Hmm - Knots

   A real downside to using the cheap SPF construction material for this project is the simple fact that the wood is low grade.  In addition to being fairly soft, it has quite a few knots.  In hindsight, I probably should have been a little more careful in thinking through layout around some of them.  Here is the first challenge that has come from that.

  Inside the through mortise, I have been able to chop away the fibers cleanly, exposing the branch.  But that won't clean up nicely with a chisel, particularly because the dark black ring shows that it will come right out.   I'd rather not fill all of that space, particularly because that would leave a very thin remaining wall for the mortise.

 This detail shows where the chisel down just gets stopped by the tougher grain of the isolated branch.   I want to use that branch stock as a plug when I fill in all the knots a little later.  For now, I just need to clear it out of the mortise.

To do that, I use a flush cut ryoba from the Japanese detail saw set sold by Lee Valley.   I find I use this set far more than I use my larger ryoba and dozuki set.  I tend to prefer Western saws, but for some cuts the ability to use a pullstroke flush to the work surface is invaluable.  

The ryoba makes short work of the piece, and the result really is a lot like a perfect fit plug.  From here, I move on to cutting the rest of the mortises - and dealing with more knots.

On this one, the cut simply went through too much of the branch stock, so the plug is not viable.  That will make it more complicated to fill, but it also means it is only cosmetic.   That will probably be the case for two more - somehow I managed to get the knots close to the mortises.  

But there is one that really has me thinking I should have done this project in clear maple.  This knot is again on the wrong side of the mortise, making for a thin wall.  It is also larger.  The only saving grace is that it is much worse on one side than the other.

There is no plug to this one, the branch had not died, so it doesn't come out - cleanly or otherwise.  The force of the mortise chisel causes it to break into chunks.  However, I want some of those chunks, so I glue the larger ones back in when done, then cut them flush with the ryoba.

Somehow, the problematic knots all ended up together.  This is a view of the double mortises from both end boards, stacked one on top of another.  On the left, below the last knot you can see the sidewall of the first one.  It will probably end up being another evening session just filling and cleaning up the knots.  But for now, the mortises are done.

The next challenge is going to be fitting and cleaning up six mortise and tenon joints in a fairly large frame.

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