Mcnaughton Center saver users

Discussion in 'Woodturning Discussion Forum' started by chrisdaniels, May 2, 2016.

  1. chrisdaniels

    chrisdaniels

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    Here I go again trying to pick your brains. I have tried a couple dozen cores now with my mcnaughton, I only have 1 lampshade thankfully but I'm not getting the angles right. my cores are coming out uneven and almost always thinner at the bottom 1/4 of the bowl with some getting so thin that I know they are going to crack during drying. I have the standard set, and the small set now and i'm trying to get proficient before I start jumping into the nicer wood and the burls that are piling up. I have mike mahoney's dvd which is fun to watch but didn't teach me much as far as the aiming and visualization process goes. He says you have to have some imagination to visualize where the cut will be but like Dale Bonnert says, you're new you don't have the imagination which is my issue.

    I have watched dale bonnert's video a dozen or more times and I like his process but for the life of me I can't get it aimed right even then.
    I have also watched robo hippy's video a handful of times for tips and have picked up on some good cues there.

    Does anybody have any good tips on getting the cut laid out and setting up the angle of entry? I don't know that it could be explained any more than Dale Bonnert does but maybe someone has some tips or tricks that I can't find.

    I don't want to spend another hundred dollars on the laser guide since i've allready dropped almost 700$ on this set up as it is so I want to exhaust every other option first.

    I have a large supply of 22" diameter hard maple logs that I want to make a lot of bowls out of but when I try to core them I get a fight like i'm battling vikings everytime I try. Thanks in advance for the info!

    Chris
     
  2. hockenbery

    hockenbery AAW Advisor Staff Member

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    Chris,
    Always try to keep the big bowl

    Start out coring them an extra inch thick for the wall thickness.
    If you want a 1.5" thick wall for drying cut the walls 2.5" thick
    You are planning to loose at least one bowl from the cores
    Better than loosing all of them or the big one.
    When you are getting an even 2.5" thickness when you wanted 1.5
    Switch to the target thickness.

    I put the coring bar on top of the bowl.
    This first confirms I have the right bar for the bowl shape.
    Then it shows where the gate needs to be set and the entry angle.
    It has always been easy for me to see where the tool,needs to be to cut by laying it on top of the bowl to be cored.
    I hope that works for you.

    Al
     
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  3. hockenbery

    hockenbery AAW Advisor Staff Member

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    Also rough turn 3 bowls to be cored and have them ready to go
    Then you can just core and core and core and you have 9 bowls


    My sequence for three bowls
    My process is to cut most of the big core first.
    Then cut the next core put a Tenno on the small core
    The cut the middle bowl free and put a tenon on it
     

    Attached Files:

    Last edited: May 2, 2016
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  4. robo hippy

    robo hippy

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    Well, if you want another video to watch, here is a link to mine:

    https://www.youtube.com/watch?v=xk-Z-scS84w

    Aiming is probably the most difficult part. Shortest version is before you start, I lay the blade up against the outside of the bowl (I take the biggest one first). How close the arc of the blade is to the arc of the outside of the bowls determines where to point the tool. If the blade is tighter/smaller arc than the bowl, you can aim pretty much down the side of the bowl as the blade will curve away from the outside. If the blade matches or is flatter than the arc of the bowl, then you aim in more towards the center. If both are pretty close to the same arc and you go parallel to the outside of the bowl, you will hit your chuck. Both Dale and I, after setting the tool post in position, like to hold the blade up above the support fingers and over the bowl in the path we want the tool to follow.

    The laser pointer is actually a good idea. It really helps when learning to know where you are. If you have a hollowing system that has a laser pointer, most of the time, they can be adapted to fit. If you don't have one, and are planning on picking up hollowing, then it is a multi use tool.

    If I lived closer, I would have you by for a hands on session. Where are the transporters when you need them.

    robo hippy
     
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  5. Clifton C

    Clifton C

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    Chris,
    I follow Al's method of visualizing with the tool on top of the bowl but then pretend that the tool is in the groove (kerf) and slide it out along the imaginary groove. This shows how far to the right the handle has to be to start the cut. Usually father then I had thought. The other thing I started doing that calmed down the tool was to set the tip of the tool about 1/4 inch above center when the tool was fully extended from the gate. If I set the height of the cutter at center with the gate next to the bowl blank, the first 2/3rds cored great, the last third would fight all the way to the bottom as if the bowl was trying to climb over the tip of the tool, and it was, because by now, the cutter was below center by about 1/2".

    cc
     
  6. dbonertz

    dbonertz

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    Chris,
    If you are making the bigger bowl to thin then you are exaggerating the tool handle to far left as you look down it for an aiming point. If the smaller bowl or core is getting to thin then you are not going far enough with the handle as you look down it for sighting. When sighting down the handle make sure your sight/aiming point is as close as you can get it. I find that if I try to sight the handle to something farther than 5 feet from the lathe then there is to much room for error. Closer than 5 feet is even better. I am sure Robo or anyone who responded would be willing to talk to you over the phone to coach you through it. If you need me then email me or private message me and I'll give you my number.
     
  7. SMawson

    SMawson

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    I found that practice more than anything else helps a lot. The more you core the easier it gets.
     
  8. Paul Gilbert

    Paul Gilbert

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    I don't have a coreing system, but do use a video system for hollowing. Do you have an old XP PC lying aroung? Hook it up to a camcorder camera, add some boat rail tubing and you have a video system that is superior IMHO to a laser. If you have the PC, it is cheaper than $100 and will give you the picture of the whole coreing bar.
     
  9. idahohay

    idahohay

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    Chris, most bowl turners have circle templates out of 1/4" plywood. Find one that best matches the curve of the knife.

    Hold the disc over your blank representing the arc you want to cut (looking down from top)

    Hold the knife so the tip is plumb with the face of the blank and against the disk. It will know be at the proper entry angle.
     
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  10. chrisdaniels

    chrisdaniels

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    I will need to figure out the diameter circle to cut out for each of my knives, I have the regular set and the small set, I like that idea that's a good one thank you. makes it easier to rotate the tool to the entry stage and more accurately aim for the entry angle like Mr. Bonnert says to do it. Thank you
     
  11. Mike Johnson

    Mike Johnson

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    I picked up a used McNaughton center post tool gate and need to acquire some coring tools to complete the system.
    I might try and forge a couple of tools or I thought if someone has some coring tools missing the carbide tips I could
    do the repairs and put the tools back to work. This is an older style center post tool gate with 3 pins. The description of the
    tool I bought listed 7/8" diameter for the post, I can't find any information on the older tools to determine which knives go with this tool.
    If anyone can direct me to an archive for the older tools or if they have any knives they want to unload let me know.
     
  12. Bill Boehme

    Bill Boehme Administrator Staff Member

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    Here is a CAD layout that I made for my use. I used the right side to determine the radius of the blades that I have. On the left side the chart shows different diameter and depth templates for each cutter. I created it to determine the maximum diameter vs. depth for each blade assuming a one-inch tenon remaining. The templates aren't exactly self-explanatory because I made it for my own use. I might work on a better version that is more useful to others. I print it on 13" X 19" paper and then can lay the cutter on top of the template to see what the entry angle is for a desired diameter and depth.

    McNaughton Blade Radius_hxx.jpg

    Disclaimer: Although I have had my Center Saver for a couple months, I haven't been able to do any coring due to rotator cuff surgery a few months ago. For the past year it's been mostly just thinking about turning and no real turning. My total experience was working with another club member coring a large bowl over at his shop and he did most of the actual coring. It was basically a new experience for both of us, but things went very well and with some forethought, it seemed like a fairly intuitive process for a couple inquisitive engineers. We probably over-analyzed everything, but that's what we thrive on.

    EDIT: If you want to print the file, it requires A3+ (13" X 19") paper. Set PPI to 101.
     
  13. Emiliano Achaval

    Emiliano Achaval

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    We had Andi Cole gave us a demo on the Mcnaughton. He gets up to 7 cores!!! Definitely the master along with Mike. The best and biggest single tip was to hold the handle UP all the time!!! I had given up on it, now I'm coring! aloha
     
  14. john lucas

    john lucas

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    I made a replacement blade after breaking one using my really poor technique ( A Mike Mahoney I aint) I didn't do a serious search for the right size metal and this one is just a little too thin. Not far off but it makes a difference in how much it chatters. Since then I've also been reading up on making spring steel so I can (if I ever get time) make the steel stronger by heat treating it to the spring steel level. I also now have a larger metal bender so some day when I settle down from this move I'll fire up the forge and make myself a whole set and get serious about this coring stuff.
     
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  15. Fred Belknap

    Fred Belknap

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    I have McNothing coring system and so far it has been mostly :eek:. I don't have much problem with alignment, my problem is getting it to cut on hard burl wood. I have bent one of the blades, it's pretty easy to bend it back to normal looking, which gives me an idea how good the metal is. As for using the micro blades so far it has been a bust. For now it is a considerable bit of money down the drain. My take on the system is that the blades aren't strong enough to work off tool rest the distance that is required for coring. I don't like being a wet blanket on this system but I have tried just about everything that has been suggested without and appreciable results. I'm thinking a system like the Oneway which supports the blade through the cut might be money better invested. My system was given to me as a Christmas present from the wife, which gives me moral obligation to get it to work.
     
  16. Clifton C

    Clifton C

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    The first turner I saw demo this tool bulldozed his way thru a few cores, but I still had to have one. Got it home and had the same results, it beat me up.

    For the first year and a half it lived in the corner. Every once in a while I’d dig it out and have another go, but mostly with the same results. Read, reread, watched, rewatched everything I could find. From the results of others, I knew the tool worked, it just didn’t work for me. So, I kept at it. When coring, I noticed that the first 1/2 to 2/3rds of the process was relatively painless, it was the last half that got me in trouble. One day while trying again, I got the feeling that the blank I was coring was trying to climb up and over the knife blade, and the proverbial lightbulb went on…

    At the end of the cut the blade was too low. I had been setting the cutter to center hight with the gate next to the bowl blank, when I rechecked the hight with the blade fully extended, the cutting edge was a good 1/2 inch below center. With the blade extended, the downward force of the cut probably dropped the cutting edge another 1/4 inch for an easy 3/4 inch below center by the time the cutter made the turn to the back half of the bowl, it was no wonder the bowl was trying to climb up and over. Now, I start with the blade 3/4’s of an inch high. The shavings flow, the blade almost self feeds, I just guide it. I’ve shown this to a few guys and the response is usually “where is this written” or “you could have told me this a year ago” or “dangit, I just sold mine last week”.
    Some folks know this, some folks don’t, hopefully it will help somebody.
    Ps. I'm usually coring 14" and up and > 4" deep.
     
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  17. Bill Boehme

    Bill Boehme Administrator Staff Member

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    What Clifton said ... plus watching the YouTube video by Dale Bonertz on using the Center Saver, paying the money for the Mike Mahoney DVD, and even reading the printed instructions are all valuable information. Two points that Dale stressed that I think are very important are setting the cutter height with the blade fully extended and you can't steer the blade ... you push it. Dale's video mentions the self feeding that Clifton described as the blade gets deep into the cut. There is clearly a lot to learn about using this tool.
     
  18. Fred Belknap

    Fred Belknap

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    What Clifton say sounds good. I did try setting the cutter above center but I only set it about 1/4" and I realize sometimes a small change can make a big difference. I'm setting on several large burls I would like to core so maybe I will try it again. The uneven on the outside of burls does present a challenge. I have managed to beat out a few cherry burl blanks which are relatively soft but most of what I have now are maple/birch and a couple unknowns.
     
  19. Bill Boehme

    Bill Boehme Administrator Staff Member

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    I think that you should save the burls for later and practice on some less interesting plain vanilla free wood.
     
  20. Emiliano Achaval

    Emiliano Achaval

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    I had given up on it. But a hands demo by a Pro was the eye opener... If Andi Cole can get 7 cores, I can get 1!! Koa wood is way harder than a lot of mainland woods, I'm happily coring Koa...
     

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