Automatically Changing Hole Depths

[Anonymous]

This feature of Inventor - to automatically change thread depths - is stupid, and moronic, and dangerous.

I have some parts with threaded holes - the holes have 1.2" of thread (because they require 1.2" of thread).   Among other things, it was decided to change the tap drill from thru to blind - so I made the revisions and released the parts for manufacture.

*However* Inventor automatically changed the thread depth to .945 - which isn't enough thread.   The fasteners torqued up ok, but they did not generate the required clamping force.  We ended up with fine jets of 4500 psi hydraulic fluid.  (Look up 'injection injury' and click images, you'll see why this is undesirable...)

This feature of Inventor - to automatically change thread depths - is stupid, and moronic, and dangerous.

Is it still there in 2016?

[Mark.Lancaster]

Not sure what you did but my threaded depth always stays....  If my blind distance is less than the threaded length Im going to get a warning..

Its easy to blame a piece of software (and have heard this many times) but did anybody review/approve the actualy change on the drawing?  If it was critical especially if it could lead to injuries I would've made sure the information that was sent to the shop was correct.

[JDMather]

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@Anonymous wrote:

*However* Inventor automatically changed ...
This feature of Inventor - to automatically change thread depths - is stupid, and moronic, and dangerous.

Is it still there in 2016?

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What version of Inventor (including Service Pack and Update)?

Can you attach a file here that exhibits this behavior?

BTW, I would never allow this as an excuse by my students - and the only pay they are getting is a grade.  Their grade would automatically be docked by some points (probably about 10% depending on how many did catch the error).

I see that you have been having trouble design checking your holes for 3 yrs?

http://forums.autodesk.com/t5/inventor-general-discussion/wrong-value-displayed-in-drawing/td-p/3732150

[mcgyvr]

<--Grabs popcorn for the show 

[Anonymous]

2015 SP2 Update 3

Put a hole in a part 1/4-20 UNC x .520 deep.

Change it to 1/4-28 UNF and see what happens to the thread depth.  I see the thread depth change to .500 deep.

[Mark.Lancaster]

Yeah because you change the thread parameters of the hole so Inventor goes out and reads the thread table (spreadsheet) again.   Its like you are putting the threaded hole down for the first time.

Edit:  Think about this..  What happens if you put in a larger hole that requires more threaded depth, it has to change...

[Anonymous]

Start with a thru hole 1/4-20 UNC.  (see thru.jpg)

Change ithe depth from thru to distance and click ok.  (see blind_520.jpg)

Now go back and see what you ended up with (see blind_500.jpg)

[WHolzwarth]

Hmm. I could think of a message about accepting the change done in thread depth.

Perhaps one more topic in IdeaStation ..

Walter

[Mark.Lancaster]

Yes its the same thing..  Common rule of thumb is to allow 3 (or 5) thread pitches extra for the 'tap drill' over the thread depth.

So when you change the tap drill depth, Inventor is adjusting the thread length based on that tap depth.   So if you still wanted .520 depth you would need .770 tap drill depth.   Granted you can override these settings but when you're making those changes, Inventor is updating it unles you go back in and retype the value in those fields.  Once you do that, then Inventor maintains it.

Edit:  Saw WH's posting after I posted..  But yes a message might help here.  But in the end I would suggest having a proper approval process in releasing drawings to the manufacturing floor.  Because anyone can become numb to messages and you would still have the issue.

[Anonymous]

"Once you do that, then Inventor maintains it."   No it doesn't.  These parts have been made for many years, the thread depth was not selected arbitrarily, nor according to some rule of thumb.

In the past, if I changed from fine thread to course, or from thru to blind, the thread depth did not change.

This behavior is new in 2015.

[Anonymous]

"I see that you have been having trouble design checking your holes for 3 yrs? "

You know... it *might* be that the errors were caught before the parts were built.  And it *might* be that claiming the parts were built erroneously was done in hopes of illustrating why certain behaviors in Inventor should be corrected.

In either event, one thing I still have trouble with is the lack of objectivity here.

[AndyWallace]

Replying to an old thread may not be the best idea but I hope this helps someone. I just noticed this same behavior and was surprised.

Inventor 2016, Windows 7, all updates and SPs.

Created 0-80 hole with .200 depth and .150 thread. Changed hole to 4-40 and the hole depth dialog changes to .150. Clicking on the hole depth dialog then shows .2 depth again, but clicking OK causes it to revert to .150. Workaround is to edit feature and enter .200 in the dialog.

Please note that I am simply clicking in the thread depth then hole depth dialogs, not entering values, when the hole depth magically changes from .150 to .200. I then click OK because I "see" it going back to my original value and I think it is correct now.

Preferable behavior would be to have thread and hole depth dialog boxes keep their entered values when changing thread type, even if they violate what threads.xls may suggest. And honestly, Inventor should never change hole DEPTH on us automatically. That relates to design intent!

I'll upload the file so people can try it, and I've also uploaded a screencast showing this behavior which should be linked below.

Andy

[johnsonshiue]

Hi Andy,

The behavioral change in 2016 was also request by users complaining that the thread depth is not based on the table leading to errors. The better behavior here is to allow users to control if the depth can be overridden. We are aware of the request and we are enhancing hole workflow. I will work with project team to see if we can have a better solution.

Many thanks!

[kelly.young]

Hello @AndyWallace this seems to have been fixed moving forward, attached is the screencast of the 2018 release.

When changing the thread size it does update the lengths, but I think that was addressed in previous posts.

Please select the Accept as Solution button if a post solves your issue or answers your question.

[AndyWallace]

Kelly, thank you for posting that screencast. I now see that the "clicking in dialog box shows original value but does not save it" behavior has been fixed. However, that's only part of the issue. Let me emphasize:

If I specify a hole depth for design intent - like planning on a certain length fastener - why should Inventor change the hole and thread depth on me when I change thread size? This may break my design!

Yes, a good engineer should check his or her work, but why should the tool make it more likely we will fail?

In your video, I see that in 2018 it has selected for you the depths of:

#4: .349 hole depth, .224 thread

#0: .183 hole depth, .120 thread

I see that thread.xls has thread depth entries. Where is Inventor getting these hole depths? It appears they are about 3X the major diameter in the table. So Inventor is trying to be helpful as if I am creating a new blind hole and giving me recommended minimum drill and tap depths.

What I would prefer is that for an existing hole, please keep what I've entered in the dialog when switching hole threads. To me, this is much safer than swapping in the recommendations. I'd even prefer blanking out the dialog and being forced to enter numbers again.

Andy

[SBix26]

Generally, I take the default depths, and I like that it changes those according to the thread size.  

Perhaps a more nuanced approach would be for the software to recognize default depths vs entered depths and adjust defaults, but not adjust entered ones.

Sam B

Inventor Professional 2018.1.2
Vault Workgroup 2018.0
Windows 7 Enterprise 64-bit, SP1

[AndyWallace]

Sam, that's exactly what I would like. If I had changed something for a reason, leave it changed when switching threads. Andy

[kelly.young]

@AndyWallace just wanted to show you that it doesn't automatically change the dimension like it did before, I could see how that would be a bit misleading.

As for the existing hole change, that is something that could be addressed. If you would like to create an Inventor Idea, add this post link to it, and share the idea back here I'll give you a vote. Best way to get the ball rolling.

Edit: Check this idea and see if it is similar or something you can add to.

Please select the Accept as Solution button if a post solves your issue or answers your question.

[coop_brian]

I never noticed this issue with 2015, but since updating to 2018 (2018.2, build 227), any time I change anything with the threads in the hole dialog I get unpredictable changes in the counterbore/countersink diameter, hole depth, and thread depth fields. Unpredictable in that sometimes nothing changes, sometimes it changes to some detault vault, and sometimes it will change back to a value I had previously typed in (this only seems to happen in the cbore/csink field). This is especially frustrating when I have depths set via parameters (so that the hole depth will automatically adjust to break thru one wall, but not hit another feature beyond that) and it deletes that value and goes back to the default from thread.xls.

Having software make these assumptions is terrible in practice (except maybe when you initially create a feature) - even if you change the thread size or pitch. We use threads to adjust the position of items nearly as often as we use threads for fastening and I'll adjust thread pitch coarser to reduce the number of turns to get the required adjustment range, or finer to get better positional accuracy. Sometimes I need the hole's ID to stay close to the same so I'll adjust the thread size and pitch simultaneously and the last thing I want to have to do is correct the depths multiple times (especially when I have them set to some other parameter as I mentioned above).

I'll attempt to grab a screencast when I'm working on my next part...

I did also post a comment to the Inventor Idea, but since that's been around since April of 2015, I'm not holding my breath for these changes to be implemented.

[dougnano]

I have been having this problem too, since sometime around 2015 or perhaps even earlier.  Using Inventor 2019 now and this "feature" (which seems more like a bug to me) has been around in every release since whatever release it was that they made the major change to the appearance and layout of the hole feature dialog box,  from the original dialog box that had been around since the very first Inventor release around the year 2000.

Every time I change a threaded hole depth, the thread depth gets reset to the default thread depth, whether or not the hole depth was shallower than the thread depth that I had input previously.  This also happens with counterbores.  And often, when I enter any hole depth parameter, it will reset to the default all by itself a split second after I hit "enter" on the new depth. It's been extremely frustrating for years, I can't believe more people haven't complained about this.