. DEWALT DW7350 Planer Stand with Integrated Mobile Base Rectangular Table Top with Black or Mahogany Reversible Laminate Top (Top Only) 36" x 36" 31177BP Key Locking Laptop Security Stand, Battery Pack Compatible Software: If you are new to CNC, here is how it works in a few words. You need 2 pieces of software: 1) You need an application that will allow you to design or import images of your designs so it can generate a G-Code file. Typically you would install this application on your desktop computer so you can design what you need to engrave or cut. There is plenty of software that will allow you to import your designs and some is free. The recommended F-Engrave works well for engraving but was not able to find an easy way for cutting although there may be a way and I am not familiar enough with it. I also found that F-Engrave has what seems to be a bug when I set the V-Carve to a straight cutter bit. The produced G-Code file for a square cut comes up empty. If you have more than just engraving in mind, you should really consider Fusion 360 which is cloud based and you can get a Hobbyist license for a year free with the ability to further renew also for free. If you learn how to design and machine objects in Fusion 360, you can handle any CNC project that comes to mind. The full version of Fusion 360 currently costs $300.00 per year and you will have to pay for that if you are not a start up or a hobbyist and your company makes more than $100,000 per year. 2) You need an application that will read the G-Code and send commands to the CNC machine. Typically you would install this on a laptop that you will plug the E3 USB interface to so you can have it by the CNC machine. A G-Code file contains simple commands in plain text that are nothing more than distance and direction commands telling the router which way to move. The suggested software that sends the commands to the CNC machine is UGS (Universal G-Code Sender) which is free and works well. NOTE: If you are going to use a laptop with a touch pad, you should disable the “Tap to Click” function from the touch pad properties because once you bring the Z axis to the desired “Zero” position, you may accidentally “Click” on more “Z-“ while moving the cursor away from the button and that will send the router right in your work piece. Accuracy: To elaborate on the bad accuracy of this CNC, consider the following G-Code that cuts a square 4" x 4". In this case while I am cutting 1/4 inch thick acrylic, when the router gets the command to change direction the cutter bit is not all the way to the edge due to the flex of the router and that results to a square with rounded and not 90 degree corners. Although the fault is about 0.05" to 0.1" it is significant if you consider a simple exercise as to cut 6 of these squares and then glue them with acrylic glue together to form a box. It will be impossible to form an "air tight" box even if you manage to put the pieces together in a way that the edges will meet enough to be glued. Even then, your box will not be a normal cube but more of a trapezoid cube that is easily identified as such by the naked eye. G90 (Absolute positioning) G20 (Values are in inches) G17 (XY selection) F5.00 (When the command is "G1" the speed of the movement, a.k.a "Feed Rate", will be 5" per minute) G0 Z0.0500 (Raise the Z axis 0.05" above zero, a.k.a "Z Safe") G0 X-2.0000 Y-2.0000 (Move X and Y to the lower left corner) G1 Z-0.0300 (Lower the Z axis 0.03" under the surface so the rest of the commands cut 0.03" deep) G1 Y2.0000 (Move Y to the upper left corner) G1 X2.0000 (Move X to the upper right corner) G1 Y-2.0000 (Move Y to the lower right corner) G1 X-2.0000 (Move X to the lower left corner which is the starting point) G1 Z-0.0600 (Move Z axis deeper to 0.06") ...The rest should repeat the same commands until the square is cut as deep as the thickness of the material Now, I found that the square comes out better if I write G-Code that cuts 4 straight lines lifting the Z axis at the end of each line but it is still slightly off square. I believe that the problem is with the following 3 factors: 1) The flex that exists because there is no meaningful way to tension the rollers on the bars. Even worst, the nuts of the adjustable rollers will dig in the wood and make a place for them that they tend to fall in every time you try to tension. Even if you manage to tension this machine correctly when you first put it together, as I did, it is inevitable that in the future you will need to re-tension the rollers but that will be very, very difficult to do. 2) The gantry does not sit perpendicularly to the X axis and that results in trapezoids. You can tell that it is off (if it is off on yours) by pushing the X axis all the way home and you will find that one side reaches the home before the other. To compensate for that, I push the gantry (X axis) tight to home and then power on the laptop which locks the motors and keeps the gantry squared. Even then, there was still a problem and I had to put a filler between the "home wall" and the gantry on one side because it was still off by 0.03". 3) No matter how much you tighten the rollers and the belts, you will not be able to stop all the flex due to the fact that this unit is made out of wood. ***Update 11/23/2017: I was finally able to cut perfect squares and circles on acrylic using these SHINA Titanium Coat Carbide End Mill Engraving Bits. These cutters are very sharp and cut acrylic without putting too much pressure on the router and the gantry. Still, I had to cut in 0.0300 increments and feed rate of 10 inches per minute which takes a lot of time for such a simple task*** So, if you want this machine to engrave words and shapes on wood, it may serve you well. If you need it like me to make precision cuts and precision engraving on acrylic or harder material, you should look elsewhere. Be aware that although you may be allowed to return this machine, they expect that you will disassemble it and re-pack it in its original condition which I think will take you another 8 hours to do. And since at the time of this review this is not a Prime item, you may have to pay to ship it back (Not clear on this).