# New metric threading calculator



## More4dan (Feb 6, 2020)

I’ve used Theoretical Machinist calculators for developing threads for my kitless pens but there was a problem. The calculator as made for Inch based threads and with some work could tricked to give information for metric threads by converting pitch to threads per inch. Great news! They’ve just added a metric thread tool beta version. So, you can specify your metric thread and then convert all the dimensions to Inches with one click. 

It even lets you put in your own specialty threads like M6.4 x 0.5 for those odd spec’d nib feeds. 

It will also give dimensions (min/max) for tendons and holes for threaded connections. 






						Metric screw thread: M Profile calculator
					






					theoreticalmachinist.com
				




Hope this is of some use for the Kitless Makers out there. 

Danny


Sent from my iPad using Penturners.org mobile app


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## FGarbrecht (Feb 6, 2020)

Danny
Thanks for pointing this out.  When you're using the calculator to set up for single point threading, do you use the calculated major diameter for tenon size and the minor diameter for hole size?  Do you add in any fudge / tolerance factors?


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## More4dan (Feb 6, 2020)

You select a tolerance for an external thread and the Major diameter will be the tendon size. The most helpful is then the thread depth for knowing how deep to cut when single point threading.
Select a tolerance for an internal thread and the Minor diameter is the hole size. When making a tap use the Major diameter of the internal thread. 

Danny


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## More4dan (Feb 6, 2020)

On the inch page it describes what the tolerances choices are so you know which to pick. The metric page doesn’t yet have this information. I’m sure a google search could help.


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