McNaughton thoughts

[Richard Jones]

some thoughts since I got my McNaughton. The other info that I've seen on the web has contained more math in it than I care to use or learn.

When I'm coring bowls with the McN, I've been trying to "track" where my tool post is in relation to the piece to try and get some sort of "standard" data points. The distance between the base and the piece doesn't change that much, so I'm trying to develop a means of measuring where the toolpost is in relation to the interior diameter of the core, and depending upon thickness of blank, diameter of blank, and which knife I use. I almost always wind up using the middle sized knife in my set (standard).

Of course, I'm trying to do all this AND not take an hour doing it each time. Currently I'm using a framing square to "extend" the interior diameter line higher, and eyeballing the knife over both it and the McN gate. Works pretty well so far, haven't made any religious artifacts (hol-e-y bowls) in some time now. That's when I call the tool the McNaughty, amongst other things................

Any thoughts?

Rich

 

[dbonertz]

If it works for you and is fast and efficient and you're comfortable then use your system for sighting your angle of entry. The following is my long winded method of sighting the tool if anyone cares to learn a fast and easy way to sight the tool for coring. Note, there is some mundane information but all the information is needed to become successful at sighting this tool.

I production rough turn bowl blanks and had to develop a fast and easy approach sighting the tool for angle of entry, correct tool for bowl curve and bowl depth. I face of the bowl blank and cut a quick V for how many cores I intend to take from the block. I eyeball this but when I teach someone how to use the tool I show them how to layout the face using the 10% guide and then have them cut the V's. I will then use my pencil and mark on the outside of the blank where the inside bottom will be on all of the cores that I am going to take from the blank. These lines need to made in line with the spindle along the top of the blank (this step is easier, when learning, if you have a spindle lock). Again, I eyeball these but teach how to measure and lay them out for those interested. Now you have two points of reference done in about 30 seconds one set on the face and the other on the outer edge.

To determine the right blade to use hold one up to the outside curve of the bowl blank (this is a quick way of doing it but once you get more experienced you will most likely skip this step also). The curve of the blade should resemble the outside curve of the blank pretty close. For bowls smaller than 7 or 8 inches you may choose to use the smallest curved blade rather than one that matches the outside curve to give you more of a rounded bowl shape do to that first core is generally not very deep.

Now for sighting the angle of entry. First use a gouge and cut the inside of the smallest bowl your going to take to the depth of the line you made on the outside of the blank (I just measure from the face of the blank to that line and then the depth of my bowl cut in relation to the face) and to the wall thickness you have chosen for drying. Line the bottom point of the < tip to the next line on the outside of the blank, which should be the inside bottom of the second bowl, and the blade tip in line with the lathe shaft (I use a small wood step stool for the sighting operation so I can see everything from a straight top down view). Now grab the cutting tip with you left hands index finger and thumb from the top of the blade and across the points of the < of the cutting edge. With right hand in a underhand grip hold the tool handle where the tang goes into the handle. Line the tool shaft with the V groove you made on the face of the blank where you will start your cut for that bowl (once you get used to this concept you will be able to determine from this point whether you have the right tool - for bowl curve and for bowl depth). Now in a fluent motion replicate the cut of the bowl blank and stop at the face when the front edge of your left hand finger holding the cutting edge meets the face of the blank and look straight along the tool handle and see where it is pointing. That is your angle of entry. Now put your tool in the turret and put the tool tip < in the V on the face and and stand back and look along your tool handle and line it up to the spot you have determined. Start your lathe and cut your blank - repeat the sighting for the for the next bowl. Note you can use the remaining block as a jamb chuck to cut your tenon on the core if you choose.

I know this sounds confusing so let me clear some things up. Once you grab this concept and are eyeballing rather than measuring you will go from facing the blank, cutting the V's, marking the outside and sighting your angle of entry and be cutting in less than a minute. One important detail when replicating the cut is do not rotate the tool tip all the way out to the face of the blank. You must stop at the width of your finger from the face or you will cut to deep into the larger blank. The only reason that I can think of why this is is because you are lining the tip to the lathe shaft center line for replicating the cut. But when you cut you will stop short of the lathe shaft center line by about your finger tip width and pop the blank out with the heel of your hand.

In conclusion, this tool is a lot of fun but has a lot of nuances to it (in other words learning curve). I hope this helps you and anyone else struggling with the angle of entry.

 

[John Giem]

The method of using the McN system as described above was demonstrated at the last meeting of the Rocky Mountian Woodturners (RMWT) by Dale Bonertz here in N Colorado. I have also had some coaching from Dale. I write up all of the demos presented to the RMWT and publish them in the Newsletter the following month. I will be writing up Dale's demo, with photos, for the February 2012 RMWT Newsletter. It will be distributed on February 2, 2012, and will be posted on our website shortly afterwards, www.rmwt.org. Anyone interested can go there and read the writeup.
Feedback is welcome.

 

[John Giem]

Update write-up

I have completed the write-up for the demo presented by Dale Bonertz on the McNaughton Bowl Saver System. It will be in the February 2012 Newsletter for the Rocky Moutain Woodturners. I expect it to be on our web site, www.rmwt.org, by sometime Friday. I hope that it helps you. Dale has an easy straight forward method of using the system. It is completely explained in the write-up.

John Giem

 

[Bob Svoboda]

Thanks to Dale and John. Just the sort of information I have been looking for.

 

[Thomas Stegall]

Don't know if you are interested, but there is no an accessory laser system that can be bought that is specifically designed for the McN.

http://www.woodturnerscatalog.com/s...ter_Saver_Laser_Guide___ctr_saver_laser?Args=

 

[robo hippy]

The laser does help. The photo shows it mounted improperly. It was designed to mount with the vertical post mounted to the side of the handle rather than directly over the top of the handle. Kel's idea was that you could raise and lower the post according to the size of bowl you were coring. It also mounts on the handle with the same (though longer) set screws that secure the blade. Well, I chopped the post off to proper height, and welded the bracket to the handle, with the vertical post directly over the handle. Works a lot better. Randy Privett of Monster tools also makes a laser pointer that adapts to the McNaughton handle. I have found it lets you know if you are off course and need to correct. Like one turner mentioned to me, "Seems like I am always 1 inch too deep, or one inch too shallow."

For aiming, I hold the blade up to the outside of the bowl. If the blade curve is flatter than the curve of the bowl, I need to aim more in towards the center. If the blade is more curved than the bowl, I aim more parallel to the sides of the bowl. I set the gate in place, and then hold the blade over the top of the bowl and gate to see where I want it to go when inside the bowl. Then I core.

Any one who has used it swears at it. Any one who knows how to use it swears by it.

robo hippy

 

[dbonertz]

Trying to put into words the method to site the tool I found difficult. Between John and I working on it we hope it makes sense. There are pictures to go with the write up so we hope that helps. To become proficient with the McNaughton tool one must learn some concepts and understand why. Some of the information may be mundane to the experience user but their is information for everyone. Once you learn the concepts it is a very fast method to set, site and start coring. Also, once the concepts are understood there a several shortcuts that will make it even faster.

What Robo describes for siting the tool is actually a better method to find the right cutting bar to use. I don't recommend using a cutting bar that touches in the middle between the cutting tip and the tool handle shaft unless it is very close to the exact curvature of the blank. As Robo said you have to aim shallower or it is likely you will make a funnel out of the bigger blank. You will also end up with a thicker wall about 1/4 to 3/4 way down the inside of the larger bowl blank that will need to be thinned with a gouge for drying. It is better to use a cutting bar that has a small gap (less than 1/2" if you can) between the cutting tip and the tool handle shaft.

I do hope you enjoy the article and please help me understand what you would like to have read in the article if we missed something. These are good opportunities for everyone or me to learn how to write comprehensive articles. Besides I have broad shoulders.

Dale

 

[John Giem]

I second Dale's comments about feedback. I tried to include the info I wanted to enable me to use the tool even though it got a little long. I think that I left out a few fine points like adjusting the set screw in the turret. Comnments are welcome.
John

 

[Richard Jones]

....................What Robo describes for siting the tool is actually a better method to find the right cutting bar to use.

Dale,

Better than what?

I do agree that this is a difficult subject to explain in writing. So many simultaneous dynamics.........Makes my head swim........

Thanks, look forward to the demo info.

Rich

 

[dbonertz]

Richard,

Robo said he holds the tool against the blank for siting it to core. I am suggesting that is a better method for making sure you are using the correct tool for that blank. Hold the curve against the blank and see how the curve matches the roundness of the blank. If it is close to the same then it is the tool to use. It is better to do this than just grab what you think may work and and not check it against the blank and just start coring - makes funnels that way.

Robo has experience with the tool so he can imagine or maybe a better word is envision the cutting radius when he starts his cut. That works well for those who have quite a bit of experience with the tool but not so well with beginner and intermediate users. I am hoping that what I have come up with will get you started off on the right foot and take some of the mystery out the McNaughton coring system.

John did a good job of writing the article for our news letter. He sent it to me to proof and that is when I discovered putting a how to into words is difficult. I have a new appreciation for those who write books and this was a simple article. The feed back would be great.

Dale

 

[robo hippy]

I probably use the medium curved blade for 90% of the cores I take. It seems to fit the common bowl shapes I make. I have thought for years, that there needs to be one more blade for the set inbetween the medium curve, and the small curve. It is a pretty big jump.

robo hippy

 

[rsser]

Have you told Kel?

 

[robo hippy]

Several times. Hopefully he will be in San Jose, and I can talk to him again. I really need to sit down with him for a while. Maybe I need to talk to Mike Mahoney first.

robo hippy

 

[rsser]

Hmm. He would've sold another set of hollowers if he'd replied to an email about whether they'd fit a particular rig.

I've just acquired a Mark 1 corer 2nd hand and have been reading all your posts. Lots of good info, thanks.

Wondering about the worth of replacing the tool gate with the newer M8. I gather it won't fit the old large blades but will handle the rest.

 

[John Giem]

There seems to be some confusion on selecting which curved cutter bar to use to core out the bowl. Stepping back and looking at what we have and what we know, we can select the 'correct' cutter without a lot of guess work. 1. We know that the curviture of the cutting bar sets the curviture of the outside surface of the bowl. 2. Using Dale's process, we mark the face of the blank with starting vees between each bowl. 3. On the top of the blank, we mark the intended position of the bottom of each bowl. For each bowl, these mark two points for the cuvered outer surface.4. Dale has us get on a stool and look straight down on the bowl and cutter and then swing the cutter around to find an aiming point. OK, while we have the cutter bar over the blank with the tip at the intended bottom of the bowl and the shaft over the starting Vee, the curved bar that we are looking down upon represents the shape of the bowl that will be released. So, to select the correct cutter, place it over the blank with the tip at the center line at the intended bottom of the bowl. then when the curved shaft is placed over the starting Vee, the curved bar shows you what the profile of the bowl will be. If you don't like the shape, select another until you get the shape you want. This practically eliminates any guess work on selecting the proper tool. Instead we are using the bowl blank itself to show us which cutting bar will yield the dessired curvature for the exterior of the smaller bowl and the interior curviture of the of the larger bowl.

 

[Richard Jones]

I have downloaded the newsletter and will be studying it over the next few days whilst in the "library". Dale, I know this is difficult to explain, my thanks to you for your hard work. We already have a curved object, i.e., bowl, and then we introduce another curved object, i.e., blade, and then we attempt to control the outcome of where the outcome will be and hope and pray the blade doesn't outcome the bottom! 3-D movies got nothing on this!!

I already use the "stool" method and the framing square just extends the line of the cut vertically to the blade while sighting down. So I guess I've already been using this method for a while.

My attempts to calculate repeatable distances are running into way too many variables, i.e., depth of bowl, diameter of bowl, shape of bowl, etc. As I said before, makes my head swim. Eyeballing (not Reckless Eyeballing, that's a whole 'nother subject) is far quicker than measuring stuff, at least for me.

Good stuff, guys, thanks.

Dale, will get you some feedback soon. Thanks again.

Rich

 

[dbonertz]

Thanks Richard

 

[robo hippy]

Eer,
I actually prefer my two older McNaughton tool rests. The newer Mark 8 just has too many things on it. All of the extra gates just get in the way. Most of the time I use my 2 gated old rest. I do like the square tube section for running the blade through better than the older T rest. Having the through bolt to use under the blade is a nice feature for beginners to keep the handle up against the top of the support. I learned without, and find no use for it.

Blade selection isn't much of a problem really. I use the medium curved blade for almost all of my cores. The small curve is tighter than I use most of the time.

robo hippy

 

[John Giem]

For those of you following these threads on bowl savers, there will be an article on 'Bowl Saver Systems' in the February 2013 issue of the American Woodturner. I think that I have addressed a lot of the above problems, frustrations and concerns. If I missed something, like your favorite gripe, let me know.

John Giem

 

[robo hippy]

Looking forward to seeing it. I did a demo when the AAW was in Portland, 2009 I think, as a tool review of the 3 coring systems.

robo hippy