Assistance requested from those that are familiar with DIN38 fittings

[76dave]

What confuses some people (including me, initially) is the fact that BSP fittings are specified by the BORE of the pipe and the actual thread which goes outside the pipe is bigger. Thus, a 1/2" pipe thread has a OD of 0.825" or 20.96mm. Also confusing is specifying the old imperial PIPE by the bore (e.g. 1/2"), while modern metric TUBE is specified by it's outside diameter (e.g. 15mm). The two examples of pipe and tube are virtually the same dimensionally and can be joined in a 15mm compression fitting, using a different olive for the 1/2" pipe. I don't know much about the American system, except it's different to just about everybody else.

 

[ajoeiam]

I see it alot, even on "engineering drawings" for gas turbine lube systems where the piping and associated fittings are simply referred to as DIN38 or similar, to reference the nominal diameter - similar to saying 1 1/2" pipe. Its not a true full spec as it doesn't define the fitting connection, just the nominal size (i.e. 38mm).

And yes, it is correct to say BSPP does not seal on the threads. Needs a gasket. To confuse matters more see this:

View attachment 135647

From the Parker Catalaog 4300 - hard copies of these are invaluable for the reference sections (front or back).

(I normally delete tables and pics but not when I'm referring to them!!)

Reading that info from the Parker catalog one would think that they actually knew something.
That is - - - until you realize that its a huge multi-national corporation that is trying to impose its idea of how things should be.
Anyone that trusts the 'Current use' part of the table is going to be in for a rude shock!!!!!!!!!

So I was looking to just bloody well make a 1-1/2" M BSPP to 1-1/2" M NPT fitting.
Delrin is some $43.28 (CAN) /' , a 660 Bronze runs some $108 (Can) /' and then there's the machining.

Was able to find a couple companies that actually sell the fittings (almost impossible to believe!! and took some digging!!)

So for about 1/3 more than the cost of the Delrin - - - - I have a fitting.

Likely the way to go.

 

[ajoeiam]

What confuses some people (including me, initially) is the fact that BSP fittings are specified by the BORE of the pipe and the actual thread which goes outside the pipe is bigger. Thus, a 1/2" pipe thread has a OD of 0.825" or 20.96mm. Also confusing is specifying the old imperial PIPE by the bore (e.g. 1/2"), while modern metric TUBE is specified by it's outside diameter (e.g. 15mm). The two examples of pipe and tube are virtually the same dimensionally and can be joined in a 15mm compression fitting, using a different olive for the 1/2" pipe. I don't know much about the American system, except it's different to just about everybody else.

Hmmmmmm - - - - learning the difference between pipe and tubing was one of the first things that was a 'have to know' when I hit the metal trades quite some time ago.
It seems that today, at least according to FreeCAD, that pipe is measured just like tubing - - - you know - - - ID + wall - - - - except that pipe isn't with any regular wall measurements. Instead something called a pipe schedule is used. haven't had it confirmed but I'd bet that the schedules at least used to refer to the pressure capabilities of the pipe but that's my guess.

AISI pipe and tubing are really two different beasts - - - - sorta similar - - - but just different enough to bite the unwary.