The Mother of All Inventions?
So these heads had been cut before I resurfaced them.
Leaving the fire-ring clearance too tight.
I didn't have a fly-cutter for my mill that would work, so...
My dad whipped up this gizmo to solve the problem.
He chuckled & told me to tell John Hove there's more than one way to blister up your hands workin' on your scooter.
He got 'em though & they are pretty nice.