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Thread: Reliability of mortise on bowl

  1. #31
    Join Date
    Apr 2018
    Cambridge Vermont
    How tight are you going with your chuck? I found my biggest mistake wast I wasn't going tight enough. For some reason I was thinking that the wood would crack like an egg. I'm sure my thought process was that you are trying to compress a tenon while you are trying to open up a mortise. I started out making my mortises a 1/2" deep (any more and the blank would hit the base of the jaws). As I get more and more experience I've cut back on the depth. I usually go about 1/4" deep now. It's easy for me to see the angle. I'm sure in time I'll try 1/8" or less but on rare occasions I still get a catch.

  2. #32
    Akex asked: "How tight are you going with your chuck?" Very tight, I think. My angle needs a sight adjustment. 1/4" to 5/16" might provide more material for holding.
    I like the strength of faceplate with glue block, but how can I ensure that it is very centered?

  3. #33
    Join Date
    Apr 2018
    Cambridge Vermont
    When I use a glue block, not that I do very often. I turn the glue block first. When I turn a flat surface on the blank for the block I either use my diamond point carbide tool to make a ring or I'll make a shallow mortise that will hold the glue block snugly.

  4. #34
    I have always preferred a fit where the angles of chuck jaws and recess match as perfectly as possible. Having the top of the bowl recess being used to snug/push the jaws down to the bottom doesn't work for me as it puts more pressure on one point than the other, which is uneven stress, and that can cause failure if you get a good catch, well, no catch is good..... Having a dedicated tool for forming both recess and tenon really cuts the guess work out. Doing it with a detail gouge or a skew is not nearly as accurate.

    You can over tighten, depending on how much wood there is on the foot of the bowl. I wouldn't want less than a 1/2 inch collar before the outside walls start for a 12 inch bowl. If you have less than that, you can expand the chuck till the collar breaks. This could still make for a failure if you are turning at high speed and have a huge catch. With a 1 inch collar, that would probably be almost impossible to break for bowls up to 16 inch diameter. Over that, I haven't really played around with enough to really know.

    I have found a glue block to be a waste of time for my style of turning. This is in part because 99% of the bowls I turn are wet wood. Yes, the CA glue will hold, but drilling a recess with a proper sized forstner bit is far more efficient. If you take some time to plan things out when cutting, it takes very little adjusting to get grain centered on the blank.

    robo hippy

  5. #35
    Please to pardon my inexperience, but how do you make a dovetail/chamfered recess with a Forstner bit?

    It's a bit amusing to me that the directions for the Nova say to just use the angle of the pointy side of my skew tool.

    edit question" how did this post float to the top?

  6. #36
    If they had a forstner bit that would cut a dove tail, I would use it, but since no one has figured that one out yet, I just drill straight in. I do drill down deeper than the recess I use for the bottom of the bowl, some times deep enough so that the blank will sit on the face of the chuck jaws. For small blanks, up to 8 or so inches, I can use my small chuck which takes a 1 5/8 bit, or my big chuck which uses 2 3/8 inch bit. Especially with the tailstock engaged, this is more than enough to spin any solid piece of wood. Not sure if I posted the link to my video about 'Mounting things on the lathe' here or not, but it is up on You Tube.

    You can get a fair degree of accuracy with a skew chisel, but that depends on the nose angle as much as anything, well, a steady hand as well. Again, that is why I have a dedicated dove tail tool. Just easier to use and more accurate....

    robo hippy

  7. #37
    Reed said: " . . but drilling a recess with a proper sized forstner bit is far more efficient."
    OK. I get it now: you drill to depth then cut the chamfer with your special dovetail tool. Could ou share a photo? Thanks.

  8. #38
    This is how I do it:

    Woke up to 10 inches of snow and it is still coming down.... People get stuck in the snow here on flat ground....

    robo hippy

  9. #39
    We had about 18 inches on Thursday and Friday. We stayed home for two days.

    Anyway, I am almost done, after working thru challenges with the recess.
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