With the pieces smoothed I went back through them
checking for flaws that may have come to light when ripping and sanding. Seeing no problems I marked them up showing what
parts came out of each blank. I should
mention here that the next couple steps are required only for the
leopardwood. That’s because I did not
have any raw material wide enough for the box so I have to glue up
pieces to get the proper width. I also
let all the pieces set for a week or so to make sure they are stable.
Next I set up a stop block on the chop saw and cut the
blanks into the required lengths that will be glued together to form the parts
for the puzzle box. I use a stop block since it allows me to carefully measure once and cut matched pieces all day long.
From there I spent time shuffling the individual pieces
around in various combinations until I ended up with the best grain alignment I
could get so the joints would be all but invisible. Now I can rip the pieces to the appropriate
width and start gluing them up. One of
the truths in woodworking is that you can’t have too many clamps and I pretty
used up all that I had in this size to glue all these six pieces up.
After letting the glue cure overnight I took the clamps
off and brought the maple pieces back into the work flow.
Checking the thickness of the pieces I see that I am just
a little over 1/16” too thick my target thickness of 3/8". They were
ripped this way in case they moved after cutting so I had some excess if I needed to flatten them. As it turned out
everything was in pretty good shape.
After running the pieces through the thickness sander and
keeping a close eye on their thickens I hit my target of .3775”. Before I get a lot of notes that 3/8” is not
.3775” but .375” I know that and there is a reason the pieces are two and one
half thousandths too thick. The finest
grit I have for the thickness sander is 220 and that will not give me the
surface smoothness I want.
To get both the surface smoothness I want and the
required thickness I used some spray adhesive to mount some 320 grit sandpaper
to a flat granite tile and sanded each piece smooth.
That got rid of the 220 grit sandpaper scratches and
brought the thickness down to .375 or 3/8”.
With all the pieces to the needed thickness I started
cutting them down. Some are to
exact size and some are slightly oversize depending on how I see the milling
process proceeding. To make sure I know
what piece has been cut how I write myself notes! The two long pieces at the bottom of the
photo have been through the same thickness machining process as the others and
will be used for testing equipment setups prior to cutting the actual pieces.
Here is what the top piece for the leopardwood box looks
like at this point. Note that it is
glued up out of three pieces. How easy can you find both the glue joints? That’s
the result when you take the time to do careful grain matching of individual pieces.
Next is to start routing the locking rabbit joints in the
top and bottom.
Most of the joints in this project are going to be made
using the router table and a 1/8” diameter router bit. The locking joint is cut first with the piece
on edge and then laying down. To help
hold the piece tight to the router table fence on edge I first reached for the
magnetic jig I use to apply pressure when cutting on the bandsaw or the table
saw. About that time, it dawned on me
the router lift top is made from aluminum and the magnetic jig would not
work.
So now the first step here is to make a feather
board. Not that hard, I cut a scrap pine
board at a 30-degree angle then cut flexible fingers using the table saw. These fingers will provide the pressure to
hold the piece vertical while I do the routing.
Here is what it looks like in use.
Just out of the photo are a couple of clamps holding it in place.
To start I put the bit in the router and set the cut for
1/8” deep. The full depth of this cut
will be ¼” but I think that’s too much for such a narrow bit to cut in one
pass. My rule of thumb is to cut no
deeper than the diameter of the bit. So,
a 1/8” bit has a maximum depth cut of 1/8”.
Here what the bit set for the first 1/8” cut and then for the second
additional 1/8” pass looks like.
The actual cut is pretty easy. All I need to do is press the piece down onto
the table and gently feed it through.
The actual feed rate is a matter of experience. It’s all dependent on router power, cut
depth, material and router bit. Too fast
and cut quality will degrade, bit may break or router will bog down. Too slow
and the wood will burn. Here it’s not a
matter of power but fragility of the bit and the wood being cut. The leopardwood piece is easier than the
curly maple. Both are hard but the same
characteristic that make the maple curly causes a lot of wild grain that
also varies in ease of cut.
With the first cut made I reset the fence on the router
table then made the second cut with the pieces lying face down.
When done, here is what the locking rabbit joint looks
like in the top. This piece also has a locking joint on the end.
I had just one more cut to make on the top, a 7/16” wide
dado on one end. I could have used the
1/8” bit and made several passes but wanted to minimize its use to reduce the
chance of breaking it. Instead I changed the bit out to a half inch
diameter one.
Here is what the finished cut looks like along with the
setup. I use the piece of plywood on the
right of the curly maple to back up the cut to help reduce the potential blowout of the end grain
cut.
Next Up – Sides, Dividers & Start of Ends
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