any trick to remove bottom twist after assembly

Welcome! Forums Project Series Dovetail Boxes any trick to remove bottom twist after assembly

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  • #693951
    Mike Bulger
    Participant

    I make a lot of these dovetail boxes, and with kiln dried lumber from the lumber yard. It seems that everyone I make develops a slight twist in a week or two after assembly. I use mostly flat sawn lumber for these projects. Do I need to switch to rift sawn/ Quater sawn to better insure stability?

    #693957
    Colin Scowen
    Participant

    Are they doing this while in the workshop, or when they are at their final destination? How tall are the sides, and are the sides all from the same board?
    As an experiment, you might want to try making the sides and the base, but not gluing them together, then leave them both for a week or two and see if one or both have moved. I had a lid that cupped whenever the box was brought inside. Leave it in the workshop for as long as I liked, that board was flat. Bring it into a warmer environment, and within minutes there was a 1cm gap at the front. I ended up replacing it, but I checked the replacement inside first.
    Another option, if it doesn’t interfere with the way you want it to look, is to make four shallow feet, glue them on, and then, if the box twists, you can compensate for it by removing some material from the feet. I did that on this chopping board. It doesn’t remove the twist, but it does compensate for it.

    Colin, Czech Rep.

    • This reply was modified 1 year, 10 months ago by Colin Scowen.
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    #693965
    George Scales
    Participant

    I made jewelry boxes for years until the material began to cost more that the finished box would bring. If you have the luxury to pick your material, rift or quarter sawn lumber always seem to process better with machine or hand tools. I use a lot of Southern yellow pine and Tulip poplar (I am in the southern US) and I can find rift sawn in those species in even the big box stores. Some lumber merchants up charge for picking through the pile. Big box stores here could care less. I have found some really nice quarter sawn oak just going through the stack at Lowes. And the price is the same. I dovetail all drawers and I use half inch poplar and have never had a problem with them regardless of the grain orientation . Also be sure that you don’t over clamp. And check for square before the glue sets up. The ends need to be dead square before you cut the dovetails and notice how carefully Paul pairs the sockets and checks them for square as well. Every little opportunity for accuracy is another opportunity for a great finished product.

    #693966
    George Scales
    Participant

    You can make the box (drawer) a big too large and just plane it square. I make a lot of clocks and frequently have to plane the doors to fit………usually a sixteenth or less.

    #695314
    Sven-Olof Jansson
    Participant

    Hej Mike,

    If I understand “Understanding Wood…” (couldn’t resist – sorry) by Prof. R. Bruce Hoadley (Taunton Press ISBN-13: 978-1-56158-358-4) correctly, twisting in wood is usually associated changes in moisture content or tensions in it; and most typically the result of spiralling grain. (Please see attached group of photos)

    The drying of wood does apparently not result in consistent humidity over the width of logs or boards. (Please see right margin illustration in the linked paper)

    https://www.swedishwood.com/wood-facts/about-wood/wood-and-moisture/

    If there’s a gradient in humidity, then wouldn’t further processing of the wood increase the risk for warp, in addition to what changes in humidity would provoke; and if so, will how the logs are sawed avoid the warp? Perhaps there is a tendency to reserve quarter sawing and rifting to logs with more straight grain, and flat sawing (radial) to the less precious cross grain ones. Then of course, flat sawed construction wood will occasionally come out as quarter sawn (a 5″ thick board can be ripped into boards of that width).

    With a modification of methods shown by Mr. Chickadee, I’ve flattened boards along cross grain (using a straight edge to follow the grain and then a spirit level along the edge). This far the method has worked, though it is hard work

    Sven-Olof Jansson
    London, UK; Boston, MA

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