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Thread: help, big bowls, big problems

  1. #1
    Join Date
    Mar 2008
    new york city burbs

    help, big bowls, big problems

    I turned one large bowl and I thought ok, I can do this stuff, easy enough.
    I got a piece of Michigan walnut, fresh, cut as I waited, like coldcuts, I watched the guy cut it.
    when I got it home, I cut it more circular on the bandsaw because its heavy.
    I cant get my lathe much over 300-350 speed because with this heavy piece, the lathe shakes.
    I managed to get it up a few notches as I turned more off and evened it out.
    I got a catch,but I turned the speed too high witout realizing it when it was off, the thing flew off the lathe and took out a light.
    I used machine screws on the face plate, hooked it up again, another catch, the screws broke again.
    as one can see, the top and bottom of this piece is uneven.
    I was going to rough it out, then leave it a while, but the only thing that is happening is that is roughing me up.
    so what am I don't wrong and how should I approach this differently?
    (I had almost no problems when I turned my first large bowl from glueup)

    this one is tough, I don't want to launch it again, maybe 3 times wont be a charm and the bulk of this bowl could certainly leave a mark.

    Im sorry for asking such amateur questions, Im headed back for some flatwork to relax a bit.

    btw, Im using easy tools new carbide blade, so not a sharpness problem
    Attached Thumbnails Attached Thumbnails toughwalnutbowl 004.JPG   toughwalnutbowl 005.JPG   toughwalnutbowl 006.JPG   toughwalnutbowl 007.JPG   toughwalnutbowl 008.JPG  

    toughwalnutbowl 009.JPG  
    Last edited by allen levine; 10-06-2014 at 04:49 PM.
    Human Test Dummy

  2. #2
    Join Date
    Jul 2007
    DSM, IA
    The blank doesn't look like it should cause any problems by looking at it. My guess is your being to aggressive possibly. What size are the screws you're using. They might be a bit small size wise, not length wise in the pic anyway. Right now I can't remember what size I use for sure, but I think it's #14 hex head sheat metal screws. I've had some BIG catches before, but never broke a screw. I'll verify the size today and get back to you soon.

    BTW, that thing flying across the shop would send me to do some flat work for a bit too! Glad you're OK!!

    Edit: I stoppped by lowes at lunch and I do use #14 screws. They are as big as the holes in my faceplates. Using your tailstock for more support is a great idea too...I usually forget that one.
    Last edited by Jeff Bower; 10-06-2014 at 05:54 PM.
    A man is rich in proportion to the number of things he can afford to let alone. -Henry David Thoreau
    My Website

  3. #3
    Join Date
    Mar 2007
    Escondido, CA
    Two things come right to mind, Allen.

    1. Flatten a face for the face plate. Saw or hand plane, but get it flat across the diameter of the face plate. You will want as much contact between the wood and the face plate as you can muster.

    2. Bring up the tailstock to help 'pin' the piece between the two centers.

    Additionally, the largest diameter screws that fit the holes of your faceplate and at the least the length should equal two to three times the thickness of the faceplate.

    My mentor has been Wally Dickerman of Arizona. He has been turning longer than I am old and I am older than you! He was turning before chucks where used and before bowl gouges. He has embraced new things and tools as they come along (and has an awesome shop!) but still remembers, uses and teaches the basics from when he began. But all his rough turnings, small and large, begin with a face plate. As I recall, he also pre-drills the screw holes to get the best hold. Screws are #12's or 1/4" lag bolts from 1-1/2 to 2 or more inches long.

    The two things I suggested come right from my notes from Wally. I have launched one bowl and it was a crushed tenon that was the weak spot. Reminded me of rule #2!

    And taking out a light with a hunk that size is bad enough. Don't try to bounce one off your head, though.

    Some say the land of milk and honey; others say the land of fruits and nuts. All together my sort of heaven.

    Power is not taken. It is given. Who have you given yours to? Hmmmm?

    Carol Reed

  4. #4
    Join Date
    Dec 2007
    Tellico Plains, Tennessee
    Follow Carol's advice, you do need as near a flat as possible for the face plate..
    Use the largest sheet metal screws that will fit through the screw holes of your face plate... I use #12's x 1 1/2" in mine... that's the largest that will go through my face plate... if you feel you need longer screws, use them... remember you'll cut away that portion of the bowl so the screw holes will be gone....
    keep your speed as low as possible until you get the piece rounded and running true... looks like you are jusing a 1642 Jet EVS... you could start at 200 and stay there until true...
    make sure your tools are as sharp as possible, sharpen regularly when they feel like they're not cutting smoothly... My opinion for what it's worth, dull tools are more likely to catch than sharp ones.
    Use the tail stock for extra support until you get to running true.... I usually keep the tail stock up until I reach a point that it's in the way... I even cut my tenons with the tail stock up, then when I pull back, I can cut away the little nub on the tenon where the tail stock sat.
    The maximum speed I ever try to do a larger bowl at, after it's running true and has been reversed to the chuck is about 800 rpms... I know that Glenn Lucas says he runs large bowls at 1800 rpm, but I don't have the stones to do that.... I've already lost a light over the lathe, almost had an eye put out and sported a black and blue face for a few months...
    don't be too aggressive with your cuts until you start to run true, then you can open up a little more and cut a little faster,

    The most important thing is keep you mind in the process, stay in the moment and be safe... remember that chunk of wood is spinning towards you.
    Tellico Plains, TN
    My parents taught me to respect my elders, but it's getting harder and harder to find any.
    If you go looking for trouble, it will usually find you.

  5. #5
    Join Date
    Oct 2009
    Harrisburg, NC
    What the other said. I use #12 sheet metal hex head screws, just easier for me to install/remove with a power bit. Most of the time mine go about an inch into the wood unless it is a platter or some other slim item.

    Do try to have a flat area to mount the faceplate to, it can even be a little concave but never convex. Even if you start between centers (spur drive) and only flatten an area big enough for your faceplate it will help a lot (You can remove the little nub with a chisel). My faceplate is 3" so a 3-1/8 forstner bit works fine, I think your faceplate is quite a bit larger.

    Keep tailstock support until it is fully rounded as best you can.
    All tyranny needs to gain a foothold is for people of good conscience to remain silent. Thomas Jefferson

  6. #6
    Join Date
    Oct 2006
    ABQ NM
    I'll repeat Carol's advice, because she nailed it:

    1. Make sure the faceplate is flat. I've used a handheld power planer to do that on some blanks. Other times, I've used a Forstner bit and drilled a series of shallow holes to the same depth until I had a flat spot big enough to accommodate the faceplate. If the faceplate can rock with no screws in it, you're bound to have problems once things start spinning.

    2. Use the tailstock for additional support when roughing any time that it's possible, which is about 99.99% of the time. That way, if you do get a catch, the tensile forces on the screws are minimized. (Lighter cuts are also indicated, based on the picture of the bent screw.)

    3. Bigger screws, for sure. From the look of the photo, those are very undersized for the task. Use as big as can fit through the holes of your faceplate, and long enough to penetrate 1" to 2" into the blank.

    And as you have seen, it's a good idea to turn the speed way down whenever starting up an unbalanced piece. We tend to remember that advice after a time or two of chasing a hopping lathe down the driveway and into the street. On a piece like that one, I might be running as slow as 200 - 300 rpm until I got the blank rounded and better balanced.

    Take a break, catch your breath, and give it another shot. You've got this.
    When the going gets weird, the weird turn pro. - Hunter S. Thompson
    When the weird get going, they start their own forum. - Vaughn McMillan

  7. #7
    Join Date
    Mar 2008
    new york city burbs
    I thought my machine screws were light, Im going to head over to the hardware store in the morning and get at least #12.

    I know to have the face plate mounted as flush/flat as possible, but I was trying to save some depth on the piece.
    The bottom side is off a lot and I figured once I got it rounded, I would flatten it a bit more and make a round mortice to fit the chuck.
    Don't know why I didn't think to pull the tail stock up, guess I was looking at how uneven it was.
    I also think while Im at hardware, Im going to build the shelf that jet gives a spot for in the base legs, and add some weight to it.
    The lathe was moving across that hard plastic floor I have,(gladiator floor) but I cant bolt it to floor, I need it able to move a bit

    I will continue tomorrow, I will use my hand held electric plane to smooth surface as much as I can, but I see its turning from a deep bowl into a high dish/platter

    Ill put a post tomorrow after I give it shot number 2.
    (btw, I wont give up either until it shoots off and knocks me out, or Im down to a spindle)
    Human Test Dummy

  8. #8
    Join Date
    Aug 2008
    Reno, Nv
    I'd ditch the carbide for regular gouges. Carbide will catch more than a traditional gouge IMHO. Carbide has its place...but I disagree for roughing a bowl blank. JMHO.
    Your Respiratory Therapist wears Combat boots

  9. #9
    Join Date
    Dec 2006
    Yorktown, Virginia
    Here's another thought, Allen. From the looks of that blank you are trying to rough it out by standing in front of it and trying to take off the high spots with your bowl gouge. I find it a lot easier, after snugging up the tailstock, to start taking material off right next to the tailstock where the tennon/recess will be. Smooth out that area first and work your way out toward the rim, riding the bevel and shaping the bottom as you go. By doing it that way you will naturally eliminate those high spots that are beating you up now.

  10. #10
    Join Date
    Oct 2006
    ABQ NM
    Quote Originally Posted by allen levine View Post
    ...The bottom side is off a lot and I figured once I got it rounded, I would flatten it a bit more and make a round mortice to fit the chuck...its turning from a deep bowl into a high dish/platter...
    You still have lots of depth left, assuming the side with the faceplate on it now is the side that ends up being the top of the bowl. As Ted suggested, concentrate your cutting on the bottom of the bowl for now, and create the tenon (or recess, if you prefer) for your chuck. (You can do nearly all of that with the tailstock in place.) If I'm incorrect in my assumption about you wanting the bottom of the bowl to be the side where the bark currently is, now is the time to cut away the bark and make a flat spot for your faceplate.

    Then work your way from the bottom of the bowl to the rim, creating the shape you want. After you have shaped the outside to your liking, remove the faceplate and turn the blank around so you're holding the tenon (or recess) with your chuck. In the process of hollowing out the bowl, you'll cut away all the screw holes in the blank. After the inside of the bowl is shaped to your liking, you'll turn the bowl back around so that the foot is pointed toward the tailstock. That's when you finish the bottom and remove the tenon (or clean up the recess). But we'll save the steps for doing that until later...don't want to overload you with suggestions.

    I'll also echo Jim and suggest trying a gouge instead of the Easy Rougher. I can see from the photos you posted that the carbide cutter is tearing the wet wood fibers instead of cutting them. You might be able to get cleaner cuts with the carbide once you've got things more rounded out, but for now, it's not only beating you up, but it's beating up the blank (and the faceplate screws) too.

    And lastly, I'm sure you've thought of this, but if you use the handheld planer fo maks a flat spot for the faceplate, be sure you've removed any broken-off screws.
    When the going gets weird, the weird turn pro. - Hunter S. Thompson
    When the weird get going, they start their own forum. - Vaughn McMillan

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