I've discussed part of these question somewhere else, but realized I have to be more specific about it. I'm new to this site and hope I'm doing the right thing. I'm planning to manufacture gas struts used in kitchen cabinets; therefore, firstly, some guide books or standards about the needed cylinder surface (surface finishing and tolerance) and compatible o'ring and rod seal of this cylinder-piston mechanism would be very helpful.
The gas strut is filled with 6-7 bars Nitrogen and the cylinder have 14mm ID and 12cm length. The piston consists of a steel rod and a plastic piston head. Obviously, there is a rod seal between the rod and cylinder, and an o'ring around the plastic piston head. I cannot use seamless tubes since the end price would not be able to compete with current gas struts. I've been suggested plug draw welded pipes(tubes) in order to eliminate the weld seam inside the tube. How close would the inside surface after drawing be to the desired surface? Is this the most efficient way?