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First, put on
your safety glasses and dust mask. Then secure your
EPR block in some kind of holding fixture. I'm using
a 10" wood clamp to hold the block securely while
drilling. Mount your
13/16" bit in
the drill press so that at least 2 1/2" of drill shaft
is exposed below the chuck. |
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Now drill a
hole through the center of the block. Clear out
debris and shavings often. When getting close to the
exit point, drill slowly and preferably into a
sacrificial piece of wood under the EPR block to
avoid blow-out. Alternatively, you could drill just
short of the exit point and sand or band-saw off the
excess. |
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At this point,
your EPR block should be about 2 1/2" long. The length
needs to be reduced to 2 5/16" (critical). I'm using a 6" belt
sander to take the block down to its final
dimension. Be careful to leave a little extra length
on the block until you are sure that the block's
ends are true and 90 degrees to the hole. |
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Assuming your
13/16" hole is centered on both ends, you could use
a square to check that the ends are 90 degrees to
the block's sides. |
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This photo
shows a # 2MT pen mandrel and a pair of
bushings, purpose made for this kaleidoscope kit. |
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Also note that
the EPR block has been sanded down to exactly 2 5/16"
in length and that the ends are flush and snug
against the bushing's outer lip. |
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Here you can
see the mandrel mounted in the lathe's #2MT
headstock. There is a live center in the tailstock,
that has been snugged up to the end of the mandrel.
Place your tool rest as close as safely possible to
the turning and about 1/4" below the center line.
Also note that I've got a vacuum hose set up close
to the turning...avoid breathing that dust! |
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EPR turns best
with a skew, requires a light touch and light
shallow cuts. You can also use a flat or round nosed
scraper, but not as effectively as a skew. Parting
tools can also be used successfully under some
circumstance. Experiment with your hand tools to
find what works best for you. |
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Here you can
see that the basic egg shape has been rough turned.
I used a 1/2" round-nosed scraper with the burr
removed for this operation. You'll need a very sharp
tool and take light cuts to avoid dig-ins and a
"shattered glass" look. If you do encounter the
"shattered glass" look, switch to another cutting
tool and try again. |
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Here, I'm
using a sharp 1" straight-edged skew to clean up the
rounded surface of the egg. Again, note that the
tool rest is very close to the turning. It needs to
be close to avoid chatter and dig-ins. |
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The best way I've found to approach a turning with the skew is to lay it on top
of the piece, then gently bring the cutting surface
down until the tool's bevel meets the piece and
begins to cut. |
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A thin parting tool is being used
to finish a hard-to-get-to area. |
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So now we're
all done with the cutting and ready to sand. Always
wet sand plastic. I've put a towel on the lathe's
bed to keep it dry and rust-free. |
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This is
Silicon Carbide wet/dry sand paper cut into 2"
squares. From left to right, I'm using 240, 400 and
600 grit papers. |
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Get your sand
paper good and wet and turn the lathe's speed down
as slow as possible. You know you've got the
paper wet enough if you're getting a nice slurry and
not dust. |
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At this point,
we've gone through each of the three grits of wet
sandpaper while the lathe is running. Next, I'll
turn the lathe off and hand-sand the piece for a
minute or so in the direction of the headstock, with
the wet 600 grit paper to remove fine scratches. |
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From here,
it's a matter of personal preference as to how to
finish the piece. Some turners will use wet
Micro-Mesh. Others will use a compound like NOVUS 2
plastic scratch re- mover. |
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NOVUS works
reasonably well and will remove any remaining
scratches from properly sanded plastic pieces. |
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However, I
prefer to buff using the first two wheels of the
Beall system (Tripoli and White Diamond) immediately
after wet-sanding. A robust Tripoli buff will remove
100% of any residual scratches and the
White Diamond
is a very effective final polish. |
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Here is the
finished egg turning and the components of our
kaleidoscope kit. |
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Elements of
the kit, from top left to right are: three mirrors,
threaded mirror retaining tube, plastic color bits,
paper ring, two clear flat lenses, color bit
threaded retaining end-piece, lens retaining
spring-ring, clear curved lens and threaded
peep-hole end-piece. |
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Remove the
protective plastic covering from the curved clear
lens. |
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Place the lens
into the peep-hole end piece, curved side facing
down. Drop in the retaining spring-ring. |
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Use the head
of a finishing nail to position and "pop" the
retaining spring-ring into place, so that the lens
is held firmly in place. |
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Now set the
peep-hole threaded assembly aside and collect the
parts for the color bit threaded retaining end piece
assembly. |
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Remove the
protective plastic film from both sides of the
clear-flat lens. |
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Drop the lens
into the color bit threaded retaining end-piece. |
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Next drop the
paper ring into the end-piece, making sure it is
seated firmly against the first clear lens. |
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Now you still
have one clear flat lens and the colored plastic
bits awaiting assembly. |
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Remove the
colored plastic bits form the bag and put all but 2
to 5 of the bits into the end-piece. |
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In this
example, I've held back three of the larger pieces.
If you use all of the supplied colored bits, the
container will be too full and your kaleidoscope's
color pattern will not change when rotated. |
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Remove the
protective plastic film from the second clear flat
lens. |
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Now place the
second lens into the threaded end-piece, sealing the
colored bits in the color wheel chamber. |
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Screw the
threaded mirror retaining tube into the end piece.
At this point, the colored bits should be secured
and will not fall out of the assembly. |
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Holding the
threaded mirror retaining tube parallel to the
floor, place the first two mirrors into the tube,
making a V. Note that each of the three mirrors has
a black line marked on one side. The black lines
should be facing out. |
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Now slide the
third mirror into place, making a triangle. |
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Invert the
assembly and tap it lightly on a table so that the
three mirrors come out of the tube about half-way. |
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Make sure the
three mirrors are each extended the same distance. |
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Using a 1 1/2"
long piece of common Scotch tape, wrap the three
mirrors so they will only move as a set. |
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Here you can
see that the tape has been wrapped around the three
mirrors. |
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Gently but
firmly, slide the three mirror assembly back into
the threaded tube. Some amount of force may be
required to push the mirrors into place, but be
gentle. |
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Ready for
final assembly...slide the colored plastic bit
assembly into one end of the egg's hole. Then thread
the peep-hole assembly onto the mirror retaining
tube from the other end. |
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