Saturday, 27 August 2016

This Is Called An Incomplete Success

This piece was inspired by the work of Raney Nelson of Daed Toolworks.  The methods used are derived from his description which was posted on his blog.  Anything that is wrong is probably due to my interpretation.

I don't mean to run out of time.  It just seems that I can never allow for how slowly I work.

This project started because of the Guild's annual 2 x 4 challenge, to make something, anything, from a standard 8' piece of 2 x 4 lumber. (See my previous attempts here and here).  This year the projects were to be presented at the April meeting instead of the the one in march.  With an extra month, I was sure to have lots of time.

One of the things I like about this challenge is that you are forced to work with limited resources. Everything must fit within the dimensions of this one board, and it forces you to plan your use of materials carefully.  I usually find myself using offcuts that would normally be thrown away in order to get enough of a particular piece.

I started out by cutting the legs from the 2 x 4.  The legs are triangular in section and I tried first to make them on the table saw.  I angled the blade to 30 degrees and made the first cut just fine.  Then I flipped the board over and moved the fence over so I would cut out a 60 degree angle to make a leg. By the time I was about 12 inches into the cut however, the saw was starting to fight back.  It was binding, wandering, and just refusing to cut.  I decided it was about time I cleaned the blade.  This helped tremendously for about 6 more inches, then it was back to the fight.  I gave up quickly this time and did the rest of the angle cuts on the band saw.  I don't know why, but my cheap table saw just doesn't like angles.

After the frame components had been roughed out the next step was to make the strips for the lattice. The exact height and width of the strips isn't really important, as long as they are consistent.  You also need to be able to easily divide the height of the strips by three.  I used three pieces of 1/4" hardboard as the height of my strips.  Having physical 1/3 pieces is important, as you will see later.

My next task was to cut my strips on the band saw and then plane them to the finished width.  The easiest way to get them all to come out the same thickness was to use a jig.

3/4" plywood base, 3/16"plywood strips on that, just far enough apart for the plane blade to get between them.  In between is a cardboard shim topped with 80 grit PSA backed sandpaper to keep the strips from moving around.  two more wooden strips on top to guide the plane and keep the blade between the plywood strips.

A screw at the end acts as an adjustable planing stop.  Was I worried that the blade would hit the screw? Yes.  At first. It took me about half a dozen strips to settle down and plane with confidence.

The plane that I used was the one I made using the Lee Valley kit, with the adjuster removed.  I have to brag a bit because the plane worked perfectly.  It's hard to check for the grain direction on thin strips of spruce and I quickly gave up trying, but it didn't matter, the plane took great shavings either way.  There were about 30 of these strips to thickness, and this was the most use I have made of this plane since I built it.  In the process, I learned a couple of things.  The first was to be careful with my knuckles when I use this plane.  Those red spots by the adjuster are blood that leaked out when I caught them on the edge of the guide strip.  The second, more important, lesson was how a small,  unhandled smoother should be held.  I have grown up in a world where handplanes were defined by Stanley planes, with rear handles and front knobs.  I never really 'got' the unhandled infill planes from an ergonomic point of view.  Now that I understand the way they are meant to be held they make a lot more sense.
Before & after thickness.
With the strips all planed I needed a way to cut them at a consistent 60 degree angle.  Custom built miter box to the rescue.

The overall length is 36", so the 20" long strips would not overhang so much that they would tend to fall off.  Why are the sides only 30"?  Because the piece of baltic birch plywood I cut them from was only 30" long.  Why is the miter slot off center?  Because I needed the extra room at one end for an alignment block which you will see later.  Why is there only one angle instead of opposing angles? Because I took this picture before I cut the second angle, and it's a good thing I did, because it took me a couple of tries to get it right and you can't see the mess I made.

Here you can see why you need to have to have something that is 1/3 of the total thickness, or in this case 2/3.  I am using the hardboard to set the depth of cut for the saw so it will stop when I have cut 1/3 of the way through.  The spring clamps are not the most secure clamps in the world but they are light and it doesn't require a lot of pressure to cut through the spruce.  There is a lot of sawing ahead and it is best not to have too much weight on the saw.

Before I can start making cuts I need to know where to cut.  I made a little marking gauge to guide the knife for the left cut.

An offcut of one of the strips is used to mark the right side of the cut.  When the cuts are made the left mark has to line up with the left side of the saw kerf.  The right mark aligns with the right side of the kerf.  That way the opening is just wide enough for another strip to fit in.

It may seem a little strange but after all this work I still didn't know for sure that this was going to work, so I decided to do a test joint before diving right in.  The first cut was set to cut 1/3 of the way through, the flipped to make a cut 1/3 through from the opposite side.  Because of the flip, the two cuts wind up at opposing angles.  Reset to cut the right side, and remove the waste with a chisel.

This is the result.  The next cut is a little trickier.  You cut 2/3 deep in one direction (120 degrees) and then 1/3 deep in the other direction (60 degrees).

When you combine these two it starts to make sense.

The last piece is cut to 2/3 depth in both directions so that when you turn it over it slides neatly into the joint.

First try.
Giddy with success I dove in to the full project.  I laid out marks on 2" centers and knifed them on the edge of a strip, along with the marks for the right hand cut.  Then I lined it up in the miter box as before, but this time I added a stop block, also cut at 60 degrees, and wedged it into place.

Now that my distance was set I could add the rest of the strips that needed the same cut and wedge them into place.

This way I could cut all 9 strips at once.  It saves a lot of time, rather than having to mark and cut each strip individually.

After that it was a lot of remove the wedges, reset, repeat.  The actual saw cuts take only a few seconds, but setting up each cut was tedious.  You can see from the picture, too, that small errors start to pop up.  I told myself that these would just help to lock everything together at assembly time and pressed on.  Once all the cuts were made I removed the waste with a narrow chisel.

The rest of the strips required cuts in both directions so I modified my marking gauge by cutting the opposing angle on the other end.  I also notched the offcut strip to fit around the strip I was marking to make it a little easier.

When all the cuts were made I took a deep breath and started to put them all together.  All in all, it turned out pretty good.

For those of you who are into numbers, there are 81 three way lap joints, each requiring 12 saw cuts, for a total of 972 cuts.  Admittedly I cheated by doing 9 at a time, so it's really only 108, but still...

My plan was to build a triangular stand with the top and a shelf both made from the lattice.  The top lattice would be a little larger than the shelf.  

I wanted to complete the top lattice by including the asa-no-ha (hemp leaf) patterns.  When they are arranged in circles they resemble flowers.  This required building one more jig to taper them to the proper angle.

The angle is cut at 30 degrees.  Taper one side of the strip, flip it, and taper the other side.  This results in a 60 degree point that fits neatly into the corners of the triangles.  I measured the length of the leg of the triangles, did some math, and came up with a length of about one inch for each leg of the hemp leaves.  Tow of the legs are formed by a two inch long strip that is cut nearly in half.

I actually went a bit too far with this cut, but it held.  The third leg of the leaf is about one inch long and tapered to a point at one end but only tapered down to the width of the saw kerf at the other end.

When you put the two together it should all fit nicely.

In reality there is a bit of trial and error in getting the lengths just right.  As usual I was starting to run out of time and I had to just get things done.  It still looks good from a distance, but up close it's a little sloppy.

I'm not going to bore you with details of building the stand because this post is long enough already and, really, it turned into kind of a disaster.  I was out of time and it was just an ugly design anyway.
In the end all but the top went into the scrap pile.  At least that part was nice enough that my wife wanted to keep it around.