Welcome! Forums General Woodworking Discussions Fret Sawn dovetail waste removal results in excessive tear out

Viewing 12 posts - 1 through 12 (of 12 total)
  • Author
    Posts
  • #425197
    Kevin Farris
    Participant

    I am not opposed to methodically chopping waste from my dovetails as they come out as clean as I can make them and I am quite pleased with the result.
    I have been playing around with fret sawing out the waste (to move things along a little faster). I am currently leaving about 3/32-1/8″ of material to be chiseled out.
    I have tried in maple, ash, oak, and poplar, and each time I experience excessive “childs tooth” socket tear out. I am using very sharp chisels (25 degree) and trying to nibble off small amounts, but by the time I get to the shoulder the breakout has already started.
    Is there a technique to avoid this or is this method prone to more tear out? Even though nobody will see it, I do not like knowing it is there.

    #425215
    Clifford
    Participant

    I have experienced the same thing and look forward to any insight! I also include black walnut and alder in the list.

    #425230
    Edmund
    Participant

    This makes no sense to me — maybe I don’t understand what is being said.

    The OP is sawing out waste from a dovetail, leaving an 1/8″ or so to be chiseled out. Then, during the chiseling process, somehow tearing out occurs (here I thought tear-out was a planing issue, didn’t even know it was possible with a chisel), and yet the OP is claiming the saw is to blame?

    How does the last 1/8″ know if all the previous waste was removed by a chisel or a saw? …especially since a saw is just a bunch of small chisels cut from a larger plate of steel…I have to hear this explanation.

    #425405
    SmokyRick Crawford
    Participant

    Are you cutting from every edge toward the middle? If not, this may help. This is all that I can think of from what you describe.

    In the middle of Northern Illinois, USA

    #425458
    mictau
    Participant

    Hey Kevin,

    I’m not sure there is a great solution to this. I think the normal approach of shooting for the sky while paring is problematic in this case. The extra torque created as you hit the top of the unsupported fibers increases the likelihood you will rip out the end fibers making it really hard to get a clean cut started.

    The only time I’ve had much success with this is if the dovetail is large enough that I can come in from the top, bevel down, and then working parallel to the width, slowly bring it down until I have enough room to make a clean paring cut at the base of the fibers. Once I have a start I’d pair like normal. Although I make a lot of smaller pieces so this often is not an option.

    Another thought, although I’ve never actually tried it, might be to use a needle file to take the waste down closer to a 16th or 32nd before you start paring. It seems like if you bring it down enough you could significantly reduce the issue with the unsupported fibers.

    Mike

    #425498
    Kevin Farris
    Participant

    After sawing the bulk waste parallel to the knife line, I have been using the bevel away from the knife line on side A of the board, essentially paring the waste to the knife wall about half way down the wall. This works normally, as if I had chopped out the waste.

    When I flip over to side B of the board, the left over waste (now unsupported) is where the difficulty arises.

    I start paring/shooting small increments of waste (bevel away), and by the time I get to the knife line the torque has already started the breakage below. The resulting shoulder is still clean, crisp, and undamaged. It is about 1/16″-3/32″ below the shoulder where the breakage occurs the remaining way to the half way point where I would meet the side A stopping point.

    Smoky Rick, I may try to do what you describe with a narrower chisel. Shoot to the sky, but at an angle from the edge of the waste.
    I am located in Belvidere, also in the tundra we call the middle of Northern Illinois. Quite enjoyable weather lately, Brrrrrrrrrrrrr.

    It just came to me that I could probably shoot the to the sky with the saw on both sides and get closer to the shoulder, leaving a more controllable hump in the middle. Maybe I need to work on my fret sawing instead.

    #425574
    deanbecker
    Participant

    Are you creaping up on the shoulder or cutting the whole 1/8.
    I cut close to the shoulder and pare the last out with a circular motion using the corner of a really sharp chisel.
    If i leave too much i cut 1/64 th or less at a time back to the shoulder.
    Just pare off the edge every time. If the wood does t curl off the edge of the chisel it is dull.

    #425705