Cutting a shallow slot/groove in aluminum

Hello, I’m pretty new to CNC and have been slowly working up from acrylic to cutting aluminum on my Nomad 3. I’ve only been using the #102 1/8" square end mill, but I have some geometry I want to mill that would require some thin undercuts. Imagine like a camera cold shoe:

cold shoe

From looking around, it seems like I’m mostly finding T-slot cutters for waste boards that are too thick. These slots are only about 2mm deep.

This is probably about the closest I’ve found but the depth is about 3mm, so still thicker than I would prefer. I’m also not certain about its use on aluminum. Any help or guidance would be greatly appreciated!


Harvey Tools has tooling for this sort of thing in a variety of sizes:

(sit down before checking the prices though)


Amazing! Thank you so much. I think this is just what I was looking for. Prices don’t seem too bad, but maybe my tune will change after I destroy a couple…

And another newbie question: I’d want to stick to the uncoated carbide for cutting aluminum, correct? I’m using ZrN end mills now, I’ve heard AlTiN is bad for cutting aluminum because it sticks and welds.

There’s a separate category of tools for non-ferrous metals.

where they offer plain carbide or a coating (tib2) suited for non-ferrous metals.


Those seem like pretty fair prices given the costs from people like CMT, these are speciality tools.

Be aware that on the Nomad you’ll have to go pretty slowly with a tool like this to avoid chatter and vibration as it’s a really uneven cutting load at quite a distance from the spindle center. Also you’ll want a tool which is less deep than the slot so you can move up and down as you move across into the slot to give clearance so the cutter doesn’t bind in the slot (like a saw binding up in a deep cut).


Thanks for the tips. I’ll be sure that I’m set up for that type of clearing when doing the CAM, that makes a lot of sense. Appreciate it!

Also, checking out those TiB2 coated tools, thanks Will!

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If you turn the shape on its side it’s no longer an undercut.