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.