Missing thread standards

[DRoam]

Is anyone else impaired by the lack of some of the common thread standards?

In particular, at this time I'm in need of the NPSM (National Pipe Straight Mechanical) and SAE standards (also known as O-Ring Boss; it's more of a hole type than just a thread type).

Those are just the missing standards I find myself needing; there are other thread standards which are not included in Inventor.

I am wondering if I'm alone in this or if others are affected as well?

I'm also wondering if anyone knows of a workaround, such as a way to add thread standards manually? I'm thinking iFeatures might be a possible solution for SAE holes, but I only have a basic knowledge of what iFeatures are; I've never used them myself.

[pball]

I made up this SAE ifeature back when I had to do some tube and pipe for hydraulics. It's modeled accurately according to the documents I found at the time. It's not as good as a built in feature since you can't use the hole dimensioning feature but at least no more drawing them.

I know you can add different sizes of holes to existing hole types but I'm not sure if you can add a whole new type of hole to the Inventor thread.xls file. You can make an Idea Station post about adding more styles of threaded holes to try and get Autodesk to add more.

[JonathanMLanderos]

Forgive me for speaking off the cuff.  I'm not intimately knowledgeable with SAE ports, just what Google showed me in a couple of minutes!

 But depending on what you need, you *might* be able to modify the thread.xls file to reflect the port, depending on what you need.  You'd have to choose the threaded hole, and make sure to counterbore it, but you (at least in theory), could set them up to have the correct dimensions. 

You can always add tabs to the thread.xls file. 

It's probably a "six of one, half dozen of the other" approach.  But I thought the suggestion might spur an idea or two. 

[JonathanMLanderos]

Oh!  It just dawned on me as I posted. 

There are SAE port ifeatures on CBliss.com  They're older, but they might just save you a lot of headache! 

http://www.cbliss.com/inventor/iFeatures/

[karthur1]

For the SAE ports, I too have made an iFeature for these.  The depths in my ifeature can be adjusted.

There probably is a way to add a custom thread if you have the time to mess with the Thread.xls file.  You can find the Thread.xls finle location by going to the Tools > App Options, File tab.  The location is listed under the "Design Data".

Kirk

[Curtis_W]

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karthur1 wrote:

There probably is a way to add a custom thread if you have the time to mess with the Thread.xls file...

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Hi DRoam,

If you are interested in modifyng the Thread.xls file per kauthur1's suggestion, here are some links that might be of interest:

https://knowledge.autodesk.com/support/inventor-products/learn-explore/caas/CloudHelp/cloudhelp/2014...

https://knowledge.autodesk.com/support/inventor-products/learn-explore/caas/CloudHelp/cloudhelp/2014...

I hope this helps.
Best of luck to you in all of your Inventor pursuits,
Curtis
http://inventortrenches.blogspot.com

[karthur1]

Ok.... so I was bored.  Attached is a spread sheet with the NPSM threads up to 2in.

You will have to edit your thread.xls and paste this into it. If you have Inventor open, you will have to restart it before it will show up when you place a hole.

If you have troubles, post back.

Kirk

[DRoam]

You are all awesome, thank you!

I'm looking into the options you've all presented, will post back with my final verdict. Thanks again!

[Anonymous]

Thanks for the worksheet.

I know this was posted a while back, but I ran into an issue.

I added your worksheet to my Thread.xls workbook.

However, when I place a 2 NPSM thread on a Pipe with an OD of 2.375 (for Size 2 Pipe), I get the error: Inappropriate thread size.

I am running Inventor 2017 Build 199. Release R2 - Date Mon 07/18/2016

Any suggestions?

Thank you.

[karthur1]

Chuck,

Per the Mach Handbook (and the NPSM spreadsheet), the max size for a 2in NPSM thread is 2.351in.  Try using that values for the OD and see if that works.

Kirk

[Anonymous]

karthru1,

Thanks for the reply. 

Yes making the OD of the pipe 2.351 does work.

However, when I place standard pipe size 2 from my content center, the OD is 2.375 ~ 2.80. 

I am able to apply a NPT (tapered) thread to that diameter just fine. As a matter of fact, all of the other threads work fine except the NPSM I added. 

There must be some super secret that Autodesk is not sharing. Else, they know it will not work and therefore did not include NPSM in the Thread.xls workbook as a result.

I am at a loss. It just will not work.

[Anonymous]

karthur1,

The only way I was able to get it to work without getting an "inappropriate thread size" error was to look at it backwards from what you suggested.

I changed the External Thread Major Dia Max value to be what the STD Pipe OD is for any given size.

i.e. Pipe Size 2 has an OD of 2.375"

      The Major Dia Max for that thread is now 2.375"

I really, really don't like having to do that and I am not sure how that will affect anything else, as in DWGs, etc.

What do you think it affect, if anything?

Thanks

[karthur1]

Chuck,

The values in the table are from the Machinery's handbook so they are correct for that thread. Anytime you put a NPSM thread on the OD of a standard size pipe, the pipe will have to be turned down... or it will be too large for the thread.

The pipe size for a 1 pipe, for instance is 1.32in.  Major OD of NPSM external thread is  1.293.

The pipe size for a 1 1/2 pipe, for instance is 1.90in.  Major OD of NPSM external thread is  1.877.

These are just two examples of comparing values in the table and the common pipe sizes.

Kirk

[DRoam]

@karthur1 is correct.

I think the most technically proper way to do this would be to, before applying the NPSM thread feature, use a cut extrusion or some other method to cut down the OD of the pipe where the threads will go. This mimics the "turning down" which, as Kirk described, is necessary in real life, and simultaneously gives the threaded section the proper OD that Inventor is looking for.

The problem with this is you need to know what that proper OD is, so you'll need to reference a table such as that in the Machinery's handbook, or this one here. Or just just reference the thread.xls file that contains your NPSM data.

Technically you could modify the major diameter data in the thread.xls file to accommodate a larger OD, and it won't affect how that thread is called out on a drawing because those values are just for modeling purposes. But I wouldn't recommend it.