3D Printed Magnetic Hold-Down

3D Printed hold-down magnet developed for Glowforge.
Hold down provides five clamping heights on five corresponding edges marked (cryptically) 0 thru 4.
Bottom loaded magnets provide maximum attraction to metal tray

Uses Round 1.26"D x 0.06" (32x1.5) magnets (stack of 3 or 4 each).
NOTE: Magnets are press fit and require a vise with soft inserts for insertion.

Mag,HoldDwn,5pt,LG.STL (7.3 MB)


Clever design. Sharing as first post. Thanks so much and welcome. Is useful for the various thicknesses of common materials.


Interesting design idea. but wondering about the magnetic field above the magnets? :thinking: It should have been obvious to us before but only realized recently that a high-speed spinning fan is not happy in the presence of a strong magnetic field. :crazy_face: Good shielding can greatly reduce the size of that field, but I have changed my practice of using magnets by default to only when necessary and applying a steel flashing material to the top even then.:sunglasses:


Looks great! Thank you!

Yeah. I’ve been using a set of roughly nickel sized neodymium magnets to hold stuff flat on the crumb tray. With a recent update to the GF firmware, they’ve apparently enabled (or maybe just tightened the limits) fan speed detection. Now, even though I’d done dozens of jobs with magnets without any apparent issue, I can no longer use magnets. If the air assist fan gets near a magnet the GF will abort the print job because the motor speed has been slowed down by the magnet’s stray field.

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Once I realized what was happening and thought about the electrons going every which way that they shouldn’t I did not want that happening even if it did not abort the design.

No worries, all the electrons still go where they’re supposed to go, the magnet doesn’t stop that. It’s a purely magnetic effect. The motor has magnets, the hold downs are magnets, the fields interact and the motor doesn’t run at the same speed when they do.

The question is how much speed variance the assist fan can tolerate and still work effectively, especially given the variance isn’t going to last very long. Detecting if the fan is busted and not running at speed at all, ever, is definitely a good thing. But a slight change in RPM as it passes over a magnet may not be as dire. I don’t know one way or the other. I’d guess GF does, which is why they made the change to fan speed detection. But it didn’t seem to be hurting me any before… and now, using magnets is problematic.

I hate to say it, but I used the same magnets, they will stop the air assist fan and cause an error if the fan crosses the path.

I wonder if printing these holders with one of the new metallic composite filaments could provide some (albeit minimal) shielding? Brass?
Apologies, that’s not an experiment i have time or money to complete.