Coring with McKnaughton

[Brodie Brickey]

I got a hold of a nice green log on Sunday and cut it up with the chainsaw. Once I'd rounded her off, I started coring it with the McKnaugton tool. I've had mixed luck coring in the past, shearing off the foot on a couple bowls that were smaller than these but not as green.

This time everything went fine until I was coring out the middle bowl. The shavings cleared out fine, but the tool didn't want to reach all the way to the middle. I've got the standard set and the outside diameter of the outer bowl was only 14.5" x 7.25". I finally managed to get it parted out but was left with about 1.5" stub at the center where the tool didn't break through.

My concern is that I've reached the end length of the tool so quickly. I cored another bowl last night that was the same diameter, but not as deep and didn't have quite as much difficulty. I'm using the most curved of the standard set. Do I need to shift to the shallower curve?

Of those that have this tool, what am I missing? Do I need to get the large set as well? I'm not sure that I'll be coring up to the 20" swing on my 3520. I do generally subscribe to the Tim Taylor methodology, but holding a 14x7 bowl, you get the feeling that you have to have a really big family to hold that much pasta or popcorn. I'm already having problems reaching the bottom of the bowl to clean it up (new curved tool rest on order:D).

Any help would be appreciated.

[Dario Octaviano]

I haven't used mine (not here yet) but watched Mike Mahoney's video on it. If you can, I highly recommend watching that video.

The bigger the diameter and/or the deeper (on thick blanks) you go...you need to use the lesser curved blades.

At any rate, I think you did great. Those look awesome!

[Mike Vickery]

this link goes over recomended sets for different diameter bowls.
http://www.woodturnerscatalog.com/cgi-bin/shopper?preadd=action&key=095-5000

I usually use the medium curve blade the most when using the system but I have only cored 6 or 7 bowls.

[Reed Gray]

Using the small curved blade on a 14 inch bowl won't work too well, it is suited to smaller and deeper bowls. I do wish that McNaughton made some longer blades with more curve. The medium blade is a bit too flat for me, but it is what they have. The large set has the same curves, but not the tighter curve. I really like the mini set for the last blank or two.
They also have a laser set up for this system. I don't really like the way that it mounts, but it really helps you to know when you are getting near the bottom (no more lampshades/funnels). After removing a thousand or 2 cores, I tend to aim shallow, just to be safe. Many more bad words have been said for going through the bottom than for leaving it a bit shallow.
I have found out that I use the medium curve blade for most of my coring also, it just seems to fit, and I can core up to about 14 inch diameter blanks with it. Some times you have to break the core out. This is fine as long as the wood is fairly straight grain, and not a piece of crotch wood. I have ripped out the bottoms of 1/2 inch thick bowls because of crotch grain that is running vertical rather than horizontal. Some will pry them out, but I usually hit the edge of the core with my hand, or the handle of the coring blade. You don't try to bash it, you want a sharp quick rap. If you can wiggle the core at all, you are down to about 1 inch or so.
In reality, I think you get one core per 1 1/2 inch thickness. The kerf is about 3/8 inch wide. By the time you flatten out the bottom to make a tenon, or a recess (the way I prefer), you loose more than 1/2 inch. Add the 1/2 inch thick bottom, and you are up to 1 3/8 inches. Then add finish cuts.
robo hippy

[Brodie Brickey]

Thanks. I've got a blank left to core with. I'll see if I can get it working better with a gentler curve.

I have to say that I do love not having to pickup so many shavings.

[Dario Octaviano]

I have to say that I do love not having to pickup so many shavings.

AND...getting more bowls out of one blank!!! ;)

I am excited...my set arrived last night! :D

[Brodie Brickey]

Dario,

Congratulations! May you have many shaving minimized bowls!

I do have some problems with mine, but I also love pulling more than one bowl out of a blank.

[Dario Octaviano]

Brodie,

Question, I only have a Talon Chuck with #2 jaws...will it be sufficient to hold (and core) the size blanks you showed?

Or do I need Stronghold/Titan?

LOML insists that I get one (either Titan or Stronghold) for safety reasons and much as I love to indulge her...I already spent my tool budget for the year :(

[Gordon Seto]

Question, I only have a Talon Chuck with #2 jaws...will it be sufficient to hold (and core) the size blanks you showed?


Dario,
As per Mike Mahoney's Center Saver DVD, he recommends the jaw size to be 40% of the blank.

It is always a good excuse to get a new chuck.

Gordon