CNC machining is only as good as your hold-down. If you can’t secure your workpiece, forget about accuracy.
For industrial CNCs, that means investing in vacuum systems, which work great for panels and bigger parts, but as the part gets smaller, hold-down gets trickier. CNC routers smaller than 4x8 might not even have vacuum hold-down.

Computer files are available to machine clamping and alignment tools right on your CNC. You find some plans free on forums and for sale in places like Etsy. And, of course, a number of companies are offer clamping and alignment tools. One of the more recent is a CNC work-holding kit by Microjig.

What’s in the kit?
This kit offers four different work-holding solutions designed for CNCs with no vacuum table. They are all designed to anchor in the MicroJig  MatchFit system, which is a do-it-yourself panel with dovetail slots. The kit includes instructions on how to build a spoilboard with dovetail slots to fit all the tools.

Those tools come in four flavors. First are three edge guides for repeatable alignment of rectilinear parts. Second are two ring clamps using offset circular action to apply side pressure. Third are two ramp clamps with a notched pressure edge to apply side pressure. And fourth are four U-pads to secure parts from 1/32-inch to 1-1/8 inches thick with downward pressure.

How do they work?
You can convert an existing spoilboard to a dovetail slot board for maximum versatility. But you also can use many of the tools in existing T-slots or screwed down directly to your existing spoilboard.

I screwed down the edge guides to my existing spoilboard for a huge improvement in repeatable alignment. I found the ring clamps were much more secure than some DIY cam clamps I made from downloaded files. The ramp clamps work well on irregular and straight parts. And the U-pads are a clever solution to hold down thick and thin workpieces.

All these tools are made out of rugged plastic that won’t damage your tooling if you accidently send the router into a clamp.
The whole kit runs about $120 online, which is probably less than the cost of your time and materials to try to machine similar clamping devices yourself. Check it out at microjig.com.