Like it says, I'm looking for a bit of advice on circular hollow section tube, CHS. I have been asked to make a couple of C-stands from scratch; these are photographic stands used for lighting, reflectors, etc. They will be mostly used inside. Pic below.
As can be seen, the tubes fit inside each other for highering and lowering the stand, and for rotating the legs around the base (The legs fold away). I have never worked with CHS much, so would like to know if the tolerances given below would be adequate for smooth rotation, one inside the other, before I order. (I don't know what the plus/minus tolerance from nominal would be on either O.D. or I.D. of either of these tubes).
CHS 33.7 O.D. x 3mm wall (Outer tube). Obviously 33.7 minus 6 gives an I.D of 27.7 mm, in theory at least.
CHS 26.9 O.D. x 3mm wall (Inner tube).
So 27.7 mm minus 26.9 gives a clearance of 0.8 mm, divide by 2 gives 0.4 mm around sides of the inner tube, in theory.
Would this work okay in practice? Or would the plus/minus tolerances of both tubes be high enough to cause an interference fit, or be too tight?
I know the obvious thing would be to get two samples, but I have to make quite a journey to pick up the samples, so if they don't fit, it's a wasted journey.
Any help from those who work with CHS would be greatly appreciated.
As can be seen, the tubes fit inside each other for highering and lowering the stand, and for rotating the legs around the base (The legs fold away). I have never worked with CHS much, so would like to know if the tolerances given below would be adequate for smooth rotation, one inside the other, before I order. (I don't know what the plus/minus tolerance from nominal would be on either O.D. or I.D. of either of these tubes).
CHS 33.7 O.D. x 3mm wall (Outer tube). Obviously 33.7 minus 6 gives an I.D of 27.7 mm, in theory at least.
CHS 26.9 O.D. x 3mm wall (Inner tube).
So 27.7 mm minus 26.9 gives a clearance of 0.8 mm, divide by 2 gives 0.4 mm around sides of the inner tube, in theory.
Would this work okay in practice? Or would the plus/minus tolerances of both tubes be high enough to cause an interference fit, or be too tight?
I know the obvious thing would be to get two samples, but I have to make quite a journey to pick up the samples, so if they don't fit, it's a wasted journey.
Any help from those who work with CHS would be greatly appreciated.