Modofied Grind for Coring System
Peter Teubel
>In response to many requests, here's the modified grind for the Kel McNaughton coring tools that I have used. Yes, I've cored bowls on my Jet 1236 (before I got 2 bigger lathes). I originally heard of this grind from Ruth Niles (www.torne-lignum.com) who got the idea from Mike Mahoney. The top is the original grind and the bottom is my modified grind. I simply created a "V" scraper from a straight scraper.
I tried it out and it works great. I have since compared the original grind (borrowed a coring set from a friend) to the modified grind...side by side tests...and found that the modified grind is less grabby and easier to control, albeit a bit slower.
As I stated in another post, I feel that the banjo plays a major role in the performance of this tool. I'll tell you right now that the Nova banjo is just barely adequate with regards to the forces exerted by this coring tool. With the force on the tip, the leverage applied to the banjo is very great. It actually will twist/bend the cam causing the tip to drop, which changes the angle of attack, and you get a "grab". It still works, but you have to go slowly.
On the other hand, a Oneway banjo is rock solid. So solid in fact, that I've bent the knife that I borrowed from my friend (replaced it, of course) while coring a little too enthusiastically.