Thread Chamfer

[HughesTooling]

I'd like a way to chamfer the end of threads. If you chamfer a cylinder then add a thread what you get has an undercut, if you have this 3d printed in will not work. To get the correct chamfer you have to thread the cylinder the use a revolve cut. One way to get what I'm after might be to allow the offset and length to extend past the length of the cylinder.

Here's an example of what you get threading a chamfered cylinder and using revolve cut.

Mark

[rriosq]

What I do, is first do the thread, then suppress the thread and do the chamfer, and finally unsupress the thread checking chamfer is after the thread on history, so far it works for me.

Here are some pictures

[HughesTooling]

Just tried your suggestion and on my second go it worked, I should read the instructions more carefully. hopefully I remember how to the next time I need it.

Thanks Mark.

[rriosq]

Good to know it worked for you too =D

Ramon

[manuel.paulin]

Hi guys,

I found a slightly faster way : 

1) do your cylinder and chamfer it

2) create the thread (its ugly)

3) SLIDE the thread to put it just before the chamfer : magic !

(the chamfer will keep in memory the edge of the original cylinder)

[mroek]

@manuel.paulin

No doubt that it works, but I'm not sure why. The edge that was first chamfered isn't really there anymore after the thread feature has been dragged to the point before the chamfer feature, so the chamfer should really have failed, as the edge is now lost. Or at least a warning should have appeared.

The same holds true for the other suggested method. Why doesn't the chamfer feature break?

[manuel.paulin]

I think it works because both chamfer and thread are features, and not simple cuts with custom sketch.

That mean the feature will be applied on edges and volumes and will not change the body's "real" shape.

So when you add a thread, the cylinder is still in memory with its edges..

Anyway, the way that it's working and the tricks we have to do to have a nice result is to my point of view a bug, and should be corrected by Autodesk.

The normal way should be cylinder->chamfer->thread and it should work directly.

[mroek]

To have it work in what you describe as "the normal way", the thread feature itself would need to recognize the chamfered edge and continue the cut beyond the actual cylindrical face that you select for the thread feature. Certainly not undoable for the developers, but they need to be careful in such cases, because such automatic behaviour could also be undesirable in some cases.

Another method (and in my opinion better) would be to update the thread feature with conditions like "up to". That would allow you to select the cylindrical face for the thread first, and then select the end face for "up to". There could also be a start/offset condition to allow the thread to start at some offset distance from the end of the base cylinder.

[HughesTooling]

I made a tips thread here that describes the method where you drag the chamfer back along the timeline hard a while ago.

One thing to note, it doesn't work on threads with a filleted top like BSP, for this type of thread you will need to do a revolve cut.

Mark

[mroek]

@HughesTooling

Yep, that's the same as is described in this thread, and it works, but I'd argue that it really should not have worked. That is to say, at some point in time this method could break if the Fusion team makes changes to how all of this is calculated. The method is more a hack than anything else, and I believe it exploits a weakness within Fusion. It messes with the timeline in a way that should have caused errors if calculations was really happening in the timeline sequence.

I'd love to have some official comment on this from someone at Autodesk, @innovatenate could perhaps help here?

[HughesTooling]

@mroek This thread actually started out on the ideastation and was marked as solution provided and I see now it's also been moved from the ideastation. Like you say seems like a bodge workaround especially as it doesn't work for BSP threads. I think I'll put the idea back on the ideastation using the BSP thread as an example.

Mark

[TheCADWhisperer]

I think the reason that it works is because of the possibility of toggle between Cosmetic and Modeled threads.

My normal workflow is

create cylinder

add cosmetic thread

add chamfer,

then only if needed for 3D printing, toggle to Modeled thread.

First time I did this I expected the toggle from cosmetic to modeled thread to break the chamfer and was pleasantly surprised when it didn't.

Looks to me like it was done right (at least for the threads that I use).

[PhilProcarioJr]

@HughesTooling

The current implementation of the thread tool lacks the ability to set the distance past the end of the selection which is why this problem and hack exist. The reason the hack works is because Fusion adds the distance of the chamfer using the hack but doesn't work without the hack because the thread cut is terminated by the end of the selection surface. This has been a problem for as long as I have used Fusion and I have brought it up multiple times with the dev team to get it fixed.....

[HughesTooling]

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@PhilProcarioJr wrote:

@HughesTooling

The current implementation of the thread tool lacks the ability to set the distance past the end of the selection 

---

That's exactly what I asked for in the first post in the thread, when I made this thread it was a request on the ideastation. The workaround was accepted as a solution, not be me, and the thread moved to this forum.

Mark

[PhilProcarioJr]

@HughesTooling

I know....I use work arounds all the time and they are fine but as was mentioned here in the thread if they change the way Fusion calculates threads there are going to be a lot of broken files out there and a lot of headaches. So in my opinion this really needs to be fixed instead of using a hack to just get by. I will talk to Jeff again when he gets back and see if we can push something along or at least get some info on why this is not getting fixed.

[mroek]

@PhilProcarioJr

Exactly! Workarounds are OK, but ugly hacks that really shouldn't have worked (like this one) is not OK. Adding conditions to the thread tool would fix this the proper way.

[contentcreators]

A chamfer option with size/angle controls in the Threads dialog box would be useful. I hope it has been added on IdeaStation.

Regards,

Jerry

[MACABItech]

I agree that the work around is barely sufficient . The problem I am dealing with is when modelling a J1926-6 thread, I created a revolve of a sketch that included the double chamfer. In this case, I do not have the opportunity to move the thread in the timeline ahead of the chamfer because the chamfer is included in the revolve of a sketch. If I could extend the thread, I'd be okay. Right now, I'm just trying to find another ghetto solution.

[MACABItech]

I've figured I can do a revolved subtract of the cross section of the negative of the double chamfer. Ghetto.