On Dec 12, 9:12*am, Tony wrote:
Do steel tubes have a "seam" like pipes? *If not, is there a real
difference besides the sizes?


There are seamed, seamless, and Bundy tubing which is common in
automotive brake lines. Bundy uses a double wrapped construction which
is then oven treated to fuse the braze coating on the base tubing.
Good stuff for high pressures.
Comment on black iron pipe: any one who has had to thread BI for an
air compressor or NG project lately will note that the product from
China is not perfectly round. Our overseas supplier has yet to master
the finesse that American suppliers apply to the BI seams. I suspect
many pros are using special cutters to chamfer outer edges so that
pipe dies can start a smooth, and continue straight. These days I
always dig out the angle grinder and reshape the cut pipe before
attempting to thread it. Saves time in the end.

Joe