One way coring issue

[David Bolson]

I have the Oneway coring system with he smallest and next larger size cutters and supports. I use them on my Grizzly 0766. I recently treated myself to the Hunter Korpro. I don’t remember ever having this issue with the Oneway carbide cutter, but I don’t see how it’s related to the Korpro.

When I’m coring with the smallest set (mine is marked “9”) there is no problem. When I move up (to the “11”), the support gets stuck when I move it in. The support angle is different than the cut. See the below picture.


I wasn’t comfortable proceeding without support, so I did something that made me a bit uncomfortable - I added a shim to change the angle of the support. See the below picture.


It works fine with the shim, but I shouldn’t have to do that. Is this a head slapping mistake (I hope so) or is there another problem?

David

 

[Steve Tiedman]

Hi David, I have no experience with coring cutters, but my thought, along with asking for sage user advice here, would be to contact the tool manufacturer(s) with photos and see if they can offer guidance. Maybe you have an improperly built tool they will replace.

 

[Bill Blasic]

Are you sure your tool is not bent?

 

[Gary Beasley]

This problem has been reported before. Recommend contacting Oneway, they may send you a replacement.

 

[robo hippy]

Well, the top outside of the blade is rubbing, and the lower inside part is rubbing. This would suggest to me that you are not spot on the center of the lathe for your pivot point. If you are slightly off center, then not much of a problem. If you are considerably off center, then it might be a bigger problem, and I have heard some say that you need to open up the kerf a bit.

robo hippy

 

[Michael Beswick]

Surely for this to work, everything has to be "square" to each other. As robo hippy points out the blade is not, so either it, or the bits that it is attached to is out of alignment. That you have to shim it confirms this. If everything else is square, then the position of the cutter in relation to the centre is off.

 

[David Bolson]

Well, the top outside of the blade is rubbing, and the lower inside part is rubbing. This would suggest to me that you are not spot on the center of the lathe for your pivot point. If you are slightly off center, then not much of a problem. If you are considerably off center, then it might be a bigger problem, and I have heard some say that you need to open up the kerf a bit.

robo hippy

Ahh. That may be it. The blank that I'm working on is just short of 22" in diameter and only about 5.5" thick. So I did move the pivot point off center to cut wider (and less deep). My mind is balking at trying to figure out why this would happen since the cutter is still making the same semi-circular cut that would make if it was centered (wouldn't it?).

Anyway, I'll check this out on a more conventional blank. Thanks!

David

 

[Dean Center]

What Reed is pointing out could happen if the cutter is higher that it's supposed to be. Has something gotten under the bottom of the cutter post? Has the height adjuster gotten turned so it sits higher in the base?

 

[Karl Loeblein]

A slightly wider cutter when coring really large bowls off center would create better clearance and reduce the need to make multiple passes to widen the kerf. Since a wider Korpro cutter isn’t an option then I’d go with Robo’s suggestion of widening the kerf over the shim.

I‘ve been thinking about using CAD program to design a tip holders to test different size triangular shaped cutters like the ones below, but first I need to make friends with a woodturner who owns a CNC machine because many one-off CNC runs can get costly.

 

[John Hicks]

Oneway made a bunch of number 2 cutter supports that were miss machined. I had one, and it did the same thing. Binded in the kerf. They sent me a replacement.

 

[David Bolson]

What Reed is pointing out could happen if the cutter is higher that it's supposed to be. Has something gotten under the bottom of the cutter post? Has the height adjuster gotten turned so it sits higher in the base?

Thanks for the clarification. That would make more sense that the angle would be affected if the cutter was too high, as opposed to being too wide. But my cutter height was pretty close to the exact center. So that’s not it.

Oneway made a bunch of number 2 cutter supports that were miss machined. I had one, and it did the same thing. Binded in the kerf. They sent me a replacement.

Hmm. I’ll send Oneway my pictures and see what they say. Thanks.

 

[robo hippy]

The blade and support finger/arm are designed for a specific radius. Given the dimensions of the piece you were coring, you need to open up the kerf. The one down side to the Oneway coring system is that the entire set up is very tall. Not much of a problem to just bump it to one side or the other. I would probably move it to the inside. Even with the McNaughton, on deeper cores, you have to open up the kerf. Not because of the height of the blade set up, but because the tips don't follow a perfect arc of the radius, and this makes them drift to the outside of the cut.

robo hippy

 

[Steve Chaplin]

I just went through this with my #4 knife support. It would bind unless lifted up about 1/2" which won't work of course for coring. Oneway sent me a replacement.

 

[Rusty Nesmith]

Hold the support up to the cutter and see if the bends match.