Pipe Unions, Fittings, Standard Dimensions, CAD

[MEinThailandParticipant @meinthailand]

Are there any published standard dimensions for pipe fittings as used by model engineers? Things like pipe unions, union nuts, nipples, olives with their appropriate pipe diameters and thread sizes. Also, various companies offering such fittings have different threads for the same size fittings, for example 1/4 X 32, 1/4 X 40 TPI – is there any preference or standardisation here?  Any data would be much appreciated and I’m dreaming, I know, but CAD drawings would also be terrific.

[David George 1Participant @davidgeorge1]

RS components have data sheets with all the dimensions IE Enots fittings

https://docs.rs-online.com/a938/0900766b810f3410.pdf

If you go to the Enots web site you can search for parts ie olives and select and download cad drawings.

norgren-embedded.partcommunity.com/3d-cad-models/sso/360501-universal-tubing-sleeve-suitable-for-nylon-metallic-tubing-imi-norgren?info=imi_precision%2F3_fittings%2F36_series%2Ftubing_nuts_sleeves%2F36_0501.prj&cwid=2897

Other manufacturers may have the same options.

David

 

[John HinkleyParticipant @johnhinkley26699]

Have a Browse on the Traceparts site for “Pneumatic fittings”  There you will find all manner of Imperial fittings in the sort of sizes that you’re after, in more CAD formats than you can shake a very big stick at.  You may have to register to download, but the resources are enormous and worth it, in my opinion.  (It’s free to register.)

John

 

[MEinThailand]

On 12 April 2025 at 02:20 MEinThailand Said:

Are there any published standard dimensions for pipe fittings as used by model engineers? Things like pipe unions, union nuts, nipples, olives with their appropriate pipe diameters and thread sizes.

For fitting used on models (as opposed to around the workshop), I am not aware of any standard. Too many variables.

[JasonBModerator @jasonb]

As Charles says they do vary a bit between makers od ME fittings. I doubt you will find CAD files of these type model engineering fittings

There was an article in ME a year or so ago that had a table of sizes if you wanted to make your own nuts and nipples for each of the common copper pipe sizes. The only thing you really need to watch is if connecting to a commercial fitting is the TPI, otherwise the rest of the dimensions work OK. Mainland Europe would mean a change to metric fine and metric hex sizes a sthat is what the suppliers there such as Knupfer sell.

[noel shelleyParticipant @noelshelley55608]

Whether the ME threads can be called standard is open to debate, and which one to use for a given job. The 2 common standard pipe threads that are small enough are 1/8″ and 1/4″ BSP but there are the 26TPI, 32TPI and 40TPI thread series,or metric. Don’t get Cycle 26tpi and Brass 26tpi mixed up there not QUITE the same, 60* and 55* thread angles. There is some info on metric threads for use in model engineering in the metal workers data book that might be helpful. If working to a drawing then the thread to use is usually specified. Best to write down little gems as you find them in a book and refer to it as need be. Good Luck. Noel.

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