Turning Archive 2005

Subject:
More on McNaughton Coring Questions.

Barry Irby
>I jumped in on someone else's thread and posted a question on Coring with the McNaughton system. I want to thank those who answered, particularly Gary and Joe. It's gotten so far down that I wanted to bring it back to the top.

I just went out and laid out my cutters on circles I drew. I have one that "fits" a 7" circle, 11" and a 16". I say "fits" because it's certainly not exact.

Most of the 7" one fits on a fairly smooth radius but the tip with the cutter turns out about 3/16" and so does the curve at the handle end. That is, the first and last inch "flair" outward.

The 11" one follows the curve, but has a bump or bulge in it so that it touches on the inside at one point, but between that and the tip, the curve is about a 1/16" hing and then it flairs toward the handle.

On the larger one, the knife follows the 16" radius for about 2/3 of it's length and then flairs out about an inch.

It seems to me you guys are right. The arc of these knives must be a segment of a circle. The knife must be bent in such a way that the blade will follow the tip and that the blade must lie in the path cut by the tip. If the tip is 3/8" wide and the blade of the knife is about a 1/4" then I shod be able to draw an inner circle and an outer circle 3/8 inch apart and the knife should lie between them. Otherwise, the cutter or tip is not clearing a path for the shaft and it must bind.

Did I get that right?

Wonder if I some how bent these knives or did they come the way they are? I would like to look at a new set to see if they are like mine. Has anyone ever compared two or three sets to see how accurately they are bent from the factory?

Why is it important the tip align with the handle. So you know where it is or does it have to do with the cutting?

Should I try to bend mine as Gary did or should I contact McNaughton? I doubt I can bend the tip of my smaller one in tighter. I would have to straighten the curve to make the tip lie in the path. Might end up as an eight inch radius.

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