GAUGE , is one inch thick of steel or metal. So, take this one inch thick of steel sheet and cut it into 12 equal thickness sheets , you get a 12 gauge steel sheet. Similarly, take this one inch thick of steel sheet and cut it into 14 equal thickness sheets , you get a 14 gauge steel sheet. and so on . So, a 12 gauge steel sheet is thicker than 14 gauge , 14 is thicker than 16 , 16 is thicker than 18 and so on. Wrong!!! See my discussion on this...
2.10mm thk
4mm sheet metal falls 24 gauge and 25 gauge. 24 gauge sheet metal is 3.175mm (0.125") thick, and 25 gauge sheet metal is 6.35 (0.25") mm thick.
if it's 14-gauge then it's 14-gauge.
Assuming this is a firearms question- the 14 gauge shotgun is very rare today. The bore diameter is smaller than a 12 g, larger than a 16g, and runs ABOUT 0.695 inches. That converts to about 17.65mm. If you are seeking to convert wire gauge, or sheet metal gauge to mm, please repost with that information.
20 gauge is equel to 0.8mm
Thicker.
14 gauge is thicker than 16 gauge.
13
Pipe and sheet metal of various types use different scales. For 14 gauge metal, the thicknesses would be (in inches): 0.0781 inches - US Standard Gauge 0.0747 inches - Sheet Steel 0.079 inches - Galvanized Steel 0.0781 inches - Stainless Steel 0.083 inches - Tubing Thus, 14 gauge pipe would nominally be 0.083 inches thick.
16 gauge is smaller than a 14 gauge. You can buy a stretcher and stretch the hole.
14 gauge is larger than 16 gauge. 14 gauge is 1.6mm (0.06") and 16 gauge is 1.29mm (0.05").