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Gallery, Projects and General => How do I?? => Topic started by: DavidA on January 03, 2016, 03:37:22 PM

Title: M2 thread
Post by: DavidA on January 03, 2016, 03:37:22 PM

When cutting BSF threads there is a formula that allows one to derive the thread root diameter. This is very useful as it means you can turn a bit at the end of the tread to know when you are down to full depth.

It is Root Diameter = OD - (1.28066/TPI)

Where OD = Outside Diameter
and    TPI  = Threads Per Inch.

My question is , is there a similar formula to carry out the same operation on ISO Metric threads ?

My specific need being to know the root diameter of an 2 MM pitch thread on a 22 MM bar.

Dave.

Title: Re: M2 thread
Post by: awemawson on January 03, 2016, 03:51:21 PM

Dave,

The depth of thread is independent of the diameter of the bar you are threading, so just look up the depth of thread for any 2 mm pitch then subtract it from your bar size. Or use the factor of 0.614

2 mm pitch has a thread depth of 0.614 x 2.0 = 1.228

http://www.newmantools.com/tech/threadm.htm

Title: Re: M2 thread
Post by: DavidA on January 03, 2016, 03:55:21 PM

Andrew,

Thanks, that was exactly what I wanted to know.

Dave. :thumbup:

Title: Re: M2 thread
Post by: lordedmond on January 04, 2016, 02:34:03 AM

David

I just deduct the pitch from the dia

Ok for tapping drill and single point

See ref in above link for 12 mm 2mm pitch yes that's a standard one but in your case the root dia is 20mm

Stuart