Anyone tried Thread Milling aluminum with a dovetail bit?

I’m still on the fence when it comes to working with aluminum. So, before working with it, my OCD-tendencies led me to an ocean of info. While swimming in the sea and after a few “dead (link) end” fishing expeditions, I finally stumbled upon this post:

in the Thread Milling (in Metal) on the Shapeoko (3) - #46 by RichCournoyer thread
I’ve been looking for this exact thing since I found a cross-sled vise at a garage sale two years ago!
Now, I don’t have a solid block of aluminum, but I do have a strip of 1/4" thick, 1" wide flat bar and same thickness angle too.

Before ruining one of my taps, I remembered I have 2x CMT/Orange Tools dovetail bits (one has 1/2" shank):

Thought I’d ask peoples opinion as to whether or not this bits’ angle is suitable for threading.


I don’t think that would work.

My inclination would be to buy an inexpensive tap to use, then chase the threads w/ a better one, or try modifying the tap as Rich did.

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You can make an impression of a thread-like feature and make it engage, but it would be so shallow. You might as well just use the thing you are putting into the thread to cold form the thread into the aluminum.

It’s like saying hey, I got two table saw blades, can I use them together like a gear set? Not really the same.

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A dovetail bit can’t be used as a thread mill, the cutting edge is a right-angle triangle so it can only possibly cut half the thread. To thread mill, there needs to be a triangle with the base parallel to the shank and an angle of 60° at the tip:


There are also thread mills like these, with multiple cutters:



Lucas is right with this. Considering thread-mills can be had for $20-$30, it’s worth it to get the right tool for the job.


Thanks for the quick responses everyone.
Was skeptical but not 100% sure.
Well, back to the grindstone and the “Can’t wait to get done working so I can go try…”, that will have me chomping at the bit until I finish the harvest.
Thanks again y’all!

If you had a Shapeoko big enough to cover your farm, the Shapeoko could harvest for you :wink:

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