McNaughton Coring System Issues

[Dick Strauss]

I tried to contact KM about the issues with my coring system. Kel responded by saying that he didn't have any record of my emails to him from a few years ago (no great surprise). After being somwhat insulting in his opening, he suggested the system should work right based on the basic dimensions I provided to him. He was not willing to work with me based on the basic data provided.

I politely responded that I was still hopeful given the specific dimensions provided below. I also provided some additional information that I thought he might find informative. He has yet to respond over the last 3+ weeks so I assume it is a dead issue.

I'm posting the dimensions of my set here so that others aren't stuck in the same boat with knives that are hard to control without modification. I'd suggest you measure your system right away upon receipt if possible. Regardless of what the manufacturers spec is, I would immediately ask for replacement knives/blades for any gaps bigger than 0.010" on the standard set. It may not be your technique that needs fixing but rather the tools themselves!

Knife Dimensions and Capture Gaps
The thickness of the standard knives vary along their lengths from tip to handle as follows:

smallest radius...0.220, 0.221, 0.223"
middle radius..... 0.234, 0.231, 0.234"
large radius....... 0.228, 0.228, 0.227"
straight blade.... 0.231, 0.233, 0.229"

Turret post gap width (standard opening)... 0.241"

As you can see, there is not much consistency to the thicknesses of the knives. Hopefully this has improved over time. One knife has as little as 0.007" in the standard gap while the other has at max a 0.021" gap. The 0.007" gap feels quite secure while the 0.021" feels very sloppy. This 0.021" gap allows for the knife to rock a few degrees in each direction while"captured".

You can simulate this with a 1x4 board with 1/4" rounded corners (just like the coring knives). Place the board in a vise with an opening that is 1.1" wide (or roughly 10% wider than the thickness). You can tilt the board a few degrees to one side or the other. This blade tilt translates into one side or the other of the scraper tip hitting the wood first and will make it very difficult to core smoothly while not getting catches.

My solution is to use a piece of thin metal and wrap it around the turret post when coring with certain knives. Don't put yourself in my position... return anything in question before it is too late.

Take care,
Dick

[Leo Van Der Loo]

Maybe you should have gone this way ;-))

http://www.youtube.com/watch?v=zSQ8H8IjOWo&NR=1

[Jeff Nicol]

I think you are being to precise on what you expect from the McNaughton system. It really does not matter if the bars are so precise, as long as the cutter cuts larger than the blades I see no problem. I have found that the blades being free to move wherever I needed them to go is better than to tight. I even took some material off one of mine as it was too tight and got bogged down with sawdust and chips. The McNaughton system is not a put it on the lathe and core a bowl system like the OneWay and the Bowl saver. You get a lot more freedom to do a lot of different types of coring than the others. There is a learning curve and for some it is not easy, and some give up and sell the set. I love mine and it works just as I hoped it would.

So remember they are not precision machine made and will have some variance in thickness, and a few thousanths should not cause any trouble. I think it is tool placement and operator patience and practice that makes the tool work well. Reed Gray has a video and so does Mike Mahoney on the system, I reccomend watching them and then make your final decision on the McNaughton system.

Not trying to ruffle your feathers,

Jeff

[Mark Levitski]

I agree w/ Jeff, and also not trying to be antagonistic. The thousandths and even hundreths of an inch are not what is giving you problems. It is the learning curve which accompanies each and every turning tool. Remember figuring out what riding the bevel was? Some things come easier than others for people. I read about all the problems with free-hand hollowing and it scared me away a little. Found out it had about the same learning curve as my gouge work and then my McNaughton coring work. Now I routinely put on the Kelton toolrest and get coring with little anguish. I also hollow without a captured system, and lo and behold, it CAN be done and without stress.

You might try backing off the toolrest from the piece enough so that the taller portion of the knife is "captured" as this helps in the knife not rocking as much. I also keep it twisted a bit one way in the gate to begin with to take out any play. I had read that one must position the rest very close to the piece, and this is not the best thing.

Anyway, good luck, Dick. And ease off and relax about it. You will grow to use it well and even like it. If you see through this, it will help you approach all other things with lathe tools.

Mark

[Kyle Iwamoto]

Ditto what Jeff and Mark said. I recently got a coring system and IMO the sloppiness allows me to wiggle the cutters, and open up the kerf a bit. Opening up the kerf seems to allow the chips to fall out way easier than if the kerf was tight... Of course, YMMV. Oh especially ditto that I'm not trying to ruffle any feathers. There is a learning curve. I have still yet to get more than 1 core..... Well, thats not really true, I got 2 bowls and a funnel once.:)

[Nathan Hawkes]

Echo of the other posters so far. Also, if you look in most industrial supply catalogs, there is a fair amount of potential variance in steel bar stock. Usually there is at least a plus or minus 0.002" variance--this means a range of 0.004" that the material can acceptably fall within. Also, there is a very steep learning curve to the McNaughton. I've cored a few hundred bowls on it, and I still make funnels occasionally. I've even learned to tweak the curve of the knives with a pipe wrench and a bench vise. 1/4" steel is actually quite bendable. A very severe catch can end up with a slight twisting of the knife that can be easily repaired. Even though the learning curve is steep, and catches can bend the tool, there is no other commercially sold system that comes even close to the versatility of the McNaughton coring system.

Edit: one thing I meant to mention is that the gap between the posts is supposed to be a fair amount wider than the thickness of the bar, otherwise it would not advance through the cut the way it does. You can turn the turret post and/or knife to get the right amount of support from the gate posts.

[Leo Van Der Loo]

I hear the versatile argument a lot, but I would say that any curved blade will cut a curve.

And I don't see a position where you could place a curved knife with the Mc Naugton that you could not with the Oneway.

Yes you can take a couple of cuts to widen the kerf so you can make a different curve, but I think you could do that with a Oneway also, but why do that, could you not turn that shape on the blank when cored, easier and probably faster also.

I bet you could even make a funnel if you tried with the Oneway, but you could tell that before you start, it would not be an oopsy ;).

There's one thing you don't need, with the Oneway system, DVDs or special instructions to maybe get passable results.

Yes I know you get what you pay for, but guaranteed results would pay that back pretty fast I would think and so do others :D

154690

[Jeff Nicol]

All I would suggest is for you to check your own gaps/blades. Possibly this issue has been solved with the newer sets you own????

The Mahoney video and Steven Russell (?) videso wer watched ad nauseum but I was still having all kinds of problems with coring using the tight radius blade. I finally tried the virgin middle curve and had absolutely no issues (hmmm??). I tried the virgin slightest curve knife and had issues again (hmmmm??). So, I have issues with the slightest and sharpest curved knives in wood from the same tree section. Any guess which ones have thinner knives and thus have a larger gap and allow for more rotation????

As others have said, the Oneway system works the first time you take it out of the box. I was able to get 4 cores from an 11" blank on the first try (no connection to OW)!

Soapbox has now been smashed!
Mine is older than yours so that is not the issue, If you want to be grumpy and not take our words as words of encouragement so be it, we are all here to try and help. Patience is a great teacher, but once it is lost it is hard to regain.

Take your time that is all it takes,

Jeff

[Jeff Nicol]

This is for Leo, who we all know is a Oneway junkie, it seems no matter what there is out there for him it is Oneway or the highway. The oneway is twice the money and is pretty boring in th coring world, just the same shape bowl, one after the other just a little smaller than the last. If all I wanted was to make the same old salad bowls all day long the Oneway would be great, but for most I think being able to do many different styles makes more sense.

For those who give up easily then take the Oneway out, for those who want the challenge and ability to test your skills and ideas the McNaughton is the way to go.

Money don't grow on trees in Wisconsin, does it in Canada?
Give the other stuff a chance, please Leo,


Jeff

[Leo Van Der Loo]

This is for Leo, who we all know is a Oneway junkie, it seems no matter what there is out there for him it is Oneway or the highway. The oneway is twice the money and is pretty boring in th coring world, just the same shape bowl, one after the other just a little smaller than the last. If all I wanted was to make the same old salad bowls all day long the Oneway would be great, but for most I think being able to do many different styles makes more sense.

For those who give up easily then take the Oneway out, for those who want the challenge and ability to test your skills and ideas the McNaughton is the way to go.

Money don't grow on trees in Wisconsin, does it in Canada?
Give the other stuff a chance, please Leo,


Jeff

Not a Oneway junky Jeff,, and calling someone names isn't my way, little kids do that.
Just as I say, we know the Oneway system works right out of the box, it can do what the other systems do and better without the needs of daylong lessons or DVDs to be able to use it, and that is all I am referring to, it just is a better system, and yes it does cost a few $$ more that will be paid back with the extra bowls you are able to make with it, without frustration and making expensive funnels.
You can take issue with that if you like, but that's the way I see it.

And that is the end of this story.

Have fun and take care
Leo Van Der Loo

[David DeCristoforo]

"...we all know is a Oneway junkie..."
"...calling someone names...little kids do that..."

Ooo... ooo... Fight!!! Alright boys... choose your weapons. Gouges at ten paces?

[Nigel Tracy]

Tee hee funny stuff... "gauges at ten paces"... :)

I've used the two systems and I'd say that Leo and Jeff are both right. Vibration is slightly more possible with the KM, but then there's the upshot of slightly more versatility. Ya ya the oneway can basically achieve the same forms, but not with some contorting of the setup, i.e. using the large knife on a small, narrow form in order to get a vase out of it.

They're different, but they both work just fine when used properly, i.e. with the right lathe and operator.

My .02

[Mark Levitski]

Never tried a Oneway coring system. Never tried a Kobra captured hollowing rig either, but I know that I can hollow free-hand and I am glad I have developed the skills for it (which aren't that difficult to master). Can you imagine David Ellsworth advocating a captured rig? I do turn production and welcome any technical advances to help with creating more efficiently the pieces that I make. Come on, coring is just a parting operation, isn't it? Or you can also look at it as a specific hogging out of a bowl by taking a solid chunk out of the middle instead of shaving it out. A bennie is that you can turn another bowl out of the chunk and you can't from the curly shavings. Stick the parting tool in the wood and cut it out! It is not freaking airplane part machinist tolerances, nor is it very difficult. Poor Kel must be shaking his head or rolling his eyes!

[Reed Gray]

There are cuts that you can do with the McNaughton that you can not do with a Oneway. Mostly because some of the McNaughton blades have a flatter curve that the Oneway blades, and these flatter blades are far superior in coring deeper vessels, and flatter vessels/plates. Other than that, now that I know how to use the McNaughton, it is a lot faster to set up and use. No, 99.99999% of the people who get the McNaughton can't take it straight out of the box and use it.

robo hippy

[scott schmidt grasshopper]

as a student of reed ( robohippy) I see him core stuff and looks effortless. I bought a Mcnaughty and had some issues right out of the box. had to sand and polish the blades to get them to "slide" thru the posts. also I still have an issue with the post head becoming loose if I have a small catch. I bought part of the oneway system and thats what I had learned on from reeds shop I prefer the one way for bowls I have got to get the inside out of unless its a strange form that I am coring out of then I try the Mcnaughty.
some of the things to check when you get your mcnaughton.
1 smoothness of the blades will they slide under tension?
2 curvature of the blades, sometimes they don't have uniform curves and will bind in the cut.
3 fit and movement of the tool post
4th if you bought the laser guide arm is it the right length . mine was just barely long enough to reach the blade tip with the lazer
several people have welded the lazer arm attachment ( where it bolts to the handle) so that you dont need to detach it each time you change blades
good luck and hey ,,, no name calling you boys this is a nice place to be,, lets keep it nice.. god bless, scott