Metric Pipe Threads

[Wayne Mo]

Are there such things as metric pipe threads? I removed what I thought was a standard 1/8 pipe thread grease fitting but a new one I had did not seem to interchange. I wondered if the one I removed was a metric! It came off a late model backhoe. I know there are machine screw threads standards for metric and usa but never heard of a metric pipe thread.

 

[souNdguy]

There are metric zerks hanging in napa and TSC??

Soundguy

 

[Dell (WA)]

Wayne........yes, there are metric greeze zerks.........Dell, former BMW mechanic

 

[TheOldHokie]

(quoted from post at 21:14:03 12/13/07) Are there such things as metric pipe threads? I removed what I thought was a standard 1/8 pipe thread grease fitting but a new one I had did not seem to interchange. I wondered if the one I removed was a metric! It came off a late model backhoe. I know there are machine screw threads standards for metric and usa but never heard of a metric pipe thread.

I am not aware of any metric taper pipe thread standard although some proprietary applications may exist. British Standard Taper Pipe Threads (BSPT) are used extensively in Europe, India, Asia, etc. They are not metric but they do not interchange with National Taper Pipe (NPT) used in the US. In particular the nominal 1/8" pipe fittings look nearly identical:

1/8" BSPT = 28 TPI, 55* thread angle, .383 Major Diameter, 3/4" taper per foot, rounded roots and crests

1/8' NPT = 27 TPI. 60* thread angle. .405 Major Diameter, 3/4" taper per foot, flat roots and crests

You need a good thread gage to make a definitive identification.

There are also ISO (DIN) standards that are basicly BSP and a host of straight thread variants (no taper).Here's a pretty good reference if you don't have a copy of Machinery's Handbook handy :wink:

Pipe Thread Standards

TOH

 

[MIDennis]

Yes!! They go on metric sized pipe. When we first started filling European shipping tanks it was a disaster. We ordered a dozen metric pipe nipples and cut them in half and welded USA nipples on the other end to make adapters. When our international company wanted to standardize the electrical community, the metric conduit boxes would not connect to USA conduit. Isn't it a wonderful world we live in.

 

[Bob From Paradise]

This site has a lot of good information about metric fasteners.
Main page below.
http://mdmetric.com/

Chart on pipe comparison.
http://mdmetric.com/tech/pipecomp.htm
BSP/USA pipe O.D. comparison chart

 

[Tim PloughNman Daley]

Wayne.
Absolutely. They've been around for a long time. Brtish. JIS. ISO. DIN. Others have already answered your question, but here's some history. We live in a "metric" world. Back in the late 70's/early 80's we (USA) decided to become a part of the world economy and the car and truck prints we got began showing up in metric. We had to be ISO to be competitive. Granted our CNC machines and all of our gaging was in inches, so we had to convert the prints back to inch format to manufacture. Now, it is rare to see a print in inch format at all. Most machines and programs are all done in metric as well as gaging. Confusing? Does everyone know what and how big a micron is? *Answer below. Ironically, when I go to work on my Ford or Chevy truck, I need a 1/2 inch wrench in one hand and a 10mm in the other. US couldn't quite make the complete changeover. Now pass me a pint, er, liter, er, quart, oh heck give me an old long neck Strohs beer I have a headache!!!

Tim "PloughNman" Daley
*9N653I* & *8NI55I3*

*Question: How big is a micron?
Answer: .00003937"

 

[Steve MI]

In easier terms does this make it about 26 microns to a thousandth? Deal in microns but so completely that never think of thousandths anymore . Retrained to well

 

[Pooh Bear]

(quoted from post at 21:46:49 12/14/07)

*Question: How big is a micron?
Answer: .00003937"

25400 microns = 1 inch.

Anyone here remember milli-microns ??

Pooh Bear