Thor’s hammer is named Mjolnir, which means the grinder, or crusher. Supposedly forged from a dying star it’s a pretty sweet weapon. I decided I wanted my own Mjolnir but not one made of plastic or something lame like that. I wanted you to pick it up and be impressed by the weight of this thing. It’s actually been a project I’ve been working on for about 2 years. To make it all it once wouldn’t have been that hard but it would have cost a lot more and gathering the materials the way I did enabled me to spend less than $30 to make it!
The first thing I did was start getting familiar with the shape of Mjolnir. There are a lot of different versions each with its own flair in the shape, bevels, and ornamentation of the rectangular hammer head, as well as the length and ornamentation of the handle. In the end mine doesn’t resemble any one of them exactly but is a mash-up of a lot of them with my own design added in.
I knew the final design would be made of metal but I wasn’t sure how to go about making it. The first thing I made was one made from wood in about an hour. The picture below is the first one I made from scrap 2″x4″s, chrome duct tape, and some faux leather from an old bag I bought at a thrift store for a couple bucks. Even this version was pretty heavy. Perfect. It helped me get a grip for how the dimensions I’d chosen looked in real life. 3-D modeling is good, but real life is better.
This is the model in3-D space and an engineering drawing I’d created.
After seeing it in real life and thinking about how I would turn this into a final steel version I decided I wanted to modify the dimensions a bit. I went back to the computer and modeled another hammer, but this time with a plan for the finished hammer.
The entire thing couldn’t be made from steel or it’d weigh close to 200 lbs! So steel plate is the next best option. This leaves the inside hollow. When I started this project I didn’t know much about welding so I guessed I would need some sort of guide/ template to help hold the steel plates in place as I was welding so I designed the 2nd prototype to be the wood frame I would use. You can see this version below is less ornate because it’d designed to have the steel plate put on top of it.
After designing I made the wood hammer head part with 2″x4″s that we had lying around in the woodshop.
The next step was the handle. I worked a summer in Alaska and had chain sawed some thick Alder tree branches to bring back home. They have some sentimental value to me and I liked the idea of having that around as a reminder of my summer there. I bought a half-inch threaded rod from Home Depot to use as the core of my handle. This would make the handle strong and also serve to anchor the handle to head by attaching to the top circle cap. The cap has 2 nuts welded onto the bottom that the threaded rod screws into pulling the handle into the head. The threaded rod also serves as a place for the ornamental wood knob on the bottom of the handle to attach.
Making the Handle
The starting materials. An Alder branch, 1/2″ threaded rod, and nuts.
I couldn’t drill a hole long enough to go through the entire branch so I cut the branch into pieces then drilled the hole. I used a drill sized just slightly smaller than the threaded rod, this caused the metal threads to act as a tap and die for the wood.
The fit between the drilled hole in the wood and the threads was so tight I needed to use a clamp to give my self enough leverage to turn the wood onto the bar. It was tiring and caused a lot of friction and heat to generate in the threads and wood.
After getting enough of the wood onto the bar I used a little creativity to get it to sit on the lathe.
etching the plates
After turning the handle and knob I set to work on making the steel plates that would fit over the hammer head. I bought a scrap piece of 1/8″ thick mild steel plate that had enough square inches for all the pieces I would need. If you can find a scrap area at a machine shop or similar place you can usually find a good deal if you know exactly what you’re looking for. I paid about $12 for a piece and used up almost all of it. I chose mild steel because it was inexpensive and had the right “look” to it. Kind of a gun metal grey that wasn’t too shiny but not too dull either. I didn’t want it so shiny people would assume it had never seen battle! I cut out the plates I needed with a hydraulic shear, this was a mistake though, if I was to do it again I would use a CNC plasma cutter for more accurate cuts.
After cutting the plates to the dimensions I needed I drilled holes in them to be able to screw them on to the wood where they would sit. I was thinking that this would make it easier to weld them all together in the future. I didn’t have a lot of experience welding then and if I was to do it again I wouldn’t feel the need to drill holes in each piece. Now that it’s done however the holes are not all that noticeable and its kind of a sentimental feature that reminds me of where I used to be.
The next step was to etch the Norse designs into the side plates. Not all Mjolnir versions have these designs but I wanted to have them because they look dope!
After some adobe photoshop and illustrator magic I converted the designs into a usable silhouette file. I had some help from a machine shop transferring my file to G-code and a CNC machine.
I mounted one of the 8 plates I would need to etch in the CNC machine and let her whirl.
It took almost 3 hours to finish.
The etching was very shallow, you could just barely feel it rubbing your finger across it. If you look closely you can follow the path of the endmill.
I decided I didn’t have the time or patience to make each etching using the CNC machine so I had to find a different way. I wanted to eventually polish the dark corrosion off the steel as well and I worried that the CNC etching would be buffed off as well because of how shallow it was.
Eventually I found electro-etching. Having never done it before I did some research and did some experiments.
I frankensteined some 5V wall adapters and did electro-etched a dinner spoon. Whatever is in the metal is released into the salt solution and after a while it looks like some primordial soup. I was surprised by how easy it was to set this up.
Next I started practicing etching designs into steel. I was trying to determine how intricate my designs could be using this method. The constraints you run into are how intricate you can make your mask and how good of a seal you can adhere your mask to the steel.
You also have to clean the surface of the steel exceptionally well. It’s a good idea to buff and polish it beforehand. Without doing this you can have pitting and bumps form instead of a uniform layer being removed.
After running several experiments and getting my process down to a science I was ready to electro-etch the Mjolnir plates. I used an old X-box 360 power supply as my voltage source because it had the highest voltage of all the power adapters I could find.
welding the plates
Now the fun part, welding the plates together. The wood prototype was helpful but not as essential as I thought it would be. By the time I got around to welding this together I had experience welding lots of different projects, like my welding table, truck ramps, sculptures, and others.
The steel pipe on the inside bridges the top and bottom of the hammer and provides rigidity so no bowing occurs when you tighten the handle on.
I used masking tape to try and hide the Norse electro-etchings from welding spatter. This worked only marginally well.
After I welded all of the seams together I knocked off all the slag, grinded down the welds to make them smooth, sand blasted the dark oxide layer off and buffed it smooth and shiny.
staining the wood and covering the handle
The last step was making a leather cover for the wood handle. This part took me a long time because I was doing this project very inexpensively I could just go buy leather to make a handle or pay someone to have it done. Neither did I want it to be faux leather. This is a legit Thor hammer and I did not want any faux leather. Unfortunately real leather is hard to find for free. Most things that look like leather are not real leather. But one day I followed up on a KSL ad that listed a horse corral was about to be torn down, I went to check it out and found a super old dry and dusty leather welding jacket. The picture below is even after I pressure washed it.
Now the task is to re-condition the leather so it looks and feels nice again. After pressure washing I tried 3 different cleaning solutions and found that water and baking soda worked the best. A ton more dirt and dye came out of the leather after this. Leather is a porous material and you need to replace the natural oils especially after the cleaning process I just used. I did a little research and then made my own conditioning salve from beeswax and olive oil. And it worked!
Next step was to sand the wooden handle again and then stain it.
I cut the leather in strips and sewed the strips together creating one long wrap. I also made a separate strip to use as a wrist strap, then I braided it around the handle in an over under pattern and was done!
Total this Mjolnir weighs about 30 lbs and it’s strong enough to throw through a wall.
I may electro-etch something into the side one day but I haven’t figured out what I want to put there yet.
electronic circuit schematic
finite state machine diagram
testing stepper motor direction and tracks
My 3-D model of the robots frame. These pieces were cut out of acrylic and press fit together.
shooting ping pong balls
testing turret movement
testing mobility and centering ourselves in the arena
As part of a 3-student team I developed and built a force sensor used to determine the drag coefficient for an odd shaped object. Below is our final report including our conclusions and results.
PIPSQUEAK SLIDE PRESENTATION
Having a foundry is just an incredibly awesome thing everyone should have. The possibilities are…endless. I have not finished building my final foundry but this is where I started. I followed Grant Thompsons youtube video you can watch here.
This foundry worked great, but it has some flaws. Having a charcoal powered foundry has its limits. It takes quite a bit of stoking and routinely adding more coals to keep the foundry burning at a high temperature. It’s also a little small.
It was pretty cool to melt some aluminum. The first time i lit it up I melted close to a hundred cans. I learned that liquid aluminum is actually corrosive to steel. My crucible was fairly thin and the aluminum dissolved several small holes and then leaked out into the foundry. The next version of the foundry will have a much thicker steel crucible.