Router Plane

Monday, May 1, 2017

Japanese Puzzle Box - #1 The Start

First a little history on these little boxes.  Japanese puzzle boxes have been around for over 100 years.  They are a box that can only be opened by solving a puzzle.  Some require only a simple move and others a series.  The one I will make requires five different moves to open.  They developed from furniture and jewelry boxes with secret compartments known since renaissance time.  Puzzle boxes produced for entertainment first appeared in Victorian England in the 19th Century and in the Hakone region of Japan at the end of the 19th and the beginning of the 20th Century. 
When I saw the plans for the box in the August/September 2016 issue of Woodsmith I thought that it would be an interesting project and wondered if my skills were up it.  The difficulty is that there are several sliding pieces interacting with each other and the tolerances required to make it work are very tight.  Also, after doing the Dining/Game Table I wanted to do something on a smaller scale.  There is less than 1.5 board feet in the box so it really does not take too much to build.

I started as I frequently do by making a 3D plan in SketchUp.  Even though I had a set of plans I draw the project to make sure there are no typos in the plan dimensions.  In this case it also gives me a thorough understanding of both how everything fits together and the logic behind the puzzle mechanism.  Here is the exploded view of box.  Not a lot of pieces but a whole lot of precise joinery.

Because of the tight tolerances, the selection of the wood is of particularly important.  The wood needs to be stable and dry.  That means a construction 2x4 from one of the big box stores is not going to cut it.  I went through my stash of wood looking for something special.  I considered curly cherry, birds eye maple, curly maple, ebony, katalox, leopardwood, cocobolo, gaboon ebony and quarter sawn oak.  For a variety of reasons, I settled on curly maple and leopardwood.  Both of these woods have been setting in the shop for at least a year and are dry enough so they don’t even register on my moisture meter which starts at 5%.  I don’t plan on sending either one to a humid climate so that’s not a consideration.

My plans are to make two boxes.  That’s because they don’t require much material and most of the time will be in making the machine setups.  Once the setup is done it takes very little more time to run a second piece through the machine.  Who knows, if everything goes just right I might be able to swap pieces from one to another to see what that looks like.  A side effect is that some of the photos will be of leopardwood pieces and some will be of curly maple.  It all depends when I think to take the photo. 

Here are the various pieces I started with.  As you can see I note in chalk what piece comes out of which board or how the board will be cut up to get the needed parts. 

The boards vary in thickness from just over ½” thick to 1 7/8” thick.  The plans call for all but a couple of parts to be 3/8” thick so my first step in the woodworking is to rip them down.  A marking gauge easily gives me a consistent line.  Now all I have to do is cut between the lines.

With the pieces marked I move to the bandsaw, clamp the pivot point in place and start slabbing off my blanks.

The bandsaw cut is a little rougher than normal particularly when I look at the photo.  I think I need to do some maintenance and adjustment or perhaps my blade is getting dull.  Either could cause the cut to be rougher than it should be.


Anyway, they need to be smoothed before moving on.  I do that by running them through the thickness sander.  Using an 80 grit belt quickly cleans up the cut.

Speaking of maintenance after cleaning up the bandsaw cuts I noticed that the drive belt on the thickness sander was in pretty sad shape and needed replacing. 

I keep an extra belt just in case it breaks while working so I pulled it out and replaced the old one. While I was doing that I took the time to check for lose bolts and lube the moving parts.  Here is it put back together with just the tensioning of the belt to be done.


Next Up – Glue-up, Establishing Final Thickness, Top & Bottom Routing

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