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McNaughton coring advice

J

James Smith

Joined
Jun 13, 2008
Messages
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Location
Richmond Virginia
I just purchased the McN standard system. Using the advice on this forum I was able to jump right in and make 4 bowls out of a 12 inch blank of white oak and the same number from a 13 inch Ambrosia maple burl.

My question is about the set screw on the gate. The assembly instructions stated to keep the screw loose enough to let the gate rotate. I found that when I set the blade entry point, if I tighten the set screw so the gate can not rotate the process goes much smoother and the blade path far more predictable.

Should the set screw be tightened, or could I be doing something wrong that makes the loose version less predictable.
 
James
Might I recommend asking your question in the "Main" forum. As the title of the "sticky" post just above your question states
This Subforum is for TELLING how to not for ASKING how too.
Click to expand...

TTFN
Ralph
 
Suggest you email the man himself, Kel McNaughton.

A google will return his website in New Zealand.
 
Last edited:
Do not tighten the set screw to make the gate imobile. It needs to rotate to change the blade direction so as not to go too deep. The instructions are correct.

You initially align the entry path for the curvature of the blade and maintain it for about an inch or a little more. Back the blade back out and take a little off of the outside bowl to allow for a shallower cut if necessary and to keep the cut free for ejecting shavings. This also keeps the blade running a little cooler as well. The banjo can be moved left or right and the gate will swivel to allow cutting the new path (without changing the gate height in the banjo). Tightening the set screw will wear out the mounting shaft as well over time. Just leave it loose.

You are doing quite well with 12" bowls for the number you cored. Keep up the good work.

Bill
 
Apology

Sorry guy's,
I showed my new member ignorance. Not only did I post a question in the wrong area, I'm asking a question that should involve the MFG instead of the forum. I've sent the question via the McNaughton website and would appreciate it if the moderator would remove this thread to cover the errors of my ways.
 
Thanks Bill

I must have hit the send button on my apology post seconds after you posted your reply. Thanks for the advice and encouragement. I've made a total of about 20 bowls so far and 8 of them has been with the coring system. Needless to say I wear a beginner badge, but I just couldn't bear to see the big piece of ambrosia burl wind up as shavings.

Thanks again!!
 
No problem James and fully understood. You are correct to contact the mfg site on this. Should you want to discuss your use further at anytime, just ask. Good luck.

Bill
 
Contacting the Manufacturer is a good thing, but asking on the forum is a good thing as well, because as we all know, "all of God's children are different, and some of us are more different than others."

Now, as to tightening the set screw, I am all for it, and have been doing it this way for years and several thousand bowls. The set screw will tighten down the support fingers so they don't rotate. They don't need to, but the tool support that supports the back of the blade does need to rotate. The fingers act as a flucrum point for the blade, you pivot around it as you make the cut. Having them move made it more difficult for me to aim, so I fastened it down tight, even drilling a divot in the post, and then adding a second set screw to tighten the first one in. It made aiming a lot easier. Any course corrections are easy to do, and for me, easier. As far as running cooler, the only heat that is generated is when the blade is binding in the cut. The blade always wants to drift towards the outside of the cut, never along the path that you want. So you end up with the actual kerf being flatter than the curve of the blade. This is when you come back to the top of the cut and remove a bit from the outside, or inside depending on which way you want to correct. That is determined by weather your path is too shallow or too deep. They do make a laser pointer for the system, and I have found it to be a great asset. You can easily see how your aim is going, and what you need to do to correct, rather than guessing.

Any more questions, just ask.

robo hippy
 
McNaughton response

I did send a note through the McNaughton web site last night and received a prompt reply from Kel. The quick support warmed my heart and made me a customer for life. I'll share Kel's response and (my reply for what it's worth)


Kel's response was :
Hi James,

Thanks for choosing a Kelton product. I am pleased that you were able to
successfully use it so quickly. You make an interesting point. The head is
designed to rotate to allow continuous relalignment of the support pins as
the cut is made. Maybe you have discoved something. I will have it looked
into. Appreciate you advisising me of this. One thing that I am curious
about is that you mention AAW instructions. Would you be able to advise me
as to where these are ?

Thanks and regards,

Kel.

My response to him (I put in a plug for the great advice of the forum😀)

Thanks for the quick reply.

The AAW website has a forum, and I simply did a search on "McNaughton" to find many threads with tips and discussion about using your tool. I gleaned all the experience I could from the site and your instructions before using the device. I had heard all sorts of anecdotal stories of dangerous results, and I am an extreme beginner to turning, but am comfortable around tools.

When the gate was loose, it seemed to be that the trajectory of the blade could vary with the rotation of the gate. I seemed to get more catches because the small variation in position allowed unpredictable change. With the gate tight, I was able to map out the blade path on graft paper before I begin the cut, and the resulting core had the shape and size of the grafted drawing.

I've only made 20 bowls so far and 8 of them were with your system, so I am probably just doing something wrong when the gate is loose. Needles to say I really appreciate your time and advice. I immediately began enjoying your tool and look forward to many more rewards.

Thanks again,
James
 
When you assemble the tool rest, there is a small set scew in the back of the top part that has the vertical tool guides. When you put the top part on the tool rest post, the screw is designed to tighten into a groove on the post to keep the top part on the post, but also allow it to pivot.

I just purchased mine, so maybe it is a revision from yours.

Side note,
Thank you for the information on your website about using the tool. I also have your video so I appreciate the help you have given me to pursue the passion.
 
Bill Pottorf said:
Do not tighten the set screw to make the gate imobile. It needs to rotate to change the blade direction so as not to go too deep. The instructions are correct.

You initially align the entry path for the curvature of the blade and maintain it for about an inch or a little more. Back the blade back out and take a little off of the outside bowl to allow for a shallower cut if necessary and to keep the cut free for ejecting shavings. This also keeps the blade running a little cooler as well. The banjo can be moved left or right and the gate will swivel to allow cutting the new path (without changing the gate height in the banjo). Tightening the set screw will wear out the mounting shaft as well over time. Just leave it loose.

You are doing quite well with 12" bowls for the number you cored. Keep up the good work.

Bill
Click to expand...

Aren't all these contraptions essentially a swinging parting tool? Most advice on use of a parting tool includes trimming the sides of the cut to reduce side grabbing. No reason it wouldn't apply here.

Joe
 
Joe Greiner said:
Aren't all these contraptions essentially a swinging parting tool? Most advice on use of a parting tool includes trimming the sides of the cut to reduce side grabbing. No reason it wouldn't apply here.

Joe
Click to expand...

That is absolutely correct! If you do not clean out the back of the cut, the blade can become bound in the cut. This results in a catch and a bent blade.

Bill
 
There must have also been some additional design changes in the blade design. The cutting surface on the standard parting tools creates a kerf thinner than the the body of the tool, so the body will absolutley jam in the resulting kerf if I don't make a second pass.

The cutting surface on the coring blades I received creates a kerf larger than the thickness of the blade. The tip is pointed and creates room for the blade on both sides of the cut.

As long as I made sure the cutter was on the center axis, and took my time to clean the shavings out of the kerf, the only catches I had were either due to learning how to regulate the speed I intoduced the cutter into the wood, or the movement of the gate as I progressed through the cut (why I tightened the set screw).
 
The older blades had the cutter wider than the blade, but it was flush to the inside of the blade, and wide to the outside of the blade. The new ones have the same width of cutter, only now it is centered on the blade. In theory, you should be able to make one cut without course correction all the way to the bottom of the bowl. Most of the time, I can't make one smooth cut all the way to the bottom of the bowl without any course corrections. Impossible to do on large bowls, and some times doable on medium bowls, and more common on smaller bowls. The fixed center/pivoting on center (Oneway and Woodcut) are able to do this, but when using them, I can feel that they want to drift. I think the drifting of the McNaughton is due to the blades being a bit longer, so there is some flexing of the blades as they cut. This is just the nature of the tool, and some thing that you learn to deal with.

When you are off course, and the blade is binding, you can course correct either on the inside or the outside of the cut. Either way will work. With the old style of blades, it was almost impossible to make a correction on the inside of the cut because of the cutter design. With the newer design, this is easier, especially if you have the support fingers tightened down rather than rotating. Which way you correct depends on how your aim is. If you are going too shallow, then correct to the outside of the cut. If you are aiming too deep, then correct to the inside.

Catches can happen for a bunch of reasons. Some times, they just happen. like when you have cleared the chips, and are putting the cutter back into the cut, and push a bit too fast. If you are below center, they will happen more. Some woods do tend to chatter more, and when that happens, there are more catches (mostly with harder woods). Some times they happen when I am really pushing the tool to make it cut faster. This too can make the tool catch. I had never really thought about it, but when the blade is binding, that may have contributed to some catches. Most of the time, you will see steam, and even smoke when it is binding. If you do have a catch, and/or through a lot of use, the blades will bend (rather than break, which is a design feature). The bending is a torque/twist, not a pretzel type of bend. You can fix this by putting the cutter end of the blade into a vise, and using a big pipe wrench or adjustable wrench to twist it back into shape.

If the chips are flowing, keep cutting. if they stop flowing, clear them out. I have had times when all was going well, and then a sudden plug up of shavings which would stop the lathe with a lot of squeeling.

The tool post on the tool rest has always had the groove in it, at least since I got my first one some 8 years ago.

robo hippy
 
Bill, I have seen your video where you demonstrate the Mcnaughton coring tool. You have the older style which is already set up. The newer style is built for three different styles of blades, while the older only takes two. The set screw is to hold the gate and pins on.
 
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