topic Re: Tri Form Thread Milling in Fusion Manufacture Forum

Tri Form Thread Milling

dlewis1000 — Thu, 16 Apr 2026 17:27:36 GMT

Is it possible in fusion to generate a proper toolpath for a tri form threadmill? Currently I have 3 teeth on my threadmill but the tool wants to spiral all the way from bottom to top of hole. The proper way to run a multi pitch like this is to mill one pitch, step up 3x pitch, mill another pitch, etc. No one should be running one of these threadmills all the way up or down a thread. Puts all the wear on the top or bottom tooth and is not acceptable.

Red boxes in the picture are portions of the toolpath that shouldn't be there.

Re: Tri Form Thread Milling

lauri_barnhart — Mon, 20 Apr 2026 14:54:40 GMT

@dlewis1000 - Welcome! Thanks for your question.

I wanted to follow up to see if you're still facing this problem?

If you were able to fix the issue, please share what worked for you.

If the issue persists, let us know with an update so we can assist further.

Thanks!

Lauri | Community Manager

Re: Tri Form Thread Milling

dlewis1000 — Tue, 21 Apr 2026 18:05:04 GMT

Yes I am. Never got a reply on here.

Re: Tri Form Thread Milling

seth.madore — Tue, 21 Apr 2026 18:59:31 GMT

No, this is not possible in Fusion. Well, technically it's possible, but involves a workaround so horrible I don't even want to recommend it.

Effectively, you need to set your height for a certain amount of revolutions, duplicate your toolpath, modify your heights, duplicate again. Like I said, it's terrible. There's an old ticket for this, but I think you're maybe the 2nd or 3rd person to request this in several years.

Don't get me wrong, I'd love to have this in the product, but the amount of requests suggest that it's a niche issue.

Re: Tri Form Thread Milling

dlewis1000 — Tue, 21 Apr 2026 19:16:49 GMT

Yeah you're right that is terrible but that's what I'm going to have to do. It's just not ever acceptable to run a multi pitch this way.

Considering how few people I've met across the country and back in over 100 shops that even know that's how you're supposed to run one of these thread mills, I'm not shocked there hasn't been more requests. This should be treated as a much larger issue than it looks to autodesk just from requests.

Re: Tri Form Thread Milling

seth.madore — Tue, 21 Apr 2026 19:20:53 GMT

I think it's also indicative of the amount of users who thread mill with full form threadmills or single form and just work bottom to top. The former has no need to worry about multiple axial depths, the latter expects to go the entire distance.

If you're referring more to spirit of Moldino line of 3 flute / 3 threads types of threadmills, they are 100% designed to work the same as a single form, just spinning in reverse and going top > bottom

Re: Tri Form Thread Milling

dlewis1000 — Tue, 21 Apr 2026 19:40:02 GMT

There's two other things to be considered also when it comes to the requests. How many people out there refuse to take the time to make the request in the first place, I know that's the vast majority of people I've worked with. Also how many people get their start on Fusion and have no idea that's even an issue.

I'm talking about any type of multi pitch. I know the exact type of tool you're talking about and have ran them but think about a typical tri-form thread mill going bottom to top. Or an indexable thread mill like I'm running right now that can cut 2.0 deep but has an insert that's only 0.75 long. They are not meant to be ran that way and it just completely wipes out the potential tool life on what is typically an expensive piece of carbide.

Re: Tri Form Thread Milling

programming2C78B — Wed, 22 Apr 2026 10:42:10 GMT

Can you put the toolpath into a Linear pattern around Z instead? Safest is probably start with the lowest depth then pattern it up (so the retracts and clearance are extra high)

Re: Tri Form Thread Milling

seth.madore — Wed, 22 Apr 2026 11:34:25 GMT

:smacks-head

I don't think I've ever patterned about the Z, but that's a perfectly fine solution (in lieu of us doing something in the toolpath)

Re: Tri Form Thread Milling

dlewis1000 — Wed, 22 Apr 2026 11:35:30 GMT

Good idea. For now that will work.

Re: Tri Form Thread Milling

lauri_barnhart — Fri, 24 Apr 2026 12:43:37 GMT

Hello @dlewis1000, we appreciate you posting your question.

Did the information provided by @seth.madore or @programming2C78B help?

If yes, please mark the reply as the accepted solution.

This helps other users benefit from the information.

In case you still need help, please provide an update here so we can help you best moving forward.

Best,

Lauri | Community Manager

Re: Tri Form Thread Milling

dlewis1000 — Fri, 24 Apr 2026 13:21:54 GMT

I can't do that. These are work arounds for a larger problem, and while I'll use this info to get by it's not the solution. The only thing I'll accept as a solution is a commitment to implement the real fix into the software.

Re: Tri Form Thread Milling

seth.madore — Fri, 24 Apr 2026 14:14:01 GMT

There is a ticket open to investigate this, but it's very low on our priority list for the foreseeable future