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Thread: draw bar/pin technique

  1. #1

    Question draw bar/pin technique

    Well my mortices and tenons are all cut and fitted properly, and my handmade gabon ebony pins (square top with round pin) are all made, all 36 of them. So now it is time to assemble, I am going to use a set of the LV draw pins to pull the joints together, but my question is, is it necessary or even desireable to also use clamps on these joints. I have never used this tecnique before, and have not been able to find any good information on it. I would appreciate any input you all may have. BTW this is my first piece of woodworking made totally with hand tools, including sizing and jointing the top and cutting all the mortices and tenons. I am making a table in the Greene & Green style similar to the one pictured on page 114 of Darrell Peart's book on G&G Design Elements, When it is finished I will post a picture. Thanks for any guidence.

  2. #2
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    I found that one of the big advantages to drawboring, besides the strength and durability, is that you don't have to use clamps. Spread the glue, stick it together, drive in the drawbore pins and you're done.
    "History is strewn with the wrecks of nations which have gained a little progressiveness at the cost of a great deal of hard manliness, and have thus prepared themselves for destruction as soon as the movements of the world gave a chance for it." -Walter Bagehot

  3. #3
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    That jives with what I've read...

  4. #4
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    Your first use of this technique will be on this actual fine piece? You might want to cut a practice one or two in some scrap just to get the details ironed out.

  5. #5

    drawbore videos

    There is a two part video series done by Chris Schwarz available on Youtube that explains the process from start to finish. Well worth ten or so minutes of your time. I've successfully used the method as described numerous times.

    Search for
    "Drawbore Pins Part 1" and "Drawbore Pins Part 2"
    --Mike Roberts

  6. #6
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    Jim Kingshott's "Mortise & Tenon" DVD is pretty good on discussing the technique.

    If I understand you correctly your pins are ebony with square caps all one piece? That's going to be difficult because you have to align the pin properly so that the cap is aligned square for proper show. That pin won't rotate in the joint easily especially if it isn't perfectly round. I suspect that you did not make these by driving them through a dowel plate. I would consider making these two separate pieces ( a pin and a separate decorative cap) This way the pin doesn't have to be ebony either--it won't show.

    An ebony pin also doesn't have the flex in it that an oak pin does so I am not sure I would put any offset in the hole between the cheek and the tenon.

    Here is a link to Lee Valley's draw bore pins that shows some technique. http://www.leevalley.com/wood/page.a...46&cat=1,43456
    and to Lie-Nielsen http://www.lie-nielsen.com/catalog.php?grp=1469 The Lie-Nielsen site has a very good picture of how the pin holes are offset and the deformation of the pin and a link to Schwartz demonstrating the technique. Because I don't think ebony will flex this way, I don't think you should attempt any offset in the holes (or maybe something small like 1/32").

    I would practice several on scraps of the same wood used in the project to work out the details.

  7. #7
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    Don,

    Another thought here, and I could be way off base. If you do assemble the joints with little on no offset in between the cheek holes and the tenon hole the pin won't really draw the joint together. If that is the case, then I recomment that you do clamp them to keep them tight while the glue sets.

  8. #8
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    I was going to make a similar comment to Phillips. I think that you'd be better off making the square head separate from the pin, this is certainly how G&G furniture was made. Any tendency of the pin to twist as it's driven in would be all but impossible to control which would make your square heads sit at odd angles.
    "History is strewn with the wrecks of nations which have gained a little progressiveness at the cost of a great deal of hard manliness, and have thus prepared themselves for destruction as soon as the movements of the world gave a chance for it." -Walter Bagehot

  9. #9

    Using 2 pins

    I am building an A&C Dining table and want the benefit of pinned joints and the look of ebony pegs.

    I pinned the joints and cut the 1/4" dowels flush and finished the table. With the finish complete I drilled 5/16" holes to an exact depth and squared the holes with a chisel. The pre-shaped pegs were then tapped into the opening with a bit of glue.

  10. #10
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    I'm not sure why the pin would have any particular tendency to twist, but while I've done drawboring and square ebony pegs, I've never done them simultaneously.


  11. #11
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    I'm not talking about a large amount of twist, a tiny bit would be bad. I think a peg might very well twist because as it compresses and passes through the offsets it might want to follow the grain a bit. Even the straightest grain isn't "straight".

    I could be wrong on this, but I would err on the side of caution because once you start to drive those pins you've reached the point of no return...
    "History is strewn with the wrecks of nations which have gained a little progressiveness at the cost of a great deal of hard manliness, and have thus prepared themselves for destruction as soon as the movements of the world gave a chance for it." -Walter Bagehot

  12. #12
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    I am far from an expert, but when making G&G furniture, I use an oak dowel and then put an ebony plug on top of it.

  13. #13
    If you've got the clamps, it wouldn't hurt to clamp the joint up while putting the pegs in, then you can take the clamp(s) off.

    Garrett Hack uses square pegs whittled round. He uses a small adjustable wrench to hold them aligned while pounding them in.

    Ebony can be kind of brittle, which isn't ideal for drawbore pegs. Normally you'd want something tough like white oak or hickory.

  14. #14
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    pins in tennon joints

    An alternative method, which might be safer for those quality pins, would be to assemble the joint with clamps and glue then after it has set, drill and install the pins. Of course that would take away all the fun of using those nice drawbore pins (I'm jealous) but it might be easier to align the square heads and ensure the pins don't get tight before the heads are seated.

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