Desk Mate: Pencil Sharpening Miniature Trash Bin With Pedal System

Ever had your desk littered with pencil shavings — or worse, the shavings find their ways into crevices and components on your desk? Here is a fun way of solving this little annoyance.

I decided to design this miniature trash bin to collect trash pencil shavings, realizing manually packing the shavings from the desk surface into the bin was no good, I integrated a pencil sharpener directly into the trash bin. To make things more fun, I added a foot pedal system to open the lid on pressing it to mimic full-size trash bins.

In this Instructable, I'll take you through, step by step, the process of designing this from scratch in Fusion 360, print and assembly of the parts. Any hobbyist who is into 3D designing, smart desk setups or just loves tiny functional objects would definitely enjoy this build and might want to make it a nice little addition to their workspace.

NOTE: I'm a beginner just starting to learn 3D designing, my first being the Thumb Ring Flashlight project (with much guidance from a friend who is experienced in the field). The 3D design of this project has been done by me (along with Autodesk Tutorials on YouTube and AI for quick explanations) so in that regards bear with me on an error I made in the build process (shown in step 5) (which I had to manually correct), I would appreciate if the design could be looked into and amended by readers who are pros in 3D design, thus I have included the STEP files for each part.

3D printing supplies (or you could use a 3D printing service):

• 3D printer

• Printing filaments (grey and blue)

Others:

• Paper clips

• Needle-nose pliers

• Super glue

Software:

• Fusion 360

This is the main part of the trash bin, it collects the pencil shavings. I modeled it and as with the other printed parts using Fusion 360 making sure it closely resembles a full-sized pedal waste bin — the tapered sides, curved edges, grooves for the pedal, a top lip and the ribs beneath it. Below is a breakdown of the design process:

Sketching the Base and Top outline (rectangles): To make the narrow base and wider top profile as in a truncated pyramid, I created two centered rectangles in separate sketches (one for the base and the other for the top). The centered rectangles were then connected using the loft tool (under the create menu), this gave a pyramid-like solid body tapering towards the base.

Adding the base groove for the pedal: To povide a space for the pedal to pass in, I made a groove along the bottom of the solid (inverted) pyramid. An initial 20mm wide, 10mm long groove and a longer 10mm wide groove extending through the rest of the area were centered on the base and extruded 30mm deep to cut (using: Extrude > Cut) the groove for passage of the pedal into the base.

Making the body hollow: I proceeded to turning the solid shape into an hollow. Using the Shell too and selecting the top surface, I specified a wall thickness of 2mm and made the hollow bin body.

Rounding the corners: I used the Fillet tool for this and made sure all sharp corners got rounded. I used a fillet radius of 3mm. This helps convey a realistic appearance to the design.

Adding the half hinge at the back: I'm referring to it as half hinge because the other half is designed on to the lid and will be joined together to make the complete hinge. To make this, I made a sketch of the shape using the Line tool, a 25mm by 10mm rectangle with a curved end and extruded it 3mm high to form a body. I extruded a 5mm radius semi-circle cut 10mm away from its sharp end. Used the Move/Copy tool to copy the body into two, move them to join the bin body and then combined them with Combine tool.

Adding the top lip and ribs: To model the top lip (the outer rim of the bin), I sketched a profile that extends outward from the top edge, then drops downward 8mm with the Extrude and Join operations. I made a hollow underside the lips using Shell function. The lip wraps around the front and sides with a gap at the back to allow space for the bin hinge. For the ribs, I sketched a right angled triangle, extruded it to be 2mm thick, made 6 copies and positioned two each on the front and two sides.

Using the Fillet tool again, I rounded all the sharp edges in the top lip.

The lid is designed to be both realistic and functional, with an added pivot point for the attachment of the push rod coming from the pedal. The mounted pencil sharpener holder makes it not only practical, but also purpose-driven for desktop or workspace use.

Sketching the lid profile: Selecting the XY plane, I made two centered rectangle, an inner one of 55mm by 65mm and an outer one of 67mm by 77mm (2mm added to avoid extra tightness when lid is closed). I extruded the outer rectangle to an height of 3mm the inner rectngle to 4mm, providing a centered layer of 1mm thickness to aid the lid in keying into the top opening of the bin body.

Wrapping a lip around the lid: I first cosidered making the lid a flat rectangular piece but then I thought of it that if the bin was to be mistakenly thrown on its side, a flat lid would open up straightaway spilling all its content, so I decided to give it a lip that falls over the lip of the bin body when the lid is closed as it would prevent easy opening of the lid upon minor falls. Using the line tool, I made an outline sketch of a loop 2mm thick around the front and sides and little portion of the back using the Line tool. Then extruded it 12mm high (4mm of lid thickness + 8mm of body lip height).

The gap at the back would be for the other half of the hinge (which will be joined to the bin body).

I then used the Fillet tool to give a round profile to all sharp corners and edges.

Adding the hinge and pedal rod pivot: Made two centered circle sketches, then made a 6mm by 3mm rectangle sketch joined to the outer circle using the line tool, combined the two into one shape using the Trim tool to remove an arc from the outer circle so it flushes with the rectangle then extruded it 23mm high. The created body was moved and joined to the back of the lid.

3mm away from the cylindrical end of the lid hinge, I extruded two centrally placed square 3mm by 3mm placed 3mm apart and 6mm tall, a 2mm diameter cylinder was then extruded from the center to pass through both poles. This is the pivot to which the connecting rod from the pedal will be linked.

All bodies are combined so the lid is a unit.

Creating the pencil sharpener housing: 12mm away from the rear of the 1mm raised bed of lid underside, a rectangular (12mm by 18mm) extrusion was made to Cut through the lid, the corners were then rounded with Fillet tool, this will be the window through which a pencil can be passed into the sharpener. To make a housing in which the sharpener would sit, a loop was traced around the extruded window, leaving a 1mm margin around it. The loop goes around the sides and back but not front and then the outline was extruded to a body of height of 32mm. The inferior end of this housing is opened, a rectangular plate of equal width and thickness is extruded in the horizontal plane to close this opening.

NOTE: The pencil sharpener housing above is tailored to the sharpeners that I use. If planning to make this project and the sharpener types around you wouldn't fit into this housing, below is the .STEP file so you can modify it.

Lastly I extruded a 9mm diameter (1mm clearance) 36mm long rod for the hinge mechanism.

One of the most engaging parts of this project was designing the functional foot pedal system, which is to mimic the mechanism found in full sized trash bins. This pedal serves as a lever that, when pressed , connects to and lifts the lid via a pivot-based linkage.

The pedal groove which is actually a part of the pedal system has been discussed in step one along with making the bin body. In this step, I will go through how to make the pedal arm, the fulcrum/pivot point and the connecting rod to the lid.

Designing the pedal arm: I made a sketch of the profile of the pedal arm using a slant rectangle, two concentric circles of 3mm wall thickness and 5mm internal diameter and an horintal rectangle making sure they all overlap. The outer circle layer and the two adjacent rectangles were joined with the Trim tool. Now to make the wide front plate of the pedal arm I skected another rectangle in front and overlapping with the slant rectangle.

I extruded the joint shapes 4mm symmetrically to give a width of 8mm and for the wide plate, 8mm symmetrically to give a width of 16mm.

At the rear end of the pedal, I made a rectangular cut through in the middle of which I extruded a rod going from ends to ends. This is for attchment to the connecting rods.

Lastly I made the pivot point rod by extruding a solid 3mm diameter 28mm long cylinder.

Once all the components were modeled, I exported each printable body as an STL file for 3D printing. All parts were printed using a standard FDM printer.

The files were then imported into Crural for slicing.

Recommended slicer settings (as given by the 3D printing man):

Layer height = 0.2mm

Wall line count = 3

Infill = 20%

Supports: For all overhanging parts — slant walls and base of bin body, the hinges and the sharpener housing.

Note, the orientation of my prints were:

Bin body - Vertically inverted, with the wider top facing down and the narrow base up.

Lid and Pedal arm: On their sides.

I printed the parts with PETG due to the need for durability against the torsion force consistently produced when sharpening pencil.

The printer couldn't print the pivot rod (for the pedal push rod to attach) on the underside of the lid, so I replaced it with cut bamboo and the glue held it so strongly together to the underlying pillars.

Upon 3D printing, the hinge for the top lid ended up being longer than the hinge on the bin body, making the rear horn of the semicircular pit end up at the mid position of the connecting rod and when balanced i.e the rod placed in the trough, the lip of the lid at the back of the lid prevented the lid from closing. I actually did thought of redoing the design for the lid and printing a new one but the cost (it relatively more expensive in my country than overseas) didn't really permit that, so anyone who can help redo this and make the correct length of the hinge will be appreciated.

I had to cut away the lips on both sides at the back of the lid and also cut the rear horn to make for a flat suface on which I glued the pivoting hinge rod, and problem solved.

One thing I noticed about using super glue was that it did melt the plastic at the portion being glue together which then solidifies back to give a strong joint.

Having printed all the individual parts: the bin body, pedal, lid and rods, the next thing is to assemble them into a functional, miniature pedal-operated trash bin, but there is just one component left to do this: the connecting rod.

To make this rod is actually pretty easy, all needed is a paperclip and a needle-nosed plier to straighten the clip and fold over the ends to form a hook-like structure on both ends, the ends will then be passed over the pivot rod on both the pedal and the lid.

Now to assemble:

— Taking the pedal and the pedal rod, I passed the pedal rod through the cylindrical hole in the body of the pedal and then placed the the protuding length of the pedal rod on each side into the transverse groove on the bin base, applied little glue to secure the protuding length into the groove, taking care the doesn't get to the pivoting portion of the pedal.

— Took the lid and the pencil sharpener and pressed the sharpener into its housing. Applied glue around its borders to ensure its properly held in place.

— Then to attach the lid to the bin body, I passed the lid rod through the hinge on the lid and glued the protuding portion into the pits on the hinge attached to the bin body, ensuring the pivoting surfaces aren't glued.

— All left is to attach the connecting rod: one hook end hooked onto the rod at the distal end of the pedal and the other end hooked across the small pivot point on the underside of the bin lid.

And that's it, all set and done.

With all the components assembled, the miniature trash bin is fully functional and replicates the behaviour of a real-life pedal-operated bin — at a smaller scale.

• Foot pedal operation: Pressing down on the front pedal causes the lid to lift upward, providing hands free access to the opening. When the pressure is released, the lid returns to the closed position due to gravity.

• Lid combined with pencil sharpener: The pencil sharpener integrated into the lid allows for direct shaperning over the bin, as the pencil is sharpened, shavings fall directly into the bin - eliminating the rigour of wiping your desk with your palm into the bin.

• The stability and handling: Despite being compact, it sits well on a desk. The foot pedal doesn't need much pressure to operate and lift the lid, thus giving optimum usability.

Overall, it's a really nice build and I did enjoy the building process as well.