Oh, another fundamental skill I need a bit of help with... metal snips

[Hofacker]

While we're looking at very fundamental skills I'm having a problem cutting a smooth edge. In the "how to" videos the master craftsman cuts a nice smooth curve around his work piece. When I try that I get a "dink" or " dimple" at every point where I stop to get another bite with the snips. Trying to smooth these little dimples out causes the formed flange to distort. Trying to file them down doesn't seem to be the answer: 1) it takes a LOT of material, 2) it takes a LOT of time, 3) the master craftsmen in the videos don't have the problem. Help!
CRH

[Kyle Boatright]

Take smaller bites. You never want the tips of the snips to go through the material. They leave the dimple (or tear) you're talking about.

[crusty old aviator]

Also, try cutting 1/8" to a 1/4" outside your cutline, then come back and trim the ribbon from your cut line. That helps eliminate distorted edges. Tin snips make the best cuts, with their big, smooth jaws. Aviation snips are fine for roughing cuts, but their serrated jaws require a lot of edge filing to eliminate all the little nicks that can be the starts of cracks in a high-vibration environment. Use a mill (single cut) file for your edge filing.

[FlyingRon]

Kyle has the biggest help. Second, make sure you're using a reasonable tool (as crusty points out). The hardware store "tin snips" generally have enough slop in them to be hard to do anything with precision. Also they make them for cutting straight and different ones for cutting curves left or right. Actually, more often than not I use a air-driven shear these days which really takes little bites as you push it a long (and it's shear is supported on both sides of the cut unlike the hand shears).

[cliffo]

The handles of the nippers are color coded, red, green, and yellow. One is left, one is right and the other straight. As with all tools the quality of them varies along with the price. A journeyman insulator is probably the more proficient in their use, along with heating and cooling installers who do a lot of duct work. Not to be a wise acre, but, there is no substitute for experience and patience when learning these "fundamental skills" !

[Mike Switzer]

Wiss makes the best hand operated sheet metal shears. If you are doing a lot of cutting, depending on what you are doing the electric shears can work fairly well, if nothing else you can do a rough cut with them then trim the final bit by hand. Eastwood was running a sale on theirs a few days ago, that said most of the contractors I know that do a lot of work with steel sided buildings buy the cheap Tool Shop brand from Menards & consider them to be disposable. I cut all the window & door holes in my building with one & it just keeps working.