Simple CNC fence for manual work

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.

The CNC fence in use

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 🙂

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A simple LASER extractor project

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.

The extractor fan pump with 3D printed parts and hoses

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Adding a shield to a CNC-mounted LASER module

My LASER is an attachment for my cheap Chinese 1610 CNC router so it isn’t tucked away inside a metal case with a tinted window. That means I have to wear LASER-safety glasses whenever it’s running, which can be annoying if I’ve got other things to do. So I designed this simple 3D printed shield with dark red windows (as the LASER is blue). It comprises a small frame that slips onto the LASER module (with a hole for a screw if needed to stop it sliding down) and a three-sided shield that slides onto the edge of the frame, as shown below.

3D view of the laser shield assembly

After 3D printing the front and two sides need to have dark red plastic glued in: I cut mine from a plastic square photography filter I picked up cheap on eBay. Then those three pieces need gluing together at the front corners to make the shield. If you want to add some rigidity then there’s also a bottom component you can stick below the three sides. The shield is then easily removed for when you want to focus the LASER or for removing cut materials. You can download the 3D printing files from Thingiverse by clicking here, and in case you need to make adjustments that includes the OpenSCAD file. The shield also works well with my LASER extractor project, localising the area it extracts air from, which is one reason why the bottom plate is included in the design.

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Mounting a GoPro camera on a CNC machine

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.

A GoPro camera mounted to a CNC frame

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Adding a spindle motor switch

I tend to prefer to minimise safety risks when I’m using my CNC, and that includes making sure I don’t injure myself touching fast-rotating cutting bits. Obviously it’s unlikely that the motor will start up when I’m removing or attaching a bit, although it’s a little more possible when the G-Code file includes pauses for tool changing. But, to be completely sure nothing can go wrong, I made the 3D printed switch box below to allow me to isolate the spindle motor from its electrical supply. It prints as two parts which need to be glued together to fit the top of a 20mm extrusion, like in the photo above. The hole in the front is made to house a standard 18x11mm rocker switch. Click here to go to Thingiverse to get the STL files for your 3D printer.

3D model of the spindle switch box

Once the two parts of the box are stuck together, with the switch inserted, the positive wire from the spindle motor controller to the motor itself, which should be red, needs to be cut. The position where you do that needs to be planned so that the wires can be run to the box and the full movement of the motor along the CNC’s x-axis isn’t compromised. Personally I found the best place is near the controller board as on my CNC the red wire ran straight past the box position. You can use standard spade connectors crimped onto the ends of the wire, after stripping some insulation from the end. Below is a photo of the back of my switch box so you can see what I mean.

The back of the switch box showing wiring

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Clip for 20mm extruded section frame

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.

A 3D model of the frame clip

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Support foot for 20mm extruded section

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.

A 3D model image of the foot

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CNC bed-edge fence made with a 3D printer

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).

A 3D model for making a CNC router bed edge fence

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CNC hold-downs using a 3D printer

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.

3D printed CNC edge hold downs on the bed of the CNC machine

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.

3D printed CNC corner hold downs on the bed of the CNC machine

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