Pics of McNaughton Tips per Mike Cruz request

[mike ash]

Here are pics of the McNaughton system blade sharpened as Reed Gray showed me. I've watched his DVD numerous times now and learn something each time!!!
The first pic shows "squared off tip". The second pic is a side view. Hope this helps. Just like Reed says in his DVD, sharpening them like this improved the cutting efficiency and helped keep the kerf from clogging us so often.

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[Mike Cruz]

REALLY? I'm so surprised that it cuts better squared off. I mean, I've heard of people doing it, but it baffles me. Hey, I'm not saying you are wrong. I just don't get it. I haven't had a chance to go back to try some more coring, but if I have issues again, guess what I'LL be doing!

Thanks for posting the pics, Mike.

[mike ash]

Mike - The way I understand it is this way..... Take the distance across the cutting edge of the pointed version 1/4" + 1/4" = 1/2", versus the distance across the squared off version 3/8". So, the curly for each is 1/2" compared to 3/8" and the kerf width is the same in both cases. Then think about which size curly comes out of the kerf the best. Then think about which cutting edge provides the most resistance in cutting. I think it is the one with the shortest cutting surface (just like a think kerf saw blade). Make any sense?

Mike

[Reed Gray]

For me, it was just less cutting surface on the end of the tool. The spear point was Mike Mahoney's idea. It is supposed to be better if you are going to cut the core totally off. You have to do this with end grain pieces, burl, and some crotch pieces. If you don't, and try to break the core out, you will rip right through even 1/2 inch plus thick bottoms. The main problem I have found if I have to cut it all the way off is that the tip is below center by the time you get to the end, and with the cutting pressure on that long of a lever, and the flex that is designed into the system. Two solutions, one is to raise your tool rest. The other, which is not recommended, and only if you have the full length handle, and a lot of experience, and slower speeds is to drop the handle a tiny bit which raises the tip. You can feel when the cutter is too low. Mike does tend to fish tail when coring, or move the tip back and forth to open up the kerf a bit. This does have you cutting more with one side of the spear point, and then the other, but both sides do tend to engage the wood. The sides of my kerf tended to get pretty ragged, and it would clog up faster. I prefer to plunge straight in, and if I am going to open it up a bit, I come back to the top and open it up 1/16 or so. The full width shavings just plug up the hole more quickly. Kel was astounded that I ground the spear point off: "YOU DID WHAT??????" With the old style tips that had a bevel across the front, or as I called it dog eared to one side, I started experimenting after I heard that people were changing the grind on their tips. I didn't try spear point, but did use straight across, bevel/angled to the right, and bevel to the left. There was no difference in how the blades tracked through the cut, or how they cut. I just ended up with square as the easiest to do. You do grind away a fair portion of the tip, and I generally do it more gradually rather than taking it all the way down at once.

The Woodcut has a square tip, and cuts very nicely. The top of the cutter is also concave, which some one told me helps to eject the chips. I don't know for sure about that though.

I had Oneway send me one of their cutters that was not ground to their point. I tapered the sides a bit, and just put a bevel on it. I liked how it cut better than their standard one with the point. It is a bit more aggressive, and they told me that is why they don't sell it to the general public that way. Their point is supposed to be more of a chip breaker with the sides clearing/cutting out the fiber after it has been broken/cut.

Another case of this is what works for me.

robo hippy

[Mike Cruz]

Thanks again, Mike. And thank YOU, Reed. The problem I was having with my last (second actually) core was that I was getting really bad catches...and not due to chips not clearing. More likely to being below center. Anyway, I might just start squaring the tip next time I take it out and sharpen it. THANKS!

[Reed Gray]

Catches and/or grabbing seem to be a problem some times, and not others, and I have never figured out why. You do need to be at center, or slightly (1/4 inch or so on larger bowls) above center. Some woods will tend to produce a lot of chatter. I think it is for the same reason that some pieces of wood will have more tear out than others, no matter what you do.

robo hippy

[Mike Cruz]

I posted the issues I had in another thread, Reed. The short story is that I had some green very clean perfect Cherry. After a lot of analysis, I think I had the cutter at center (14" blank) at the beginning of my cut, so as I entered the cut about a couple of inches in, I was getting below center and getting catches that were not only powerful, but broke a perfectly good tenon. When I've had other turners over here and they saw the broken tenon, the response was a simple "WOW". I do appreciate your input and help with this. I don't want to give up on it. Actually, the opposite. I want it to be my go to tool when starting the inside of every large bowl...

[Reed Gray]

To get the center height, you extend the blade all the way out from the tool rest. Then pull up on the handle to simulate the cutting pressure. This puts it fairly close. If you get too high or too low, you have a vertical blade in a curved hole, and too far up or down, will put the blade in a bind with the top or bottom of the kerf, and not the sides. I do use a stop block under the tool rest for setting correct height. Some use cut off pieces of plastic pipe. I turn an end grain piece of wood for that. For a 14 inch bowl, I would want a 4 inch tenon. Also, line up the chuck jaws so that they are at 45 degrees to the end grain. If you have 2 on end grain, and 2 on side grain, you will get an uneven grip as the end grain doesn't compress very much, and the side grain can compress a lot, especially if the wood is wet. Having correct jaw size is important too. For a 4 inch tenon, I would want minimum 3 inch jaws.

Of course, as always, some pieces of wood just do that because......

robo hippy