Callum and I teamed up once again to create the mechanical model of the century; a guillotine. We first got this idea by creating a document, listing a variety of ideas for our mechanical model. However, once we saw mechanical movement 133, and thought that it looked like an upside down guillotine, we decided to use this movement to make a real guillotine (albeit, safer).

We created a rough sketch where we predicted how we would put the model together, and created an illustrator file containing the pieces we would laser cut. We originally wanted to include an axe that would move with the guillotine, but after receiving feedback on our idea from both TAs and Dr. Wettergreen, we opted to not include the axe, to ensure that we would have a working model by the project’s due date.

            

Low-fidelity prototype

We then utilized cardboard to create a low-fidelity prototype of our model. From this prototype, we learned what dimensions we would like our model to be. While we originally thought our model’s base would be 8 inches, we instead chose to have a 10-inch base to make it less top-heavy. We also slightly increased the width of the blade itself, and the space between the two pillars to make the model more attractive.

                                               

In addition, the model exposed some design issues and misunderstandings that we had with our chosen mechanical movement.  The left side of the prototype’s blade would often become stuck. We figured this could be remedied with increasing the weight of our blade, so we tested this by attaching magnets to our blade. It slightly helped out this issue, but ultimately we decided that we are going to have the handle of the blade be what guides the motion rather than the blade itself. We also decided to have the gear be a complete circle to see if we could get the blade to move higher.

mEDIUM-FIDELITY PROTOTYPE

Then, we created a medium-fidelity prototype using laser-cut wood! For this prototype, we placed two thin dowels to the sides of the blade to stop how far the blade could go to prevent it from moving far enough to snap the main bar. We also found that this helped keep the blade’s movement straight, rather than having one edge be lifted higher than the other.

                                         

However, we found that the wooden gears would occasionally become stuck to each other. We also realized that the gears will need to be strong enough to lift the heavy metal blade that we planned to cut. From this, we decided to have our gears cut metal to reduce the friction between the gears, and increase their strength and durability.

We also found that the gears would occasionally want to slip out from the dowels. To secure them, we decided to have the dowels that would allow the gears to spin to be placed through three holes (completely though the top wooden box) and the wooden pillar instead of having the dowel sit in a singular hole.

We also realized that the middle piece connecting the blade and the gear could be made shorter to increase the amount of height the guillotine could have. All of these changes were implemented to create our final prototype.

HIGH-fidelity prototype

For our high-fidelity prototype, Callum and I completely re-cut everything with the laser-cutter, using masking tape to assure that the parts did not get burnt.

            

It was also at this point when Callum had the idea to add a blobfish to the project, since every project they have worked on up until this point has had a blobfish incorporated in some way. I sketched out a blobfish wearing a medieval hat on my tablet, then traced it over in Illustrator to be cut and engraved.

                                  

We were now ready to stain our pieces using the same dark walnut stain used for our crate.

However, we couldn’t find the same dark walnut stain we used before 🙁 , so we instead experimented with different combinations of stains to see if we could achieve a similar color.

We found that using a black stain first, then going over it with a light brown stain would result in a dark brown color that looked super cool! So we stained all of our primary wooden pieces using this color. However, we stained the blobfish using a light brown color to make him stand out, and create a sort of “foreground” with our project.

We then used the water jet cutter to cut out our blade, and small gear. While the blade and small gear worked great, the TAs suggested that we also cut our large gear out of metal, since the small metal gear over time will break the large wooden gear.

      

We then decided to sandblast our large gear, as the metal we used for was filled with imperfections. However, once we placed the gear onto the project, we came to the realization that the gear was way too heavy. The wooden dowel seemed like it was about to snap, and the extra weight resulted in the pillars leaning forward.

It was then at this point when we realized that we didn’t have a handle! So we laser cut a handle, and a label for our project, which were both stained.

               

Finally, Callum and I decided to make a backdrop for our project. We used the laser cutter to cut out a piece of plywood, and stained the wood with mineral oil as we liked the lighter finish it provided (the food safe aspect is a nice bonus if we ever decide to use our guillotine for food chopping purposes I suppose).

Using the noun project, we combined silhouettes to create a kingdom background, and used the vinyl cutter to cut out the stencil. The stencil was then stuck to the plywood to stain the backdrop. This is where we noticed our mistake of staining before attaching the stencil. Since the stain was oil-based, the adhesive of the vinyl refused to attach itself to the wood. So instead we had to peel off the vinyl sticker from the transfer paper, and hold the vinyl in place as we applied a dark walnut stain.

This of course resulted in the stain bleeding through the vinyl. The castle, sun and clouds ended up looking like flames and smoke, which fortunately fit in with the horror aspect of a guillotine.

We then utilized wood glue to assemble all of our pieces together, and epoxy for the bearings (being extra careful to not allow any of it to get into the inner part of the bearing). At this point, we took notice of other projects using bearing covers to make their project look more professional, so we followed suit and created bearing covers that we used throughout our guillotine.

We also drilled a hole through our back panel to allow for the handle to go through and rotate. However, we drilled this hole far too high, so we ended up having to use a dremel to make the hole larger, and used our wooden bearing covers to hide the actual thickness of the hole.

Then, we began testing our assembled project, though, we noticed our blade getting stuck multiple times. Through some experimenting, we found that placing thin wooden rails on the sides of the blade helped keep it align, and smooth out the movement! We also found that having the pillars slightly angled to the side helped with allowing the blade to drop on its own like a guillotine.

Conclusion:

What we could have improved was our finishing of the project. Some pieces of the project have too much stain that wasn’t wiped off entirely due to our negligence. The vinyl sticker should’ve been attached before adding any sort of stain to allow for a cleaner design.  In addition, part of the backing wasn’t completely cut by the laser cutter, so a band saw was needed to slice off a small piece, which resulted in a lighter edge for some of the backing.

Still, Callum and I are super proud of this project! We accurately scoped out the project’s timeline and how much time it would take for us to achieve due to our experience working together on prior projects. We also managed to get a guillotine that actually works (granted, with a dull blade, since we were afraid of people accidentally slicing themselves), and looks cool!

Slideshow: https://docs.google.com/presentation/d/1f1_pQp_HsX6CAeoHWlRHbc4-o96m_SyYCF0mtAVazkA/edit?usp=sharing

Final Photos:

 

COST ESTIMATE

• Materials:
  • 1/4 in. x 1/4 in. x 48 in. Raw Round Dowel (Home Depot, 88¢ each): $1.76
  • 7/16 in. x 48 in. Raw Wood Round Dowel (Home Depot, $1.84 each): $1.84
  • 1/4 in. x 2 ft. x 2 ft. Sanded Plywood (Home Depot, $7.28 each): $14.56
  • Howard 12 Oz. Clear Hardwax Mineral Butcher Block Oil Conditioner (Home Depot, $9.98 each): $9.98
  • 0.3150 in. Steel Plain Precision Bearing and Reducer (Home Depot, $4.75 each): $14.25
  • BEHR Wood Stain True Black + Dark Walnut (Home Depot, $16.48 each): $32.96
  • Watco 1 Pint Danish Oil in Dark Walnut (Home Depot, $13.98 each): $13.98
  • Stainless Steel Sheet (Metal Depot, $39.60 for 1′ x 2′) Used 1′ x 1′ : $19.80
  • Cardboard Sheets (Amazon, $21 for 50): $6.30
  • Elmer Carpenter Wood Glue (Home Depot, $2.88 each): $2.88
  • J-B Weld0 0.85 oz. ClearWeld Quick-Set Epoxy Syringe (Home Depot, $7.78 each): $7.78
  • Blue Adhesive Vinyl (Amazon, $7.99 for 12′ x 13′) Used 10″ x 13″ : ~$0.01
  • Clear Vinyl Transfer Paper Tape (Amazon, $15.99 for 12′ x 50′): ~$0.01
• Labor: 40 hrs at $15 an hour: $600
• TOTAL: $726.11