Minimum wall thickness for stainless steel tube

RJSakowski said:
With both internal and external threads fitting within the 1mm wall thickness, you will want to use a custom thread. For more or less equal wall strength, the pitch diameter will need to be around 12mm.

I would use something like a .5mm pitch which would have a major diameter of 12.36mm and a minor diameter of 11.71mm. Going to a 1mm pitch would yield a major diameter of 12.65mm and a minor diameter of 11.54mm.

This would be for perfectly formed threads. Cutting tools with a radius smaller than the standard thread profile will produce slightly thinner walls.
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Hi Robert,

Your suggestion sounds interesting. I'm sending you couple sketches of the connected tubes. Hope this illustrates my intent. The idea is to connect the two tubes via thread. My concern is the wall thickness and that could it handle threading. I don't want the wall to collapse during threading of the two tubes. Another thing I only need 2 to 3 threads. The idea is really just to connect them. There is no high pressure going through. The only other concerns is the frequency of the usage. I do anticipate high frequency. hundreds of usage.
 

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tgun829 said:
Hi Robert,

Your suggestion sounds interesting. I'm sending you couple sketches of the connected tubes. Hope this illustrates my intent. The idea is to connect the two tubes via thread. My concern is the wall thickness and that could it handle threading. I don't want the wall to collapse during threading of the two tubes. Another thing I only need 2 to 3 threads. The idea is really just to connect them. There is no high pressure going through. The only other concerns is the frequency of the usage. I do anticipate high frequency. hundreds of usage.
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If you are planning to connect two tubes of the same O.D. and I.D. via a threaded joint, what I have proposed is the the best option. There are numerous exaqmples of this type of threading in optical devices. The key is a fine pitch thread. Were I doing this, I would probably single point thread, the reason being that you can maintain concentrixcity, something that is difficult to do with a tap and die. The next best option would be the 1/2-40 tap and die from one of the industrial suppliers. They should set you back around $70 -80. You could start the thread with single point threading and finish with the tap and die as well.

To support the tube, I would make a plug for threading the O.D. and either a collet or collar for threading the I.D. These will prevent the tube from distorting under threading pressure. I would also recommend more than two or three threads, especially if you plan on multiple assembly/disassembly's.
 
Robert
Do you know manufactures who can work with me to design and manufacture prototypes? Thanks.
 
tgun829 said:
Robert
Do you know manufactures who can work with me to design and manufacture prototypes? Thanks.
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How many thousands of parts do you need? :grin: These would be a good fit for my equipment, I can do small quantities. 303 stainless?
 
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