Desk Calendar Cubed

This Instructable describes the design and construction of a simple perpetual desk calendar.

The calendar is based on four cubes that have the required characters embedded in the faces.

The cubes are placed into a container that displays the current day, date and month.

The calendar is designed to fit under a computer monitor, but could be used anywhere.

It is therapeutic to start the day by solving the (simple) puzzle to show the correct information!

Whilst this Instructable describes the 3D modelling process in detail, you can just download the .stl files and print your very own Calendar Cubed.

3D Printer - I use an Original Prusa i3 MK2 - no longer available but the current version can be found here: Prusa 3D

Printing Filament - I used PLA dark wood and bone white filaments but any contrasting colours to match the intended location can be used:

Bone White Filament

Wood Filament

At first sight it would appear that there are not enough faces on two cubes to include all the required digits for the days of a month (from 01 up to 31).

However, using the following sets of digits on the cubes allows the display of every double digit from 01 to 31:

Cube 1: 0,1,2,3,4,5

Cube 2: 0,1,2,6,7,8

The trick is to use 6 as 9 by turning it upside down.

To produce 3D models I use Microsoft 3D Builder. This is a free application that is available here: 3D Builder

Creating the 3D Model

The sequence to create Date Number Cube1 is as follows:

Start a new scene in 3D Builder.

Insert a 40mm cube - Position X0 Y0 Z20 - Picture 1.

With the cube selected, select the Edit menu and click Emboss.

Make sure that 'Bevel' is off.

Change the text to 0 and resize the digit to fit the cube face.

Set the Z size to -2 - Picture 2.

Click the Emboss Tick button - Picture 3.

Repeat this process on the other faces of the cube, making sure to use the remaining digits 1,2,3,4,5.

The finished Cube 1 is shown in picture 4.

Pictures 4&5 show the cube after colouring using the Paint menu (optional).

Save the model in stl format using the filename Cube 1.stl

Repeat the above steps to create the 3D model of Cube 2, using the digits 1,2,3,6,7,8 - picture 5

Save this model using the file name Cube 2.stl

The two .stl files are attached.

The next step is to produce the 3D models of the required digits.

For Cube 1 this is carried out as follows:

Load the Cube 1 file created in step 1 into 3D Builder.

Position the cube at X0 Y0 Z0 - it will be half way into the 'floor' - Picture 1.

Add a new 40mm cube, also positioned at X0 Y0 Z0 - Picture 2

Reduce the size of the new cube to X39.9 Y39.9 Z39.9 - Picture 3

Reposition the new cube at X0 Y0 Z0 as it will have moved slightly in the Z direction.

The reduction is necessary to allow a clean subtraction in the next step. If this is not done, unwanted thin sheets will remain attached to the digits.

Deselect all objects (button at right of screen) and select the original Cube 1.

In the edit menu, click Subtract. The clean digits will remain - Picture 4.

Deselect all objects then move each digit using move, rotate and settle to position them as shown in Picture 5

Picture 6 shows the digits coloured Bone White (optional).

Save the model in .stl format using Save As and use the filename Digits 1.stl

Repeat the above steps for Cube 2 to produce the file Digits 2.stl - Picture 7

The two .stl files are attached.

The Day Cube features three letter versions of the days of the week. Three cube faces feature two days each, and a fourth only has one day. The top and bottom faces are blank.

When placed in the display container, the bottom half of the front face is hidden so only one day name is visible.

The creation of the day cube is similar to the digit cubes described in previous steps.

The main difference is that the cube is split in half while the embossing is carried out as this makes the process easier - Picture 1.

One half has the days SUN, MON, TUE, WED on the vertical surfaces.

The other half has THUR, FRI, SAT on the vertical surfaces.

Rotate the right hand block through 180 degrees (Roll) - Picture 2.

Position the left block at X0 Y0 Z10 and the right hand block at X0 Y0 Z-10 so the two halves are correctly aligned - Picture 3.

Select All and click Merge in the Edit Menu. The two halves will be merged into a single cube. Use Settle in the object menu to place the cube on the floor - Picture 4.

Picture 5 shows the cube coloured to represent the wood filament.

Save the model in stl format using the file name Day Cube.stl

The .stl file is attached.

The Month Cube features three letter versions of the months. Each face features two months.

When placed in the display container, the bottom half of the front face is hidden so only one month name is visible.

The creation of the month cube is the exactly the same as the Day Cube described in the previous step.

Again the cube was split in half while the embossing is carried out as this made the process easier.

One half has the months JAN, FEB, MAR, APR on the vertical surfaces and NOV, DEC on the top face.

The other half has MAY, JUN, JUL AUG on the vertical surfaces and SEP, OCT on the top face.

The completed model of the Month Cube is shown in Picture 1.

Picture 2 shows the cube coloured to represent the wood filament.

Save the model in stl format using the file name Month Cube.stl

The .stl file is attached.

The characters for the Day and Month cubes are produced in exactly the same way as described in Step 2: Modelling The Digits.

Picture 1 shows the Day characters and Picture 2 shows the Month characters.

One useful tip is to group the characters forming a day or month name so they can then be rotated, moved and settled as a single object. To group characters, first deselect all objects then select the three characters to be grouped and click the Group button at the right hand side of the screen.

The two stl files are attached.

The Display Container is shown in Picture 1.

The cubes are inserted and removed though the gap in the front face. The Day and Month cubes are inserted first and slid to the two ends of the container. The Date Number cubes are then inserted.

There is a slot in the rear face of the container to aid movement of the cubes.

Two shields on the front face to conceal the lower halves of the Day and Month cubes leaving just the current day and month visible.

The whole case is sloped to provide a comfortable viewing angle.

The stl file is attached. In this the case is orientated with the back face on the 'floor' (XY plane). This is the best orientation for printing.

We now have all of the STL files required to 3D print the calendar.

Slice the files to produce the G-Code for the 3D printer. I use the excellent Prusa Slicer: PrusaSlicer

Slicing details:

Cube 1, Cube 2, Day Cube and Month Cube - Dark brown Wood PLA Filament

0.1mm layer height - 20% infill - no supports.

Digits 1, Digits 2, Day Characters and Month Characters - Bone White PLA Filament

0.1mm layer height - 100% infill - no supports.

Display Container - Bone White PLA Filament

0.1mm layer height - 20% infill - supports.

Save the G-Code files on to a memory card and print all of the components.

The embossed characters in the four cubes will have to be cleaned out carefully with a scalpel. The characters are a tight fit into the indentations so care should be taken to get rid of any excess PLA. The characters mostly stay in place without adhesive, but some may need a small amount of glue.

Edit - 16 May 2022:

Robert KevinB suggested that the calendar components should be put in one download.

I have thus created an .stl file that includes all of the components.

Additionally I have added an .3mf file that has all of the calendar parts.

This has been a fun project requiring some lateral thinking in the production of the 3D models, especially the modelling of the Digits, Month and Day characters.

The calendar is in daily use (obviously!) and it makes a pleasing addition to my workstation. Each day starts with the satisfying task of rearranging the cubes in the container.

I hope that many of you will make copies of this calendar. I look forward to seeing your versions, probably with clever modifications and additions.

For detailed instructions on using Microsoft 3D Builder see my Instructable:

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