Custom thread files

[MRWakefield]

Hello all,

Inspired by a recent post on this forum by @AlanMueller where he posted a custom thread file for UN wire thread inserts, I am posting a number of thread files that I've created or curated from various sources. Perhaps this thread (excuse the pun!) could become a repository for custom thread files people have created that they would like to share with the rest of the community.

Attached you will find a zip file which contains the following thread files:

• ANSIMetricMProfile - Non Std
• British Brass Thread
• BS 00093 British Association (BA)
• BS 811 British Standard Cycle
• BS 84 Whit Form
• ISO 2904 Metric Trapezoidal - Non Std
• ISO Metric Non-Std Sizes
• Metric Camera Filter
• NPSM Pipe Thread
• PGGlandThreads
• RMS
• Wire Thread Insert - BSF
• Wire Thread Insert - BSW
• Wire Thread Insert - ISO Metric
• Wire Thread Insert - UNC
• Wire Thread Insert - UNF

I can't vouch for the data sources for all of these files and some might have originated from right here on this forum. Some files might be incomplete or contain errors so please double-check!! If you do find anything wrong or missing please post the details here and I'll add and/or amend accordingly (unless you want to do it yourself 😉).

So if you have a custom thread file perhaps you'd like to post it here and share it with the community.

EDIT 05/03/2024:

I'll start adding any additional files to this first post to make it easier to find any you might be looking for.

EDIT 09/06/2024:

I have updated the Custom thread files.zip with a new (corrected) version of the NPSM thread file in response to @user015M86Y's post #5. Hopefully this is now correct!

[MRWakefield]

Prompted by an enquiry by @cristianoravaioli regarding an M32x1.25 thread I've added it to the ISO Metric Non-Std thread file. I've also removed the word 'Sizes' from the file name.

[MRWakefield]

I've updated the British Standard Cycle thread file with spoke, nipple and special sizes. Usual caveats apply! See attached.

[MRWakefield]

I've updated the zip file attached to my first post with a corrected BA thread file. I can't remember where I sourced the original but it had a number of issues. Hopefully this one is now correct.

[user015M86Y]

Hi, I check the NPSM Pipe Thread xml file and I found several value error

I noticed that this value error systematically appears for internal threads

I continue the check

Example :

<ThreadDesignation>1/4 NPSM</ThreadDesignation>

 <MajorDia>0.475</MajorDia>
<PitchDia>0.4945</PitchDia>
<MinorDia>0.475</MinorDia>
<TapDrill>0.453</TapDrill

<ThreadDesignation>3/8 NPSM</ThreadDesignation>

<MajorDia>0.608</MajorDia>
<PitchDia>0.62995</PitchDia>
<MinorDia>0.608</MinorDia>
<TapDrill>0.594</TapDrill>

[MRWakefield]

Thanks for reporting this. I can't remember where the data originated from but I'll check it out and repost a corrected version as soon as I can.

[MRWakefield]

I've updated the zip file in my first post with a corrected NPSM thread file. If you find any other errors just let me know.

[user015M86Y]

Hi, I find other several errors and I check the complete file

See attached the file

All errors are in comments in front of each value

Hope this help

[MRWakefield]

@user015M86Y wrote:

Hi, I find other several errors and I check the complete file

See attached the file

All errors are in comments in front of each value

Hope this help

---

I'd be interested to know the source of your data as I couldn't find anything online that quoted the minor diameter of external threads or major diameter of internal threads. I had to calculate those values myself (expanded on below).

All of the v2 data is calculated directly from the ASME B1.20.1-2013 standard document. This document (and most online resources) quote minimum and maximum values for Major Ø and Pitch Ø for external threads and Minor Ø and Pitch Ø for internal threads. The standard thread files supplied with Fusion use the mean value of the lower and upper limits of size for each of the diameters so I follow this method when preparing custom thread files. The standard document doesn't give values for the external Major Ø or internal Minor Ø so these were calculated by using the equation for the depth of the thread in each case. For external threads this is 0.64952*P and for internal threads this is 0.54126*P (where P = Pitch (1/TPI)).

So, let's take the external 1/8-27 NPSM first:

Max Major Ø = 0.397"

Min Major Ø = 0.390"

Mean Major Ø = 0.3935"

Pitch = 0.037037"

Depth of thread = 0.64952*0.037037, = 0.0241

Minor Ø = 0.3935-2*0.0241, = 0.3453"

The value in the file is = 0.3454" so is one tenth of a thou different to the result above. This difference will be down to rounding and is not significant here. Your comment says this value should be 0.3485". Can you elaborate on where this value came from or a formula for calculating it?

Now let's take the internal 1/8-27 NPSM:

Max Minor Ø = 0.364"

Min Minor Ø = 0.358"

Mean Minor Ø = 0.361"

Pitch = 0.037037"

Depth of thread = 0.54126*0.037037, = 0.020

Major Ø = 0.361+2*0.02, = 0.401

A difference of 1 tenth of a thou from the value in the file, again due to rounding. Your comment says this should be 0.3976. Again I'd be interested in where this value has been obtained. Your second comment regarding this thread says the Pitch Ø should be 0.3759, against my value of 0.376 (a difference of 0.0001"!). The Max Pitch Ø according to the standard is 0.3783 and the Min is 0.3736 (a tolerance of 0.0047") so I'd say the 0.0001" difference between my value and your value is insignificant!

I have briefly been through the other comments and any discrepancies in my opinion are similarly insignificant or questionable as to which is correct.

Bear in mind that in industry we don't usually model threads or even quote the specific diameter values on a drawing unless they're relating to a non-standard size and/or tolerance. Threads are usually called out on a 2D drawing with the designation and tolerance class. The manufacturer will then manufacture the part in accordance with the relevant standards quoted either on the 2D drawing, or solid model if utilising MBD.

Really, the only time the actual values in the thread files are used is when we're modelling the threads for 3D printing. As I'm sure you know, 3D printing (whether it's FDM, SLA or whatever) is nowhere near as accurate as traditional subtractive machining methods. Because of these inherent inaccuracies we usually need to adjust sizes of 3D printed threads anyway, otherwise we find that the printed parts won't assemble.

Although it is always good to be as accurate as possible you always need to keep a sense of reality. During my Fusion custom threads journey I have come across many discrepancies between various sources of thread data. Some are mistakes and some I can only assume are due to different interpretations of the standards.

I'm quite happy that the NPSM v2 file I have posted in the zip file above is largely correct and the majority of the differences between your figures and mine are not significant. However if you can provide the source of your external minor Ø and internal major Ø values I'd be happy to update my file if I believe they're correct. Alternatively there's nothing to stop you editing the file to your own satisfaction and posting it here!

[user015M86Y]

The source of my data is 15 Gewindetabellen.pdf

The difference in my comments with your file are :

External thread : d3 minor diameter are max

Internal thread : D major diameter are min

If I published my comments it is not for my personal satisfaction but to help you.
I started checking the other files but I'm hesitant to continue because you think I don't keep a sense of reality.

[MRWakefield]

---

@user015M86Y wrote:

The source of my data is 15 Gewindetabellen.pdf

The difference in my comments with your file are :

External thread : d3 minor diameter are max

Internal thread : D major diameter are min

If I published my comments it is not for my personal satisfaction but to help you.
I started checking the other files but I'm hesitant to continue because you think I don't keep a sense of reality.

---

I was thinking about the external minor and internal major diameter discrepancies when trying to get to sleep last night and thought that perhaps I should be using the minimum and maximum sizes instead of using the mean as the basis to calculate from. Anyway I am planning on looking into that as soon as I get some time (hopefully that will be today but I must get on with my day job before I get the sack!).

Thanks for the info, believe it or not I do appreciate you trying to help! However when a value has clearly just been rounded to 3 decimal places (and the difference is in some cases just 0.0001"!) then I don't believe it is worthy of commenting on and obviously makes absolutely no difference at the end of the day, particularly when your figures have been calculated from a metric conversion back into inches. You've done the work in checking the values so if you'd like to implement the changes rather than adding comments in the file you can then post your version of the file here for everyone. It would save me some work that's for certain! If you would like to continue checking and correcting the other files and posting the updated versions here you're very welcome to do so. These files take quite a lot of work to put together and I really don't enjoy doing it (not that all of them were created by me) but if you do then that's great news👍, again it would save me a lot of tedious work!

Anyway, I really must get on with my day job right now!

Thanks again.

[MRWakefield]

I've just updated the zip file in my first post with an updated ISO Metric Non-Std file. I've added M33, M34 and M35 each in 0.5, 0.75 and 1.0mm pitches in both external and internal (so 18 additional thread designations in total). This was prompted by a request in my Custom Thread Utility thread for these sizes. Usual caveats apply regarding errors etc!!