Thread callout for thread on Japanese (metric?) fitting

[ken1554]

I have a Japanese Teflon fitting which has a thread which measures 1.188" (30.18mm) for the major, 1.078" (27.38mm) for the minor and has a pitch of 14 to the inch or .551 threads per mm. <br>
Does anybody know what the callout for this is or where to find the info?

 

[MikeVV]

Teflon is so soft that you may be able to get the threads to fit several standard forms &lt;grin&gt;.

 

[Baldy]

If I remeber I think the Japanese have their own thread class. I will try to track down how it is classified.

 

[Baldy]

Japanese threads are classified under JIS (Japanese Industrial Standards) similiar to our ANSI.<br>
<br>
You may find more if type JIS or Japanese Industrial Standards in a search engine such as Yahoo or Ask Jeeves.<br>
<br>
I've worked with Japanese threads in the past and getting the standards was tough.<br>
<br>
ROTS OF RUCK!!!<br>
<br>
Mark

 

[Baldy]

Try this

http://www.hike.te.chiba-u.ac.jp/ikeda/JIS

 

[ken1554]

Thanks Mark for taking the time to respond. I'm pretty sure you're correct in saying the threads fall into the Japanese JIS system. What didn't add up to us was that the minor and the major didn't fall on round mm's. But maybe the Japanese doesn't pay any attention to this as does the normal metric screws we're familiar with. I will attempt to track them down through the web site you kindly posted or other means if required. At least I have a path to follow! Thanks again.

 

[TedT]

Be careful that this is not a taper thread! Location on the axis will determine the diameter. Look in the machinery hanbook to explain via figures. You may even find a metric taper thread in a current edition.<br>
Let me know what you decide.

 

[ken1554]

The thread was definitely straight, not tapered. Fortunately, we have been able to get around the call out issue easily because we had to have a quartz part machined which would match the Japanese Teflon fitting. Therefore, on the drawing, we called out the pitch and the diameters needed. The quartz parts are made on a lathe, of course and the thread form is ground into the part by a tool-rest mounted rotary diamond wheel grinder. But having said all this, it still is a shame that we couldn't come up with the actual thread form call out for the drawing. <br>
I suppose if we did have the seemingly obscure call out, it would probably give our quartz machinists fits trying to figure it out. Thanks all for your comments and help, I really appreciate it! Ken