[Newbie] Advice machining stainless steel.

Being a guy that has machined and welded a lot of 316 SS, be ready for a learning curve. Make sure you purge the inside of that tube with argon before you weld the outer circumference or else it will probably get really ugly on the inside. Make sure you practice TIG a bunch before you weld your part.

Keep in mind that I am not trying to scare you off, but I am encouraging you to exercise some due diligence before you start on your finished part. Practice WILL pay off. Keep in mind that TIG welding thin stainless tends to make the stainless warp into what almost appear to be totally new shapes from what you started with. The flat disc at the bottom will likely need to be kept flat, so be sure to weld the two pieces together before you take your finishing cuts.
 
Being a guy that has machined and welded a lot of 316 SS, be ready for a learning curve. Make sure you purge the inside of that tube with argon before you weld the outer circumference or else it will probably get really ugly on the inside. Make sure you practice TIG a bunch before you weld your part.

Keep in mind that I am not trying to scare you off, but I am encouraging you to exercise some due diligence before you start on your finished part. Practice WILL pay off. Keep in mind that TIG welding thin stainless tends to make the stainless warp into what almost appear to be totally new shapes from what you started with. The flat disc at the bottom will likely need to be kept flat, so be sure to weld the two pieces together before you take your finishing cuts.

If I made the flat disc 0.25" or 0.5" thick where it contacts the tube, would it still warp? I want to make this as easy as possible and would rather make my finishing cuts before welding if possible. Thanks for the advise!
 
You would probably be okay at .250" as long as you don't get the heat too high. With some experience, you could probably go down to about .180 or .200 and be okay, but being new to this, you might want to stick to a little bit thicker.
 
You would probably be okay at .250" as long as you don't get the heat too high. With some experience, you could probably go down to about .180 or .200 and be okay, but being new to this, you might want to stick to a little bit thicker.

I'll add more material then, thanks.

Any suggestions on what cutters to use when milling?
 
You might also consider a solution where the pieces screw together, so the screen is held in place by a "nut" that screws onto the bottom and presses it against the tube...assumes you have a lathe that does threading... This might aid in cleaning it later as well.
 
Can you think of a better way to attach the thin piece to the tube, even if it's a major design change?
Not without knowing what it does nor the loads it may need to withstand. The manufacturing method would be dependent on the number of parts required, if you are a hobbyist making only a handful and have no deadline just rough the parts, weld them then finish machine after welding.

If thousands of parts per month are required with a strict time constraint injection molded plastic is the answer the original manufacturer came to. Also Electron Beam welding creates far less distortion.
 
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For some reason I lost track of this thread for a while. When working with stainless, especially 316, I stuck with carbide cutters almost without question. HSS will work, but resharpening frequently will become the new normal. Make sure to use lots of coolant no matter what you use for a cutter.

I also like dave_r_1's idea of threading the bottom disk onto the tube. No warpage to worry about if you do it that way. You might have to make the bottom end of the tube a little thicker for that to work, or you could just use a very fine thread so that the root of the thread does not get so deep in the tube itself.
 
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