CNC Hold Down Clamp Set

thingiverse

This is a set of CNC hold down fixturing parts for use with a 2D CNC fixturing table that has 1/4 20 threaded inserts, 2.3" on center apart in a grid layout. Why 2.3"? Because it was a happy medium between the 3" on center layout I have used before where the holes were too far apart, and a 2" on center layout where I would have had to buy MANY more threaded inserts. The clips and clamps will work on any spacing, but the side rails won't. The system is designed so that you can put down a corner panel and/or one or more side panels, flush your work piece up to it/them, then use the clips on top of the rail with a 1/4 20 screw (I prefer button head, hex drive bolts) going through the clip, through the rail, into the fixture table. The clamp pieces can then be used on the sides where you don't have a rail or corner installed. They have minimal overhang on to the work surface to minimize the chances of hitting them when you cut your projects. Multiple heights of clips and clamps are provided to cover materials from 1/2" to 1" thick, including when you put a 1/8 or 1/4 spoilboard underneath your project, on top of the fixture table. The clips that go on the rail have the measurement on the clip for the total height of both rail and clip. The clamps have the measurement of the total height on the clamp. Remember that for the greatest strength, print these as if they look like they are on the side. It takes longer, but it means that the print is stronger relative to the direction of force that will be exerted by the CNC machine. When printing, include supports, particularly for the hole where the bolt goes. I've printed these in ABS, using a brim to make sure they stay down, with 100% infill. You could probably get by with less, but I don't want to have to print these a second time.