A person putting a screw into a CNC spoil board on the left of the image. Their drill is chartreuse and black. Clamps hold a rectangular board down at all four corners. The spindle of the CNC is just visible on the right hand side of the image.

Workholding Options For The Beginner CNC Operator

July 23, 2024 by Navarre Bartz 6 Comments

Designing a file to cut on a CNC is only part of the process. You also have to keep it in place while the machine does its work. [Garrett Fromme] walks us through five different work holding techniques.

Since every project is different and stock material can vary from thin veneer to much larger pieces, there’s no one right work holding method for every project, and not all methods are applicable to all materials. A vise is great for small projects that need to be held very securely and won’t be damaged, vacuum tables can make switching pieces quick in a production environment, fasteners will hold a piece securely at the expense of your spoil board, clamps are fairly versatile but fiddly to setup, and tape and CA glue are quick but require more consumables.

[Fromme] does a quick demonstration of setups with these different methods and their limitations, which is a great place to start for the beginner CNC operator. Just like 3D printers, CNCs are a far cry from the replicators in Star Trek that can automagically create what you ask it to, but proper workholding lets you waste less material and operate the machine more safely.

Our own [Elliot Williams] had a look at how CNCs aren’t as automated as you think. If you do need some CNC clamps, you might try these printable parametric clamps, or if you want something more beautiful, give these metal toe clamps a go.

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OpenSCAD Cranks Out Parametric CNC Clamps

June 11, 2024 by Tom Nardi 7 Comments

If you’ve ever used a CNC router or mill, you’ll know how many little things need to go right before you get anything resembling acceptable results. We could (and probably should?) run a whole series of posts on selecting the correct bit for the job at hand and figuring out the appropriate feeds and speeds. But before you even get to that point, there’s something even more critical you need to do: hold the workpiece down so it doesn’t blast off into orbit when the tool touches it.

Now that might sound like an easy enough job, and for basic flat stock, it often is. But if you’ve got an oddly shaped piece of material, you’ll quickly realize how inadequate those trusty c-clamps really are. When you get to that point, it might time to check out these OpenSCAD hold down clamps from [ostat]. Thanks to its parametric nature, you can plug whatever dimensions you need into the script, and in a few seconds it will spit out an STL file for a bespoke clamp that you can print out and put to work.

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A Different Kind Of CNC Workpiece Clamp

March 15, 2014 by James Hobson 16 Comments

[Mike Douglas] joined the world DIY CNC machining recently with a FireBall X90 CNC router. Instead of buying an expensive aluminum T-slot bed, he decided to try something we haven’t seen before…

His local hardware store sells aluminum bar clamps designed for clamping wood together — the best part? Only $10 each. What he’s done is added the bar clamps along the two sides of his bed, by adding plywood braces attached to the outside frame of the machine. He is losing a few inches of his usable bed area, but the added convenience of a quick clamping system is well worth it.

With the clamps in place, all he has to do is add two wooden braces (the black bars in the image above) to hold his work piece in place. This wouldn’t work very well for cutting metal, but this CNC router isn’t designed for that anyway.

Too bad he didn’t finish it sooner — it would have been a great entry for our recent Hackaday Hackerspace Henchmen CNC contest!