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[Waiex191]

Hey all,
I have these two blue anodized aluminum fittings that I need to adapt to.  This is a Brauniger Alpha MFD and was made in Germany.


So the threads measure as 0.9 metric, or 28 SAE.  The body is somewhere between 9 and 9.5mm.  Is this some sort of super secret thread size? 


I had 3D printed an angle adapter but I can't get a tap to make those threads.

[ribbert]

Does your local hardware shop have one of those merchandisers with a display board of male and female threads so you can screw your sample in to identify your thread?

One of the great things about the Metric system is simplicity, including threads. In fifty years I've never found anything that doesn't simply fall into course or fine (and the right size). I don't recall ever having an issue with weird threads.

Perhaps just take your sample to the hardware shop, if you live in a reasonable size town they will have a specialist nut and bolt supplier, even easier.

Noel

[Millietant]

We have the same Noel, but in the USA I'm not sure if they have metric in a wide range of sizes in hardware stores.

Might need to be an automotive supplies place ?

[red]

Waiex191,

Those blue hose connectors look like USA aircraft fittings, and if so, then they may have Imperial threads (inches-based), not Metric.  Try an aircraft parts place (maybe at a small local airport) and see if they have such fittings.  They also may have taps and dies for those threads available to order.
.

[Waiex191]

We have some metric hardware out here, but just the common stuff.  I've got what I thought was a full metric tap & die set, but I don't have that size.  My internet search for a 0.9 thread has yielded nothing, and it seems that there is no such animal as a 9mm.  Measuring with the calipers across the OD of the threads gives me something like 9.53mm.  If it is an SAE size, the 28 thread gauge also fits nicely, but a 1/4-28 thread is the only size with that pitch.  The 1/4" is significantly smaller than the ~9mm.

Initially I was sloppy and I assumed it had to be a 10mm x 1.0, which was not in my set but seemed like there was some of that out in the world.  I bought the tap.  When I tapped my 3D printed adapter there was no way it fit.

Noel in Connecticut we used to have The Nutty Company, which was an awesome shop.  They had everything.  The closest I've found out here is Fastenal, which is good for the vanilla metric stuff I've needed.

Red, my hobby is aircraft building and I actually live at a small airport with both a maintenance shop and a well equipped EAA hangar!  I am certain they are not aircraft fittings though the blue anodize looks similar. 

[fj1289]

I went through something similar recently - check some of the NPT taps.  Some of them are odd-ball combinations of diameters and pitches compared to “conventional” metric or SAE or even AN stuff.   

[red]

Red, my hobby is aircraft building and I actually live at a small airport with both a maintenance shop and a well equipped EAA hangar!  I am certain they are not aircraft fittings though the blue anodize looks similar.

Waiex191,

We once refurbished an old English Viscount airliner (turboprop).  Everything on that plane was SAE.  Nothing in our usual tooling (Metric or Imperial) would fit, and we had to order every threaded component we needed.  Just a thought.

[Old Rider]

This is a nice tool i got it included when i bought  a tapping set long time ago

[Waiex191]

This is a nice tool i got it included when i bought  a tapping set long time ago

Yep, I have a few of them.  The threads measure both 0.9 metric and 28 SAE.

I've given up on the fittings and am printing my own.  I'll post pictures later.

[Carson City Paul]

Hey all,
I have these two blue anodized aluminum fittings that I need to adapt to.  This is a Brauniger Alpha MFD and was made in Germany.


So the threads measure as 0.9 metric, or 28 SAE.  The body is somewhere between 9 and 9.5mm.  Is this some sort of super secret thread size? 


I had 3D printed an angle adapter but I can't get a tap to make those threads.

It is not uncommon to find things made with a one-off thread size.
The manufacturer will have their own specified taps and dies made for the sole purpose of having to deal directly with them.
Working as a machinist my whole life I have come across bastard size treads numerous times... you may have something like that. 

[Waiex191]

It is not uncommon to find things made with a one-off thread size.
The manufacturer will have their own specified taps and dies made for the sole purpose of having to deal directly with them.
Working as a machinist my whole life I have come across bastard size treads numerous times... you may have something like that. 

Good to know - the alternative explanation was that I was losing my mind!

[Waiex191]

So I tried to print my fitting adapters in PLA.  That stuff doesn't tap worth a damn.  So I went old school and fabricated them out of phenolic.  I did print tools to locate screw holes in both the fitting and the MFD case.


In this next picture I'm using one of the printed tools to drill some #40 holes.  Afterwards I drilled them up to #36 and then tapped them 6-32.


In this picture I've tapped my adapter for 6-32 screws and three 1/8" NPT fittings.  Two are hose fittings for inside the instrument and one is a compression fitting for my 1/4" OD poly tube.


Hoses connected:


And here the job is done.