Mcmaster

=== Metric round tubes ===
10, 15, 20mm 
http://www.mcmaster.com/#standard-stainless-steel-hollow-tubing/=qe21r4
=== Inch - mm conversion ===
* Small-Diameter Round Tubes—Unpolished (Cold Rolled)
* 1inch = 25.4mm
* OD ---- ------- ------------- ID
* 1/8" ---- 3.18 mm ----	0.0690"	±0.005"	8457K51	
* 3/16" ---- 4.8 mm ----	0.1315"	±0.005"	8457K52	
* 1/4" ---- 6.4mm ---- 0.1940"	±0.005"	8457K53	
* 5/16"	---- 8mm ---- 0.2565"	±0.005"	8457K54	
* 3/8"	---- 9.5mm ---- 0.3190"	±0.005"	8457K55	
* 7/16"	---- 11 mm ---- 0.3815"	±0.005"	8457K56	
* 1/2"	---- 13 mm ---- 0.4440"	±0.005"	8457K57	
* 9/16"	---- 14.3mm ---- 0.5065"	±0.005"	8457K58	
* 5/8"	---- 16mm ---- 0.5690"	±0.005"	8457K59	
* 3/4"	---- 19mm ---- 0.6940"	±0.005"	8457K5
== sa suppliers ==
http://www.stewartsandlloyds.co.za/PriceLists/tabid/103/Default.aspx
http://www.macsteel.co.za/products/carbon-steel-tube-pipe
Category:Cnc
Category:Construction materials