Grommet Split

[nikpalmer]

Hi, we don't use grommets a lot however the nickel plate (steel?) grommets i have tend to split. They are around 3/8" internal, 1" external dia. I use the correct anvil and setter and have used a variety of sized holes. However the male tends to split were the setter peens it over. Normally in two places on the internal circumference. Functionally they are perfect but aesthetically they look poor. It could be cheap grommets or setter. I have also tried one large hit, and many small taps and all in between. Normally the grommet is set in 1 or 2 thicknesses of 8-10oz.

Any advice appreciated.