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Thread: Rounding stitch-and-glue chines evenly

  1. #1
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    Default Rounding stitch-and-glue chines evenly

    Does anyone have any neat tricks for getting a consistent corner radius on something like the chine of a tack-and-tape or stitch-and-glue boat? The particular application I have in mind is the chine on a skiff-like flat-bottom hull, so side-to-bottom angle varies a little but is always obtuse (greater than 90 degrees).

    Maybe someone has a good trick with a router or laminate trimmer? I was wondering if a large-radius quarter-round (round over) bit with guide bearing and some sort of wedge for a specific angle might do the trick in two passes.
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    Matthew Long
    Bolger fan (Brick, Yellow Leaf, June Bug, Tortoise and half a Teal)
    Dreaming of a small cruiser from Atkin, Bolger, Buehler or Parker
    www.cluttonfred.info (I also like homebuilt airplanes!)

  2. #2
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    Default Re: Rounding stitch-and-glue chines evenly

    Wood rasp and sandpaper, mixed with sweat. A cardboard or plastic radius gauge to check your progress. Such hand-and-eye skills are the objective of a small wooden boatbuilder.
    Hope for the best, but plan for the worst.

  3. #3
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    Default Re: Rounding stitch-and-glue chines evenly

    ^^

    Forget the router. Your bet tool for finding that sweet fair curve is your hand.

  4. #4
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    Default Re: Rounding stitch-and-glue chines evenly

    All I would add is that a slight chamfer at the edge of the panel-maybe 1/32" over 1 1/2" before rounding will make fairing the tape into the surface a lot easier.Again,no power tools necessary as a block plane is sufficient.

  5. #5
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    Default Re: Rounding stitch-and-glue chines evenly

    initially the edges get routed fair w/ the side shape all the way around

    the round over bit stands off just a hair due to the angle between the bottom and side

    IMG_1217.jpg IMG_1218.jpg

    the second stage was to take the bottom to the side w/ a pneumatic DA using 80 grit

    the router bit sets the curve profile leaving me with glue lines to follow/mimic all the way around then hand sanding w/ 80 grit wearing elk skin gloves to protect my hands in the process

    IMG_1225.jpg IMG_4708.jpg

    GOOD LUCK W/ YOUR PROJECT

    sw
    "we are the people, our parents warned us about" (jb)

    steve

  6. #6
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    Default Re: Rounding stitch-and-glue chines evenly

    I use my favorite tool, the low angle block plane, followed by a flexible long board with 80 grit followed by 120. Fast and perfect with no chance of routing out a divot by accident.

  7. #7
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    Default Re: Rounding stitch-and-glue chines evenly

    Orbital sander, make an even pass sanding down the center point, then a quick pass angled half way toward the top, then another quick pass angled halfway toward the bottom. From there, touch the chine and wobble the sander around till you like how it feels.

  8. #8
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    Default Re: Rounding stitch-and-glue chines evenly

    Assuming plywood planking, Surform’ll cut heck outa the end-grain plies. Low-angle block plane with a keen edge is enough to rough out the radiused edge you’re after. Then a medium-coarse flat file or longboard w/80 or 100 grit abrasive to finish before ‘glass & epoxy.

    I did the hard chines on both sides of my 17’ Waterlust build this way in about 45 minutes, same after bonding deck to shearclamps & upper planks. For the hull it was eyeballed, for the gunwale I made a gage with a Forstner bit and a cut-off piece of 1/16” Delrin sheet I had laying around.

    Risk neither over-thinking the job nor potential OOps with a power tool on such a mundane task.

  9. #9
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    Default Re: Rounding stitch-and-glue chines evenly

    I just finished this job on my stitch and tape kayak. Started with a small block plane. The layers in the ply show clearly whether or not you've taken off an even amount. Then coarse sandpaper in a block of minicell foam cut length-wise with the radius I'm after. Then some finer sandpaper under the palm of my hand, and it's ready for the goop.
    -Dave

  10. #10
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    Default Re: Rounding stitch-and-glue chines evenly

    Either of the 3 large blue ones , 60 grit @ 2000 rpm.


    ...if yer havin trouble with the outside ones...trouble has only begun.

  11. #11
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    Default Re: Rounding stitch-and-glue chines evenly

    I always go for the hand tool first. Takes me longer to screw something up that way.

  12. #12
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    Default Re: Rounding stitch-and-glue chines evenly

    Quote Originally Posted by Gib Etheridge View Post
    I use my favorite tool, the low angle block plane, followed by a flexible long board with 80 grit followed by 120. Fast and perfect with no chance of routing out a divot by accident.
    Yup. I would first plane a flat all the way along the edge. This flat would split the angle between the side and bottom, and be almost to the finished depth. These angles and depths, and the width of the flat can be found by making a series of scale drawings for various points along the edge, depending on the amount of change going on.

    Once the key flat is planed two more flats can be planed, one on each side. After that, commence rounding what's left.

    If you work in short sections, or just wale away, you'll get a lumpy result.

    The key is control during the whole process. Pencil in lines to delineate the extent of the rounding and do not plane them off.

    Jim

  13. #13
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    Default Re: Rounding stitch-and-glue chines evenly

    Thanks, all. I did not say that it could not be done with hand tools or eyeballed, I was asking about tips or tricks for an amateur to use to get a very consistent result. Particularly for larger and/or multichine hulls, a way to use guides or jigs to get a consistent result would be very helpful. Are there any such guides or jigs that folks use with hand or power planes to maintain a constant angle and depth of cut?
    *******
    Matthew Long
    Bolger fan (Brick, Yellow Leaf, June Bug, Tortoise and half a Teal)
    Dreaming of a small cruiser from Atkin, Bolger, Buehler or Parker
    www.cluttonfred.info (I also like homebuilt airplanes!)

  14. #14
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    Default Re: Rounding stitch-and-glue chines evenly

    Difficult to jig a power tool to do the job because the angles change all along the length of the joint as the chine sweeps in and up at the ends. I think that the preponderance of answers telling you to use hand tools is pretty strong evidence that this method is The Way.
    Hope for the best, but plan for the worst.

  15. #15
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    Default Re: Rounding stitch-and-glue chines evenly

    The funny thing is when a guy who can't do what you're doing tells you there must be a better way, and if he had time he could figure it out and then walks away with a smug look on his face cause he knows he's smarter'n you.


    Which is probably the case if you're building a boat and he ain't.



    Jim

  16. #16
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    Default Re: Rounding stitch-and-glue chines evenly

    ...hand tools on an epoxy/plywood boat....riiiight.

  17. #17
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    Default Re: Rounding stitch-and-glue chines evenly

    Once you learn to say..."F##k it, that'll have to be good enough" everything gets a whole lot easier.

  18. #18
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    Default Re: Rounding stitch-and-glue chines evenly

    Quote Originally Posted by Jim Ledger View Post
    Once you learn to say..."F##k it, that'll have to be good enough" everything gets a whole lot easier.

    Said the man who is legend for the impeccable precision he brings to every small detail.

  19. #19
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    Default Re: Rounding stitch-and-glue chines evenly

    a way to use guides or jigs to get a consistent result
    Best guide, the eyeball; best jig, the hand.
    -Dave

  20. #20
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    Default Re: Rounding stitch-and-glue chines evenly

    Put a 4 foot long scrap in the vice and try the block plane and long board strictly by eye and feel. You'll probably be surprised.

    In the time it would take for you or anyone else to build a jig you would be able to do the entire job just as well.

  21. #21
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    Default Re: Rounding stitch-and-glue chines evenly

    Quote Originally Posted by Woxbox View Post
    Best guide, the eyeball; best jig, the hand.
    I'm damn tempted to print that and hang it in the shop!!!! Best advice in the whole string.

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