Problem found with Threading Tool and Hole Tool Chamfering Threads in free version

[jle2199]

I have been having a problem with the Hole Function in Solid.

When I ask 360 to make a threaded hole with a chamfer on it, the chamfer does not leave a leading thread for the threads to begin.

The instructor struggles with it in the attached video, and does not realize that the problem he has, the "chamfer colliding with the threads" is actually proper, and not what he changes it to, as what he changes it to does not allow for a male thread to mate. 

This also happens with male threads and you get a... Excuse me I lack a better description,  "glans" on the ends of your male threaded parts.

https://youtu.be/AfeCRrYsAys?t=400

[HughesTooling]

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@Phil.E wrote:

Thanks for the additional details. Would it make sense for the thread command to include a chamfer setting for rods and holes?

Have you noticed that a rod can be chamfered after the thread. Is this an appropriate outcome?

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That would make sense, also needs to work with the hole tool. The hole tool does have the option to chamfer thread holes now but it adds the chamfer before the thread so leaves an undercut rather than running out through the chamfer.

You can add a chamfer like you show but it will not work on BSP threads. The workaround adding a chamfer to a cosmetic thread then changing the thread to modeled only works because part of the original cylindrical surface remains after the thread's created. Whitworth threads doesn't leave the cylindrical surface behind so you have to use a revolve cut.

This shows the difference. If you only thread part of the rod, you can see selecting below the thread the original surface is part of the thread but not for BSP threads.

[TheCADWhisperer]

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@Phil.E wrote:

1. Would it make sense for the thread command to include a chamfer setting for rods and holes?

2. Have you noticed that a rod can be chamfered after the thread. Is this an appropriate outcome?

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@Phil.E 

1.  Out on the shop floor virtually every male or female thread is created with a chamfer (lead-in).

If this is not done the helix ends in a very weak, sharp sliver of material that is easily damaged causing difficulty in thread engagement (and incorrect torque reading where that is important).

2. Using this method several selections must be made to complete the Chamfer feature and the results are not robust. Also, these are spline edges - not circular edges which is the real world machining geometry.

There is also the issue that the Chamfer tool might try to select the helical edge rather than the spline (not circular edges).

This entire issue is a long standing issue that I and others have pointed out hundreds if not thousands of times over the years.  Interesting that it is finally getting attention.

[HughesTooling]

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@TheCADWhisperer wrote: 2. Using this method several selections must be made to complete the Chamfer feature and the results are not robust. Also, these are spline edges - not circular edges which is the real world machining geometry.

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All you need to do is highlight what's left of the core diameter and find the edge at the end face and it's reasonably easy to select. All you need is this edge.

[Phil.E]

I come from a manufacturing background and fully understand what a lead-in chamfer is. I was only asking if the thread command should include it. What do you think about that question?

[seth.madore]

Wouldn't that be part and parcel for the Countersink option in the Hole Command, or are you also referring to the bottom of the thread (assuming it's a "thru" hole)? 

[Phil.E]

I'm talking about the thread command, not the hole command. If it's common to thread an existing cylinder shape, whether a hole or shaft, and also include a chamfer in any way relevant to the thread being applied, should the Thread command include a chamfer setting.

[jle2199]

@seth.madore You bring up another good point, possibly unintentionally...

Is it possible to have an option to chamfer both ends of threaded thru holes?

[seth.madore]

Hmm, good question.

A possible modeling flow would be (in the case of a shaft):

1. Sketch diameters
2. Extrude
3. Chamfer end of shaft
4. Apply threads

If one were to follow step 3, wouldn't the resulting thread still have an issue?

It seems like we need to handle both methods:

Chamfer already there? Let's scoot the threads fully out and fade away

No chamfer there? Let's give users an option to apply one where the thread doesn't stop short

 

[jle2199]

@seth.madore  
I mean, in real life you make your hole/rod, chamfer it, and then thread it, and then clean up the threads after if you need to, unless you're single point threading, then you can chamfer it after because it doesn't matter as much to get a tap or die started, so I would imagine you'd want the program to 

1. model hole/ rod

2. model chamfer

3. model thread as if chamfer not there 
like you suggest 🙂

I suspect this can differ for single point threading, but that's another subject.

[seth.madore]

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@jle2199 wrote:

I suspect this can differ for single point threading, but that's another subject.

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Indeed. I'm interested in helping to guide the workflow for 3D printing and the proper use of the Hole and Thread tools in this application. Machining has zero use for modeled threads (aside from the thread data itself, which may see some use at a later date 🤐)

[jle2199]

I was under the impression that people were exporting files from Fusion 360 to CNC machines/ CAM programs, which as you know operate like slicers but do understand the need to focus on one thig at a time.

[seth.madore]

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@jle2199 wrote:
I was under the impression that people were exporting files from Fusion 360 to CNC machines/ CAM programs, which as you know operate like slicers but do understand the need to focus on one thig at a time.

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This is not correct, CNC machines and Fusion CAM do not operate like slicers, only 3D Printing software operates as such.

That said, I'd like to keep this discussion focused on simply thread/hole chamfer creation and avoid veering off into tangential discussions.

[jle2199]

I meant that they operate like slicers in the "it makes the NC / G-Code file" fashion.

However, yes, the threading tool is the topic, we should focus there.

[jle2199]

@seth.madore
BTW, I'm 40, and I was introduced to AutoCAD when I was 13 taking an after school course at Shawsheen Tech in Billerica, I have been using it in some form or another (except the period I was using DraftSight, which was literally old AutoCAD...) for 26 years.

I have always always always appreciated the features and innovation that AutoCAD has included.