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February 19th, 2010, 03:00 PM
Its me again....:D

I am looking at how to insert accesories at/into Bauer 200E 8 milimeter OD pipe, such as Moisture Plug which is using 1/4" NPT female thread.

First I must explain that I am a pure dummy when it comes to fitting and threads. With metric and imperial fittings here and there, I am lost.:dork2:.

I am studying Swagelok fittings because as Craig explained that Bauer uses Voss fittings, which there is no Asian dealer listed in their website, let alone for my country.

So I must use Swagelok, there is a distributor in my country and so easy to find in the USA.

My question is about a fitting from Swagelok called Tube Adaptor. I can use this family of fitting to convert 8mm pipe to 1/4" pipe. Now comes the stupid questions :

01. Do I still need to use Swagelok twin ferrule on a Tube Adaptor ?
Attached is what Tube Adaptor looks like.

02. Swagelok has single ferrule and twin ferrule for anti-leak compression on their tubes fitting. I want to know if their tube fittings like Tee or elbow, are they specific to single ferrule/twin ferrule ...or...they will accept both ?

03. Is the female cavity ( its tapered right ? ) where a ferrule is compressed, are they the same shape or angle for different brand compression fittings ?

04. Assuming the threads are the same, can I use say Swagelok nut on a Voss compression fitting ?

I am asking Item 3 & 4 because if my Voss ferrule need to be replaced I want to use other brand of ferrule in emergency.

Thanks very very much guys...


February 20th, 2010, 06:16 AM
Hydraulic steel fitting have no place or use in breathing air compressors and that includes these Voss fittings. There is only one reason they are used: There cheap.

Over time the zinc passivation coating will breakdown and rust will begin. Why Bauer use steel fittings into an expensive filter tower? It saves about $20. However once the corrosion starts it also breaks down the anodizing in the aluminium filter thread and to replace the filter itself will cost you considerably more. Iain Middlebrook

February 20th, 2010, 06:25 AM
My take on this would be to use the Swagelok stainless steel fittings only and on everything. They are 316 stainless and will last a lifetime of your compressor.
Don’t ever mix nuts and ferrules with different manufacturers ever, chances are the nut will not fit the fitting body as each brand has its own thread, pitch diameter and length and as important the angle and sealing edge of the ferrule is also very different. But even if you do mix fittings nuts and olives any engineer worth his salt will rip them out and bill you.

For stainless steel fittings Swagelock are 100% fully 316 and easy available worldwide. Other vendor such as Parker have an A-Lok fitting that is dimensionally the same as Swagelock and will interfit but are only 98% good.
Parker also make a range called CPI (a single ferrule type) and a SAE type fitting.

Granted there are other brands and overseas manufacturers that make OK copies, but far more that make poorer. But for the small number of fittings you need use Swagelok.

To be specific with your compressor photos would be very helpful I don’t think the tube stub will resolve your assembly. Iain Middlebrook

February 20th, 2010, 02:53 PM
Thanks very much Iain. Fittings is something I do not touch ever, since I only maintain the compressor , but never need to plan to disect the air line/pipe until now. Due to the fact I am thinking to insert USA type/sourced after market accessories.

I understand the galvanic corrosion due to voltage differential potential of different metals in my line of work looking after clients yacht. Aluminum is never my favourite alloy. I have seen older Mariner where the valves ( in/out) simply jammed on cylinder heads due to steel corossion on aluminum cylinder heads. So goes a US$400+ cylinder head just to replace a US$120+ sets of in/out valves.

I once attended a Bauer tech seminar conducted by Bauer Asia ( Singapore ) and the senior tech told me that approx 70% of Bauer expensive damage in Asia is due to corossion.

Aluminum mix with steel or even stainless steel is something I will avoid for salty wet environment. I can create a hole in an aluminum boat simply by throwing a small rod of metal of higher nobelity than aluminum in a boat wet bilge.

Its just like television color standard, British and German and most of Asia has PAL, the French has SECAM, a variant of PAL. While the US has NTSC 3.53 and 4.43. It drove me nuts a long time ago. Now as I am looking at threads, I came upon BPS parallel thread , BSP taper, ISO XXX???, Withworth = BSP, NPT, JIC and so on...man, I felt I am so dumb about it.:dork2:

I am not a fan of NPT because it uses Teflon tape. I like compression fitting for its easy positioning & reliable no-leak when disassembled and re-assembled , plus no debris from the teflon tape that will get "cut" for sure on NPT type thread upon installation.

I am asking this Swagelok question is because I am ordering from August Industries their 33" filter tower and it uses a 1/4" female NPT port, while the P41 Bauer uses BSP 3/8" male and 8mm OD SS pipe. The other accesories I intend to order are also all NPT 1/4". In fact today I just realized that my soon to come Keller digital pressure gauge from Swiss uses G 1/4". I thought G 1/4" is NPT 1/4"...:dork2: but that is not true, it is BSP parallel thread 1/4" with no taper. So, Swagelok gauge adapator G 1/4" female to 1/4" male NPT is what I must get. I am so confused with planning to install things that I do not have on hand to try.

What I usually do is bring the stuff I need to a fitting shop. Shop try physcially to find the right fittings...got it ... and..end of story. Now I am shopping via catalog for things I do not really understand, it drives me kind of nuts and I can't buy something for use in 207 BAR service when I do not see proper technical specification.

Language translation is also driving me nuts. Voss calls a ferrule in their English catalog as cutting ring. Swagelok call it ferrule. Voss call a pipe as pipe, Swagelok call it tube. Voss name some part as stud xxxx, Swagelok call it male xxx.:D

Some seller call imperial size as fractional, while others call it inches. Some call BSP as Withworth or some extension of BSP???. Some size is ISO and in some size they call it UNF. Understanding the terms alone is driving me crazy. Machine thread decribed as inches and the pipes as MM ( millimeter )....:confused:.

BSP and NPT is like 5 degrees difference, how do I tell such small difference in thread angle, unless NPT is taper..

So all is interensting....:D:D

Thanks again.

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