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Thread Specifications

Thread Specifications

Thread Specifications

Dear Folks;

I have all kinds of information on how to properly specify an internal thread on a drawing but not so much about external threads.

On an internal thread I can specify the standard tap drill size required to produce the specific thread.

When I specify UNC and UNF external threads on the end of a shaft is there a corresponding set of standard diameters that I could call up to produce commonly used UNC and UNF external threads

Right now I specify only the size the type of external thread required and no other information. Perhaps this is the proper way to do it but I would like the input of those who have to make the threads so I can  do a better job of specifying them.

Best Regards

Adrian D.

RE: Thread Specifications


I have a freeware program that might help you.  It displays detailed information for 192 of the more common screw threads, including UNC,UNF, UNEF, UNJ, ISO, NPT, and ACME.  Data is there for internal and external threads.

go to www.winsite.com and search for the program "ME Threads".

Mike Rainey

RE: Thread Specifications

Dear Mike;

Thanks for the download link. Its exactly what I was looking for !

Best Regards

Adrian D.

RE: Thread Specifications

Hi Mike,

Yeah, looks handy. But I'm just a dumb electrical guy looking to learn a bit about other things, so...

What are the two horizontal rows of data labeled, say, 2A, 3A, and 2B, 3B? I notice they change with thread type selection. Maybe a small 'Help' button could describe the display format.

Also, a small formatting issue - the % box gets cut off at the bottom, and the TAP DRILL heading on the other box gets cut in half by the 'Drill' and 'Diam...' headings.

I'm running Win2k, 1280 x 1024.

Good work,


RE: Thread Specifications


Thanks for the feedback.

The designations 2A, 3A, 2B, 3B, etc. are industry-standard terms related to class of fit for internal and external threads.

In a nutshell:

2A is an external thread with a "medium" fit which would be for general applications

3A is an external thread with a "close" fit which would be for critical or high-strength applications

2B and 3B follow the same theme but specify internal threads.

Metric and ACME threads have different alphanumeric designations, but the idea is the same.

UNJ are high-strength (controlled root radius) threads and only have class 3 specs - they're used a lot by the aerospace industry.

I'm working on Help files - writing them can be as big a job as the program.

As for the formatting issue - I'm looking at my program on a 15" laptop 1024 x 768 screen with no problem.  The window takes up about 2/3 of the screen.

Do me a favor - download http://bellsouthpwp.net/r/s/rsnmar/MachiningBeta1.zip and run the program.  Click on the Threads option and you'll see the same threads program in a more compact display.  Let me know how that one looks.  You might like that program better anyway - lots more stuff for a dumb electrical guy to learn  

              Mike Rainey

RE: Thread Specifications

Hi Mike,

OK, ran MachiningBeta1, and the symptom is the same, except worse!

1. In the main window that first appears, *all* the box headings have their bottom few pixels cut off.

2. when I open the 'Threads' window, the same thing happens i.e. all headings have their bottom shaved - but wait, there's more - the group headings (MAJOR DIAMETER, PITCH DIAMETER, etc) have the same symptom, except that they lose almost the entire bottom half of their characters.

Ive written a few programs in Visual Basic dot Net, and this is the sort of thing that happens when heading (text) boxes either overlap, or are too small for the font size (I can't remember which).

I dropped my screen resolution back to 1024 x 768, but the symptoms were the same.

I'm using a desktop system with a Matrox Millenium G550 video card. I'm only running a single 21" screen. I use many other CAD programs, some of which will really find any bugs in the hardware (e.g. Protel pcb s/w), and have zero problems. I'm not familiar with IBasic (I guess it's some sort of visual development enviroment), but the symptoms look very much like my description of the dot Net characteristic.

If it's of any use I could capture the screen image and email it to you.


RE: Thread Specifications


Would appreciate very much a screen image showing the problem.

I've run the beta on the following systems, at various resolutions,  with no evidence of the problem you describe:

Dell 15" UXGA laptop with ATI Radeon 7500 card   Windows XP Home

PC Clone, Samsung 19" Syncmaster, with Matrox Millenium G550 card, Windows 98SE

HP Kayak, HP 19" monitor, with Oxygen Labs (?) card  Windows NT4.0

HP Kayak, HP 19" monitor, with Oxygen Labs (?) card  Windows 2000

One guy did give the following report:

... the labels are partly obscured by the data windows. Probably an artifact of my video driver.  I'm at 1600 x 1200, Dell laptop Inspiron 8000 nVidia card...

You've given me some ideas.  Could you let me have your email address so I can send you some things to try as I come up with them?  Thanks.

People like you are a godsend for programmer wannabees like me.


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