Small Projects #46: Prism Stand

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Blog entry by Madmark2 posted 05-07-2021 03:46 AM 880 reads 1 time favorited 8 comments Add to Favorites Watch
« Part 45: Cat proof screen porch Part 46 of Small Projects series Part 47: Walnut and Spanish Humidor with Hydrometer & C° gauge »

Bought SWMBO a crystal equilateral prism. Its 8” by 1-3/8” on each side.

8” crystal equilateral prism.

Unfortunately it didn’t come with a stand or any way of mounting it. We have cats so just sitting it on the window sill will wind up with it broken on the tile floor. Clearly a stand is needed.

To get a prism to refract the light you need to hold it at just the right angle. So the stand needs to let the prism rotate to the proper angle for optimum effect.

Prism rotates in stand.

I used some sapele for the ends and jatoba for the base. Again I got to use the Fast-Joint Mini with the HEART template.

HEART pattern.

The base is 8-1/2” x 2-3/8” x 3/4” (nom). The ends are 4” x 2-3/8” x 1/2”. The 2-3/8” dimension was chosen because it is exactly two multiples of the HEART pattern on the Fast-Joint Mini jig.

The end recesses are centered on the ends. I had to buy a 1-5/8” carbide forstner bit to drill the ends. I did a bunch of cipher’n trying to figure out the correct diameter and after cuss’n & fuss’n for 1/2 hour or so I had a “Doh!” moment and used my circle template to figure out the right size hole.

When I laid out the holes I also drew the outer radius.

Once the ends were drilled the bottom of the ends were routed with the HEART pattern pins. After routing, the ends were rounded on the scrollsaw (I’m getting more comfortable with that tool) and then sanded as a pair on the OBS.

The base was routed with the matching tail. All the pieces went together with hand pressure.

All the pieces were sanded at 120 grit. The faces that will be inaccessible after assembly were sanded at 220 grit. All layout lines were sanded away and burrs eliminated.

One end was glued and held for a minute by hand to let the glue grab. The glue was spread and the prism inserted. The other end was inserted, holding the prism in place. The assembly was clamped for an hour to let the glue dry.

Out of the clamps it was sanded again at 120 grit for fit and 220 grit for finish.

The bottom was date stamped and shop marked. Two slatherings of Johnson’s Paste Wax were used as finish. Felt feet completed the project.

Its not complete without feet!

-- The hump with the stump and the pump!

8 comments so far

View HowardAppel's profile


88 posts in 4153 days

#1 posted 05-07-2021 11:30 PM

Very very cool.

View Kelly's profile


3577 posts in 4063 days

#2 posted 05-08-2021 05:14 AM

Nice all the way around.

View splintergroup's profile


5284 posts in 2341 days

#3 posted 05-08-2021 02:40 PM

I have a collection of prisms like that that I scavenged from large, old copiers. Really cool to just play with and look at, but certainly entropy will prevail.

This is a cool display solution MM!

View CommonJoe's profile


17 posts in 41 days

#4 posted 05-08-2021 04:24 PM

Is that glass or plastic?
What does it do?

View Madmark2's profile


2841 posts in 1707 days

#5 posted 05-08-2021 04:32 PM

Its optical grade crystal glass. It diffracts white light into a rainbow. Makes a pretty splash of color when placed in a sunny spot.

A prism diffracts white light into the rainbow spectrum.

-- The hump with the stump and the pump!

View CommonJoe's profile


17 posts in 41 days

#6 posted 05-08-2021 04:50 PM

Thank you for the explanation.

View Redoak49's profile


5274 posts in 3107 days

#7 posted 05-10-2021 12:01 AM

I liked this so much that I ordered some to make something for the grandkids.

View awsum55's profile


1014 posts in 1627 days

#8 posted 05-10-2021 03:52 PM

Very cool, I see a bunch of these being made. Who doesn’t feel something nice when they see a rainbow.

-- John D, OP, KS

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