Tobin Arp Line Boring Machine bits
Tobin Arp Line Boring Machine bits. by PackardV8 » Fri Jan 03, 2014 8:44 pm. Anyone have a source for the cutting bits used in the Tobin Arp TA14, 15 or 20? The $75 each from Sunnen is typical of their tooling costs. The couple of standard bits we have don't look especially complicated, just 3/8" square with the corners rounded.