I use JamminSam's grommet tool with excellent results. It also employs the tighten-bolt method like Kentucky Home's, but it was included free along with the grommets in a wrap purchase. I believe he only sends the grommet tool with a purchase. You can't buy one outright.Mike
The Jammin' Sam tool can be assembled for about $3.00 at the
hardware store (it's pictured on his website). It shouldn't be
compared to the the tool sold by MOKD and Chicago Drum Exchange.
At one time, I used the hardware-store variety (works best if
tightened with a small air / impact wrench) but the MOKD version
does a superior job and doesn't risk distorting the grommet.
If I had to install only one grommet, I'd muddle along with the
hardware-store version or use the ball bearing/hammer method.
My MKOD tool has paid for itself many times over.
My .02
MW