I have all 3 coring systems, and I demonstrated them up in Portland at the AAW Symposium. I prefer the McNaughton. For me it is the fastest to core with, easiest to set up, and most versatile.
There is no restriction on bowl design with the coring systems. The only thing that changes is what shape of core you take out of the first bowl you turn. The Oneway and Woodcut are set to standard radius cuts. The McNaughton has some regular curved, and flatter curved blades so you can get cores out of shallow plates/bowls, regular shaped bowls, and deeper vessels. With the straight parting blade, you can take a cylinder and part off plate blanks. You can not do this with the other systems. You can move the center pivoting point a bit, but this does little to change the shape of the core. With the Oneway, if you move it very far from the center, the blade and support finger actually get in the way.
The Oneway is a nice system, and is the most stable with the bigger blades. The support finger under the cutting blade prevents chatter on the biggest blades. If you have ever seen just how far you can reach any tool out over the tool rest, you know about this chatter. The down side for me, as a production turner is that on a big bowl, you have to turn the lathe off up to 4 or 5 times to advance the support finger, the price you pay for the stability. I do not really like the cutter on the Oneway. The tip is a chip breaker, and the sides cut away the broken fibers. It works fine, but is a pain to sharpen. You have to remove the cutter from the blade, and hold it up to the grinder. They have a jig for doing this which makes it easier. You have to sharpen the top side of the cutter, not the face of it. Another extra step. If I was to use this system, I would want a surface grinder of some sort, like a metal abrasive disc on a wheel of some sort. Just sharpening it on a diamond hone doesn't do the trick. I did have Oneway send me a cutter that wasn't ground with the point on it, and I can just sharpen the face of it. I like the way it cuts, and I don't have to take it off the blade to sharpen it, but it is considerably more agressive when it cuts, which is one reason why it doesn't come that way for the general public. I have had excellent responce from Oneway on any questions I have had with their system. I would control depth of cut by making a plywood template to space the system a set distance from the headstock. Pretty simple.
The Woodcut is an excellent small coring system. The emphasis is on small. The big blade is a 5 inch radius. The stellite tips are easy to sharpen, and cut really well. I have had good results with it on 1`hp lathes. The down side to me is the small size, and that you need to hook the tailstock up to the plate it on to core safely. I never have the tailstock on when I turn bowls, or core. It is a minor chore to change blades, you loosen up 2 bolts, and then switch the 2 blades. There is some chatter with it, expecially on harder woods, and when using the larger blade. They also have a laser pointer, but you can also do the plywood templates like you do with the Oneway.
Then there is the McNaughton. This is the most difficult coring system to learn to use, but also the most versatile, and for me, the fastest, once I learned to use it. This is not a tool that you can pick up and just start to use it effectivly. There is a learning curve. If you are getting nasty catches, and stalling the lathe, and getting the blades stuck in a core, and having to force the tool,you are doing some thing wrong. The only time you need to apply pressure is if you want to cut faster, and push harder to make this happen. The hard part is on figuring out what is going wrong, and correcting it. Yes, I have made all of those mistakes, more than once, and have learned to deal with it. Mostly, the blade wants to drift off course (towards the outside) when coring. The blades with the McNaughton are a bit longer, and more flexable than the ones on the other systems, and I think this is why it wants to drift more than the others. Some times you have to open up the kerf a bit. Also, since the system is free handed, you have to do the aiming. McNaughton also has a laser pointer system for the coring system, and I love it. I still have to aim, but the laser lets me know if I am off course and need to correct. No more lamp shades. I cored a set of apple bowls last week. Total time on a green turned to finish set of 4 bowls, the biggest one 13 by 6 inches was about 40 minutes. I could not do this that fast with the other systems. If you get this system, it is best if you can have some one show you how to use it, or get one of the DVDs. One is by Mike Mahoney, and the other is by me. PM me if you want more info. The McNaughton is not for every one, but I think it is the best system out there.
McNaughton now has a micro system out. I just got mine and took 2 cores on it with the apple wood, on a Jet mini 1220 vs. No problem at all, but I need to do several cores before I do a post on it.
robo hippy