Getting a Consistent Chink Gap in Log Construction
A discussion of how to make a log cabin look reasonably regular. May 27, 2014
Question (WOODWEB Member) :
We are building a demo dovetail log cabin out of 6"x8"x10' easter red cedar. The problem is all of the logs are the same dimension. The dovetails are cut with a Logosol dovetail jig and chainsaw. The spaces between the logs are inconsistent. The gap at one end will be 1" and at the other end it will be 1 1/4" to 1 1/2". We cannot get the space between the logs to even all the way across. Does anyone have any idea what could be going on?
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Forum Responses
(Sawing and Drying Forum)
From contributor E:
A couple things come to mind. First, are the logs exact in size? Any variance in height of log will create changes. Second, the jig may not be connected properly or could be moving.
From Gene Wengert, forum technical advisor:
Check the cant size for uniformity. The jig cuts the dovetail to be centered, so if the cants are tapered you will have the results you see.
From Contributor M:
I have a homemade dovetail jig, but we always work the jig from a center line on the log. If there is any variation of height the center line will balance it out.
From contributor E:
No, that only means it’s in the center of the log. Let’s hypothetically say the cut log was a 1/2" over in size. Centered up means a 1/4" over both ways and if the log under was over then that’s 1/2" short in gap. Your saying 1 1/2" differ (that's major for same dim, logs). This sounds like a setup or jig issue. Is it the same jig on both ends? Are you lining up from inside or outside? It sounds funny but my opinion is everything should be from the inside. That’s the place where jig settings should be designed from. All heels line up the logs - if cut from the outside a slightly off angle in 6" can make a huge difference in heights.
From Contributor M:
Contributor E - I was going by the picture of the log structure on the trailer made of ERC. They look to be cut on four sides, if so, and working from the center line, the space should be the same. We cut all four sides, leaving a natural edge on the outside. This makes the chinking look more natural.
From contributor E:
Centerline - is this from the inside face, outside face or true log center? Due to the way this notch is designed everything pulls to the inside, to which it should be the side everything is aligned and cut by. If all logs were ideally and truly the same maybe there would be no issue but in the real workplace that’s hard to control, even as picky as I am.
Take a piece of paper the thickness of a log, for this let's say 6" thick. Draw from the outside wall at an angle up at 30 deg then drop down 3" and draw an angle at 30 degrees down. Now measure the inside wall height. Now do this with a 6 1/2" piece. You just lost control of the wall gain/loss control because everything lines up from the inside wall. This notch is a great style but control is from the inside wall marking.
From Contributor M:
Either side can be the control side. We use the inside and screw the jig through two holes we drilled to the center line. The changing of the log thickness, by tightening the jig or loosening can vary the angle and height of the gap. If you keep the thickness of the jig a constant, and shim as necessary, you can have a consistent gap.
