While making the Greene & Green
end table I found myself using all sorts of wood scraps to wrap sandpaper
around to act as a temporary sanding block.
In my hand tools are a couple of third sheet hard rubber sanding blocks that are
older than dirt. They are cracked and
brittle plus don’t really hold the sandpaper snugly so the paper always slides
around in use. As a result, they only
rarely get used anymore. With that in
mind I decided it was time to see what I could come up with as a shop built
sanding block that would hold the sandpaper securely in place, be comfortable,
allow easy changes of sandpaper and used full fractions of regular 9” x 11”
sheet sandpaper.
For most of my sanding either a ¼ sheet pad sander or a
random orbital sander is used like the ones below.
There is no good reason to duplicate the coverage the power sanders provide so after thinking about how I used the sandpaper wrapped scraps a
narrower, longer shape emerged. Working
backwards from the regular 9” x 11” sheet of sandpaper gives three 1.833” x 9”
strips from a half sheet leaving two ¼ sheet pieces for the pad sander. After a lot of paper sketches and a bunch of
dead ends it was time to draw a 3D model in SketchUp or more accurately about
half a dozen different possibilities.
One seemed to be viable enough to start some testing. Finally, after a good handful of revisions to
different parts this is the drawing used to make a full prototype.
Not surprisingly there were a few more revisions made
during the prototype build process but, in the end, the final product shown
below looks, feels and works really well.
I would like the top knob to have a better grip while being smooth to
the touch but don’t have a solution – yet.
If you are wondering why this project blog starts with a finished product
it’s because once the design is done and the sequence of operations is
finalized, I am going to do a short production run of five more sanding
blocks. That’s so I can have a different
sandpaper grit on each one and not have to change the sandpaper out when
working through the range of coarse to fine grits. With that in mind my plans are to do the
build explaining what’s going on and also highlighting the items/processes used
when making multiple identical parts.
First, since the pieces that go into the sanding block
are not very big, I want to work only from material in my scrap box. Below are the very roughed out parts for five
sanding blocks. There are a total of
four different woods; oak, cherry, walnut and hard maple.
With the rough material selected it’s time to bring the
individual blanks to a consistent length, width and thickness. That starts with ripping the two ½” thick
base pieces shown below to thickness plus 3/32”.
I normally rip pieces like this down using the band
saw. However, the rough pieces were not
thick enough to have anything useful left over so the table saw is used. The setup is below where the black wing on
the yellow magnetic fence will press against the piece being cut to hold it
snug up against the rip fence on the right.
They are then run through the thickness sander to smooth the surface
getting rid of any burn marks left by the sawn blade and get to final
thickness.
The next is to bring the 1/8” pieces shown below to their
final thickness following the same process as the thicker ½” pieces.
After that all the parts are cut to their blank size of
2” wide and 7” long. Below is a photo of
the five stacks needed for the five sanding blocks. Having consistent sizing will make steps
later on easier. In theory when all
done, I should be able to swap parts from one sanding block to another without
any problems.
Gluing the 1/8” pieces to the ½” upper base is next. They are shown in the rendering below. The bottom photo shows them glued up and in
one of my two bench vices. After the
first stack goes in the vice a second stack is glued up and put in the other
vice. I used the bench vise because while being closed the vice’s faces do not rotate and that helps keep the three layers in
alignment. The glue used is Tightbond
III which is a waterproof glue. It’s
used not because a waterproof glue is required but because I wanted a dark glue
line.
After about 20 or so minutes the glue had set up enough,
I could scrape it off with a putty knife.
Here that is in progress. A good
edge will be needed when the glued-up blank is cut to its final thickness. There will probably be a small amount of
cleanup needed but a lot less than if the glue squeeze out had not been taken
care of now.
In another 20 minutes or so the stack gets taken out of
the vice and put in a ganged set of clamps so another glued stack can go in the
vice. Here four stacks are clamped
together and will stay that way overnight.
The 5th stack is still in one of the vices.
While the glue is setting up in the vice, I worked on
other parts to be used later on. One of
which is a layer of cork. The cork goes
at the very bottom of sanding block to act as a little bit of a
cushion between the sandpaper and the wood base. See the rendering below. When I built the Danish Cord Seat the cork
used for leg glides came in a pack that was way more than I needed so it will
get used here.
As cork is somewhat soft and granular in form, I was
worried that just running it though the table saw to size might result in a
ragged edge. To minimize that a plywood
block is used as a backer and it worked out great giving me nice smooth edges.
Next Up – Angled Cut, Cork Base, Final Sizing & Locating Dowel
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