BA (British Association) Screw Thread XML Data Table

[agordon]

Some folks, particularly model engineering folks might be interested in the British Association thread data for use in Fusion360. It will automatically allow BA threads to be added from the MODEL/CREATE/Thread command ribbon.  The data table contains both internal and external form data.

The file can be downloaded using the link below. Tested working with the 11/2016 update.

To use the data, it has to be placed in the thread data folder ... can vary from machine to machine. On my non-networked system, it was found as follows (Nov-2016 location, it can change!):

c:\Users\[your user name]\AppData\Local\Autodesk\webdeploy\production\[strange alphanumeric string ... if more than one, use the most recent]\Fusion\Server\Fusion\Configuration\ThreadData\

The RED parts of the address above will vary by user and machine.

I have not tested this with the CAM side of F360. The table does have the correct tapping drill info entered, however since I've never used the table in a CAM operation, you try it at your own risk!

[HughesTooling]

@agordon Thanks for taking the time to do this.

One thing to note, the folder moves with each update so you'll need to move the XML file every update.

I took a look and it looks like you have some settings wrong. Here's the modeled thread for 2ba, male and female, the form's wrong and the clearances are incorrect,

You might want to look at the BSP XML for a reference as it has the similar form, angle's different but crest is filleted, example below.

Mark

[agordon]

Hi Mark,

Really appreciate you taking the time to look at the thread table in detail!  My purpose was largely to help me creat a 3D model of a steam loco I am building to help identify clearances and clashes.

I have updated the table and added tolerances on the bolt side of the table for "close fit" (now that BA is not a supported form, finding BS thread data info is not easy!).

Also, I looked closely at the BSP XML table and changed everything in the BA table inherited from the ANSI data, to match the BSP info: still have a square crest and root ... 

I'll hold off uploading the revised table until I have sorted out the rounded crest and root issue ..

Any suggestions?

[HughesTooling · Accepted solution]

Just found this in another post. I tested on your file and it works! I've attached your modified file.

Define thread shape for your customize thread: add "<ThreadForm>0</ThreadForm>" under the <ThreadType>, 

        0----trapezoid; 1----sharp; 5----square; 7-----withworth

     if you don't add this, default shape is trapezoid

Mark

[agordon]

Thanks Mark!  Great teamwork!

I am not able to edit the original post in this thread, so I hope folks are aware that they should download your version, not the earlier version!

[agordon · Accepted solution]

I'm grateful to Mark (HughesTooling) for reminding me that I had not uploaded the final version of the BA screw thread XML table.

Since my first post, my quest to develop a selectable BA thread form within F360 has turned into a norse epic ... 

After a lot of searching around, I did find the external tolerance tables for BA Normal and Close thread forms from BS93 (grateful thanks to Ring and Plug Gage Company).  Excel file attached.  

With the tolerance tables, I was able to then edit the BA screw thread data table to include the Normal external thread tolerance (0-16BA), and Close (0-10BA).  Normal and Close are the BSI terms used for tolerances applied to this thread form, BS93:2008 doesn't use numbered ANSI tolerance format!

With Mark's help, the thread does exhibit the correct crest and root form (Whitworth).

Hoping I've now uploaded all that is needed by model engineers to use BA threads in F360!

[Stuart-H]

how about ME threads constant pitch in 32 tpi and 40 tpi they are whit worth form as well sorry for a cheeky ask

question about BA note i use them down to 12BA on a regular basis i always was led to believe they are a metric based form not whit 

[HughesTooling]

@Stuart-H

I was told the same but looking at the info here it doesn't seem to really be metric or English! 0BA is 6mmx1mm but none of the others fit, probably an example of design by committee.

Mark

[agordon]

---

@HughesTooling wrote:

@Stuart-H

I was told the same but looking at the info here it doesn't seem to really be metric or English! 0BA is 6mmx1mm but none of the others fit, probably an example of design by committee.

Mark

In my digging around, I came across a lot of info on the BA thread form.  The best description I found is copied below (source sizes.com BA Thread Information😞  

"In 1884 the British Association for the Advancement of Science adopted a thread form and series, primarily for use in precision equipment. It was inspired by one used in the Swiss watch and clock industry, and was formerly sometimes called the Swiss Small Screw Thread System; but is now just referred to as the BA series. Like the Whitworth thread, it has a rounded root and crest, but the included angle is 47.5° and the radius was originally 2/11 (0.1818…) times the pitch, but at some later point was changed to 0.18083. The gauge numbers and pitch are related, roughly, by pitch = 0.9 to the power of the gauge number.   

Despite the date of origin and the British sponsorship, the BA is a metric series. Not only is it based on the meter, but the thread frequency is specified in terms of round numbers in the pitch sequence, with threads per meter allowed to fall where it may.   The British Association thread played a role similar to that of the ASME series in the United States, that is, it filled in sizes below a quarter-inch. The sizes most used were the even-numbered ones between 0 and 10, inclusive. The very small sizes, from 17 up, were rarely used.   

In 1966 the BSI declared the BA screw thread obsolete; its place was taken by ISO screw threads."    

Tony

[agordon]

---

@Stuart-H wrote:

how about ME threads constant pitch in 32 tpi and 40 tpi they are whit worth form as well sorry for a cheeky ask

---

Done (I really should get a life, but also realized that Evan's does use the ME thread in his Super Simplex design).  I wasn't able to put both TPI forms into the same table ( am sure it can be done ... suggestions Mark?).  The info is in a new thread ...

Incidentally, why would you ever use these threads?  Since you cannot purchase nuts, bolts or studs, they are purely threaded part assembly thread forms, and there are other fine thread forms in the UNF and UNF special range that will work as well.

[Stuart-H]

Thanks for the info

as to ME threads bolts/nuts I make them ,dare I say on a manual lathe ,my only CNC is one of my mills

i have a full set of ME t and d 

but it would be nice ( I hate that word used with day ) to model them when redrawing the very poor mistake ridden drawings sold today especially for walcherts valve gear Stevenson's launch and loco link are bad as well, yes I do use the simulation software as well

main use for me for ME threads is for boiler fittings especially nipples for hollow stays 

thanks again for your work with the BA stuff

[agordon]

---

@Stuart-H wrote:

Thanks for the info

as to ME threads bolts/nuts I make them ,dare I say on a manual lathe ,my only CNC is one of my mills

i have a full set of ME t and d 

but it would be nice ( I hate that word used with day ) to model them when redrawing the very poor mistake ridden drawings sold today especially for walcherts valve gear Stevenson's launch and loco link are bad as well, yes I do use the simulation software as well

main use for me for ME threads is for boiler fittings especially nipples for hollow stays 

thanks again for your work with the BA stuff

---

Did you find the thread with the full ME thread data?  Download Mark Hughes version: he has combined the two files I created into one table, much more convenient!  Just search on ME threads.

[Stuart-H]

Thanks

[andy.bowdidge]

Does anyone know how to include this file on the Mac version please?

I do model engineering an most of my work is in BA and ME threads.

Thanks

Andy

[HughesTooling]

Hi Andy

This link should help.

https://knowledge.autodesk.com/support/fusion-360/troubleshooting/caas/sfdcarticles/sfdcarticles/Cus...

Mark

[andy.bowdidge]

Thanks

Those folders are hidden on a Mac so had to mess around to get them visible.

All sorted

All the Best 

Andy

[Anonymous]

Have used these data tables before, succesfuly and happily (thank you @agordon ) but when I tried to re-install them in my Win10 machine encountered a problem ...

Got as far as:

AppData>Local>Autodesk>webdeploy>production>strange alphanumeric string

and then instead of:

>Fusion>Server>Fusion>Configuration>ThreadData

I am getting:

Api>Python>packages>adsk>defs ...etc, etc

It would appear that something has changed and the original instruction are no longer working...?

Can someone help me, please?

[Anonymous]

panic over and problem solved,

see:

https://forums.autodesk.com/t5/fusion-360-design-validate/thread-data-directory-where-is-it-nowadays...

un-installing and re-installing Fusion client repaired corrupted App data folder and everything is back to normal

[HughesTooling]

@Anonymous @agordon @andy.bowdidge @Stuart-H  Has anyone tried to create a modelled thread with a Whitworth form lately? When I try I just get a trapezoidal form without filleting of the points.

Thanks Mark

[MRWakefield]

I've just checked with a BSP thread and it looks ok for me. Is it one of the standard thread files or is it a custom thread you're having problems with?