CNC routers are wonderful machines for cutting and shaping wood and other materials but sometimes there’s no choice but to use a router without computer control. For example, when trimming the edges of wood to size, or for using the router as a finisher with sanding drums. When that kind of work is needed I don’t want another machine: rather I want to use my CNC router for occasional manual feeding. To do that a fence is very useful, as it allows pieces of feedstock to be pushed past the tool/sander in a straight line. Not only can that help ensure edges are kept parallel, but it also allows creation of small mouldings with edge-shaping bits.
This 3D printing project is my attempt at creating a very simple fence system for my cheap Chinese CNC. The fence part simply slides into the groove along the top of the CNC bed, after light sanding to get a good fit that doesn’t wobble. However, for manual feeding we don’t want the fence to be able to move along the bed groove, so a part is included for a simple stop that can be used to prevent that happening. The stop connects to the side of the bed using a winged hold-down nut as shown in the photo below. You can download the 3D printing files by clicking here, including the OpenSCAD file for any adjustments you’d like to make.
Hopefully you won’t mind if I finish with a word of caution. But, using a CNC router for manual feeding of materials brings risks you may not be experienced with. Probably two of the main ones are the dangers of having hands near your tool/cutter (which can be avoided using a proper push/feed stick) and extra dangers of pieces of tools and feedstock breaking and flying away (which can be largely avoided by feeding slowly and wearing sensible clothes and eye protection).
Another rookie error is to feed material with the rotation of the tool, which means it could unexpectedly get pulled through and shoot out like a javelin (I did that on a router table years ago and it’s amazing how fast the expelled material can be). Not only is that dangerous: it can even ruin your work. You may also want to wear ear protection as the sound level will be higher working close to the motor and tool. Basically, please be very careful and don’t take chances using the 3D models provided here 🙂
This is a simple 3D printed design I came up with to extract smoke and fumes on my cheap Chinese CNC machine when LASER cutting. Basically it consists of a small collector to fit under the z-carriage (with a holder to glue onto the collector) and a couple of parts to adapt a PC fan to fit standard plastic hoses. The collector, once glued onto the holder, should fit the bottom of the z-carriage as shown in the photo above. It’s designed to be removable for when the CNC is used for routing. The z-carriage on my CNC seems a common design, so hopefully this should work on many CNC machines. The inlet and outlet parts need to be glued onto a 12V PC cooling-fan like in the photo below.
From the outlet I attached a 32mm plastic aquarium hose, the end of which goes out of a nearby window. Between the inlet and the collector I used a bit of 20mm rubbery plastic plumbing hose. Despite the design not being optimised for aerodynamic properties, it does remove most of the smell of smoke away through the window. It’s not perfect though as draughts can result in smoke not getting sucked away. I got around that by making a shield to go around the front and sides of the laser to help make sure smoke and fumes get into the collector. If you want to print your own you can get the 3D printing files by clicking here, including the OpenSCAD file in case you need to make any changes.
Sometimes it’s nice to make a video, even a timelapse one, of a project coming to fruition on a CNC machine. Maybe just as a keepsake, or to share, or even to make some educational Maker instructions. So being able to add a GoPro camera, or other camera that uses GoPro mounts, is something you may want. I did anyway, so the project shown above is a simple 3D printed mount that clips onto a 20mm-extrusion on the front frame of my CNC, which can be positioned right in-line with the work-bed centre.
It’s a very simple 3D printing project that doesn’t even need any support material, so shouldn’t be a challenge if you have access to a 3D printer. The files you can download from Thingiverse by clicking here, which include the OpenSCAD file in case you need to customise or adjust it. Once made you use it to fix on a sticky mount base like in the photo, for your camera arm to fit onto. And below is a photo of my GoPro session mounted on my CNC so you can get a better idea of how it works.
CNC machines have plenty of moving parts and if we want our routing and LASER cutting to be as good as possible the movements need to be as smooth and unrestricted as possible. When I built my cheap Chinese CNC it came with rigid shaft couplers for connecting the threaded lead screws to the stepper motors. That meant that the motor spindle and lead screw couldn’t be adjusted to be perfectly in-line, just because of tolerances in parts and mountings. So, for part of a full rotation the lead-screw was binding (i.e. becoming hard to turn) and the rest of the turn was fine.
If you find you get the same problem, you could just do what I did: change the rigid couplers for slightly flexible ones. In the photo below I’ve shown the difference between the two. The bottom one is the original rigid one and changing to the new one involved no more than loosening the grub-screws, moving the lead-screw to the side, then inserting the new coupler, pushing in the end of the lead-screw, and tightening the grub-screws. For just a few minutes work it made X and Y axis motions so much smoother. And, for only a few pounds/dollars per coupler it was a cheap job too.
20mm square extruded aluminium section is commonly used for cheap CNC routers, especially for kit versions. So I designed this very simple 3D printed part that clips over three edges of the section. I did that for two reasons, the first being that I wanted to use one with two of my frame-end feet 3D prints (click here to read more) to make a stable tri-point support to reduce vibrations when routing. Secondly though, it’s just a useful thing to have to glue to anything I want to fix onto the frame while still being able to remove it later (e.g. bit holders or cable tie down pads). If you’d like to 3D print your own, just click here to get the STL files on Thingiverse.
Many cheap CNC routers are based on 20mm square extruded aluminium frames, with slots and a hole running along them to attach fixtures. Often the four pieces of the frame at the bottom lie directly on the underlying surface, with no supports at the corners. That can be a problem as routing can cause a fair bit of vibration that can be transmitted straight into your work surface. If left unchecked, that can lead to annoying noise as the work surface and adjoined walls and floors vibrate with it. So, I designed this simple foot that can be slotted into the end of a 20mm extrusion that lifts it off the surface below, and which you can also use to add a small rubber or felt pad, further reducing noise and vibration. To get the STL files for 3D printing just click here.
It can be quite fiddly fixing down a routing or LASER cutting project onto the bed of a CNC router. It’s even harder if you also want to align the material to the edge of the bed so you can align cuts with existing clean edges, or because you’re doing work over a number of sessions. So to help me quickly place lined-up sheets of plastic or wood onto my CNC bed I designed the small edge fence shown in the image below. It has to be 3D printed but takes up only a small amount of plastic and simply slides into the groove on the front or back edge of the bed-plate as the photo above shows. If you want to have a go at making some just click here to get the STL file (and OpenSCAD file in case you want to customise it).
One of the downsides of buying a cheap CNC router is that you’re left to your own devices when it comes to the best ways to hold down thin sheet materials like wood and plastic. Lucky then that there are plenty of designs online for hold-downs to secure your workpiece when cutting or engraving. On this page I thought I’d introduce you to two of my designs: one for edges and one for corners, both of which can be customised, if you have the need and knowledge, using OpenSCAD. Of course, making them means you’ll need your own 3D printer, an amenable Maker acauaintance, or a willingness to pay for 3D printing online.
Firstly, here’s a photo of my edge hold-downs. They have a small step-out at the bottom to hold the sheet above the CNC bed, so cuts can fall downwards and valuable cutting tools can be kept away from the underlying metal surface. They also have a sloped vertical face to help ensure the sheet doesn’t get pulled upwards. They also have holes and slots so they can be fixed to the bed using standard bed-bolts or some suitably sized bolts and wing-nuts. Click here to visit the Thingiverse page to download STL files for 3D printing and the OpenSCAD file.
While the edge versions are very useful, sometimes we’d rather hold down corners, either instead or as well. So below is my design for corner hold-downs. They’re very similar to the above design, but have a right-angle end to restrain the sheet on both the X and Y axes simultaneously. As for the edges, there’s a version for fixed corner positions (with a bolt hole) as well as one for adjustable corner positions (with a bolt slot) so they work with a wide range of sheet dimensions. To get the STL and OpenSCAD files for these you can click here.