Specimen Box | Display Case

My son has a large collection of rocks with no good way to keep them organized. He has them on window sills, bookshelves, dressers - I even found one in my bed! I designed this so that the rocks can be on display and out of the way, or he can lay it down to look, touch and re organize his rocks.

Materials

• 1/2" thick poplar (7.5" x 30")
• 1/8" plexiglass (14 3/4" x 12 1/8")
• 1/4" plywood (14 3/4" x 12 1/8")
• 1/8" plywood (24" x 30" sheet)
• Hinges
• Swing Latch
• Rubber Feet

Tools

• Table Saw
• Router
• 1/8" bit
• 1/4" bit
• Sander

The Sides

I cut both sides from a single 1/2" piece of poplar that was about 7.5" x 13". I rough cut the diagonal before moving to the table saw.

Cut the sides of box to length (12 1/2"). Layout the taper, then use a taper sled on the table saw to cut the angled sides. Layout the dados for the bottom and plexiglass.

The Front and Back

I cut the front and back from a single 1/2" piece of poplar that was about 7.5" x 16".Cross cut to length (15 1/4"), and then rip to width. The top edge of each piece has be beveled at 9.1 degree to match the taper of the sides.

The groove for the bottom of the box is cut with a 1/4" route bit to a depth of 1/4". I did each groove in 2 passes of 1/8" each.

The groove for the plexiglass is cut with a 1/8" router bit to a depth of 1/4". With this bit, I only removed 1/16" each pass.

The Sides

The sides are more straight forward to cut than the front and back. Set the fence the correct distance for each groove. The grooves are parallel to the tapered edge. Set a stop block on each end of the fence.

The Front and Back.

These groove have to be angled at 9.1 degrees to match the angle of the sides. To do this, I ripped small strips of wood with a 9.1 degree bevel. Place one of these strips under the piece you are routing and adjust until the correct angle is achieved (I used an electronic angle meter). Fasten these strips with a couple dots of CA glue or double sided tape. Remove them after routing.

Adjust the distance of the fence, and set up stop blocks. Route in the same way you did the sides.

Finger Joints

I chose finger joints (box joints) for their strength, especially for the lid which only ends up being 3/4" thick. However, you could use mitered corners or rabbeted corners for a simpler assembly.

I used a simple finger joint jig on my cross cut sled, and a 1/8" kerf table saw blade with a flat top grind.

Top and Glass

Cut the 1/4" plywood and plexiglass to size (14 3/4" x 12 1/8")

Assembly

Test fit all six pieces before gluing up.

I used Tightbond III for its extended open time since this is a fairly complex glue up.

Lay a bead of glue in the grooves for the bottom panel.

Spread glue in the fingers of two corners (3 sides).

Assembly these three sides and slide the bottom and plexiglass in place.

Spread glue in the final fingers and add the last sides. You can add clamps to pull the corners together, I just used a mallet to drive them into place and did not use clamps.

Check that the corners are square and let dry.

Once dry, clean up the squeeze out by sanding the outside of the box.

Cutting The Lid

Set the sable saw fence to 3/4" and cut the sides of the box first. The top of the box (plexiglass side) should be against the fence.

To angle the blade for the next two cuts I used a sliding bevel gauge to measure and transfer the exact angle made by the cut we just made.

I taped 1/8 spacers into the kerf of the previous cut to keep the box from pinching the blade on the next two cuts.

Cut the front of the box next. To cut the back of the box, the fence will have to be moved to the other side of the blade.

Make the final cut to separate the lid.

Once the lid is off, there will be glue squeeze out that you can now access inside the box. I used a chisel to clean this up.

Rip

Rip strips that are 1 1/8" wide.

Cut to Length

The horizontal dividers are 14 1/4" long.

The vertical dividers are 11 1/2" long. The ends of these pieces are cut at a 9.1 degree angle. I took the angle with a bevel gauge from the inside of the box to ensure the best fit.

Interlocking Notches

Set the table saw blade height to a hair above 9/16" (half the width of each strip).

I attached a sacrificial fence to my miter sled to minimize tear out.

I used the table saw fence to set the distance of each notch. Because each strip is symmetrical, you can cut one notch, and then flip the divider and cut the other notch at the same distance. The plans above show the measurements for each notch.

Break the edges of each divider and round the top corners slightly with sandpaper. Assemble the grid. I used a dot of CA glue at each intersection, but this is not necessary.

The grid is not glued into the box.

I recruited my son to help with the finishing touches.

Finish

I finished with Shellac and Paste wax. Any finish is suitable, or this can be left unfinished. Mask off the plexiglass before finishing.

Hinges

Locate the hinges two inches from each edge. I stuck them in place with double sided tape then marked the screw holes. Pre drill the screw holes to avoid breaking the small brass screw.

Swing Latch

Install the swing latch centered on the front of the box.

Feet

Install the feet on the back/bottom of the box.

Cut My Finger (joints) Wrong

While cutting the finger joints I messed up one end. I started on the tapered edge and it offset all the fingers incorrectly. I thought I compensated correctly when I cut the mating side, and messed that one up too.

Rather than re-cutting and re-routing new pieces I tried to salvage what I had.

I cut mating fingers from scrap poplar and glued them in end to end. I then cleaned them up with a hand plane and cut back to length.

Once completed I re-cut the finger joints correctly. They may not be as strong because there is less long grain through each finger, but they seem plenty strong for this application.

You can see in the final picture that there were some gaps in my final glue up, I filled these in with a bit of sawdust and CA glue.