How to mill internal threading?

Hello, I want to mill something like https://www.kickstarter.com/projects/1847552530/imbue-the-magnetic-tea-infusing-vessel?ref=discovery

The lid is not hard to model, but I am not quite sure what type of tool to use to create the threading. I’ll be modeling everything in Fusion 360.

Has anyone done anything like this?

I am no expert and just getting to know the cnc, but I think you could probably do it with a single profile thread mill.

1 Like

The thread mill is the best solution. That said, many of the G codes used for thread milling are not supported by GRBL. It is possible to rewrite the g code to handle the thread mill operations within GRBL.

See there:


mark

The threading on that lid is very coarse (to fit the jar) and looks to be pretty forgiving. The suggested single profile threadmill may work, although they max out at a depth of cut which may not be deep enough for the threads on your jar, plus they cut a sharp V so would be many many passes to get any sort of round profile.

I think in a perfect world you would want some sort of cutter with a rounded profile, sort of like this:
http://www.grizzly.com/products/Convex-Milling-Cutter-1-8-Radius/H3341

Of course you need the diameter to be small enough so you can make a helical thread, rather than just a concave groove in one plane. Still would need to make multiple passes but may get you closer.

OR, you could 3D print it :wink: