Heat Box for Industrial Clay

After completing the DIY course at CMU, I was invited to TA the class the following year. The class size increased from 40 students to 60, so we needed an additional heat box for an assignment involving industrial clay. Here’s (most) of a how-to. I sort of neglected to include how I put on the hinges, but that’s pretty straightforward.

You’ll need the following:

The first thing to do is to cut all the panels to the correct size.

  • Left & right sides: 18″ x 18″
  • Top & bottom: 29.5″ x 18″
  • Front & back: 19.25″ x 29.5″

These dimensions worked for my 19/32″ thick plywood sheets. Based on how things are put together, the back and front panels need to be adjusted in the height dimension (19.25″).

I don’t have a table saw at my place, so what I did instead to cut really straight lines is to clamp my straight edge to the plywood for cutting with a circular saw.


Use the thickness of the Sharpie o your advantage! It tends to be pretty close to the thickness of circular saw blades, so line up those teeth with the cut line.


Apparently finding a length and dividing by two is above my pay grade. These two sheets were supposed to be the same length, cut from one sheet of plywood.


Well, after fixing the length of the sheets, I tacked down all the nails along the edges a 1/2″ in from the edge of the plywood sheets and tried to get them evenly spaced with at most 5″ between the nails.


Apply glue to the edges that are supposed to be joined…


All edges glued and nailed together. The plywood was just slightly more bowed, so I opted to use a bar clamp to keep to edges tightened down while the glue dried.


The back was put on pretty similarly: evenly spaced nails, glued faces.


I’ve somehow managed to survive without a compass to draw circles, so I just used my calipers to measure the size of hole to cut (2″ for my lamp) and scribed it to the center of the top of the box.


If I had a 2″ hole saw, I probably would have used that here, but instead I just drilled a while bunch of holes to I could cut through them all with the routing bit on my Dremel.


After cleaning up the hole with the sanding drum, I added 1/4″ chamfer on the underside to accommodate the taper of the lamp bell.

I sort of just forgot about documenting the last couple parts (putting in the insulation, foil, hinges, and handle), so… here’s a picture of the final product:


Oh… and here’s a closer picture of the door-prop:


If you’re interested in putting the same door-prop on yours, I’ve uploaded the STLs to a Thingiverse “Thing.”

As a final note, a 60W light bulb works fine, but an 80W would be better if there’s a lot of clay or if the door needs to be opened and closed really often.


Sharpening a Reel Mower (Push Lawn Mower)

My WordPress is long overdue for updates, so I’m just going to do a bunch at the same time while I have a little break from schoolwork.

This post won’t necessarily be helpful as a how-to post, and more of a this-is-possible post, because it’s way easier to learn this from a video or from someone else than it is to learn from pictures and text, but here goes.

I started a little company (really just some online postings) for a sharpening service while I’m in Pittsburgh, because for some weird reason, I couldn’t really find anyone in the area who offered knife sharpening. Anyways, I got a call from someone asking if I could sharpen a push mower, so after watching some videos and reading an Instructable, I figured out how. Before I dive into steps, if you want to follow along, you’ll need the following tools:

  • Flathead screwdriver (popping off e-clips and adjusting blade)
  • Valve grinding compound
  • Grease
  • Cordless drill (makes things a little easier)


So the first thing to do is to pop off the wheel cap, e-clips (retainer rings), and wheel. This way, I could rotate the blades without the wheels spinning around.


After that, I popped off the little gear. Inside it, I could see how the ratcheting mechanism worked. There’s a little almost trapezoidal shaped metal bar that sits in a slot in the shaft of the blade assembly. Pushing the mower will engage the wheels with the blade assembly, spinning the blades, while pulling the mower will disengage the two parts, so the blades stop spinning.


There are two screws on each side of the mower that adjust how close the stationary blade is to the spinning blades. For sharpening, I adjusted them a little closer together such that the spinning blade assembly could still rotate but with quite a lot of force. The blades will be used to grind each other to sharpen everything up.


I loaded all the edges with the valve grinding compound, which is basically just a bunch of sand in some sort of past-like suspension. The abrasive will allow metal grinding that sharpens the blade edges.


One of the videos suggested using a cordless drill to rotate the blade assembly. Unfortunately, my cordless drill chuck didn’t fit over the axle. The Instructable suggested flipping the ratchet assemblies (left to right and vice versa) to “run” the mower backwards, so that’s what I ended up doing instead. Important note… spin the blade assembly backwards and not forwards, otherwise you’ll be dulling the blades instead of sharpening them.


After running the blades backwards for some time and cleaning off the valve grinding compound, I could see that metal had been removed from the leading edges of each of the blades.


After cleaning off all the grinding compound, I adjusted the blade distance again such that the blade edges were touching along the entire length but not too difficult to turn. To make sure everything was nice and sharp again, I grabbed some paper, stuck in between the blades, and checked the sharpness for each of the blade along the entire length of the mower.

The last step was to clean out the old grease from the gear and ratchet assembly, pack with new grease, and reassembly everything (making sure the mower blades spin in the correct direction).

Hope that was useful to someone. Again, there are plenty of Youtube videos, and they’re probably much more helpful for learning how to do this.

EachPick for ProMAT 2015 in Chicago

EachPick gripper holding a tissue box.
EachPick gripper holding a tissue box.

Between September and March, I was tasked with creating a flexible gripper to handle a variety of objects using Grabit’s core technology, Electroadhesion. After some 14 revisions of the gripper, this particular one ended up being sent to Chicago for the ProMat materials handling conference in March. A video of the gripper in action can be found here on Youtube.

I actually ended up making 4 similar units of the EachPick gripper. Two of the units were for mounting on the robot, and the other two units had a handle with a button for manual operation.

The fabrication techniques used for each of the units included aluminum machining, 3D printing, vinyl cutting, laser cutting, and vacuum forming. The robot-mounted versions of the EachPick gripper are controlled using a Pololu Maestro Servo Controller through TTL communication. The Denso RC8 controller handles the timing of the opening, closing, and operation of the LEDs and high voltage along with the motion of the robot arm. The handheld versions of the EachPick gripper are controlled with an Arduino Uno, stripped from the programming board.

Climbing Shoe Patterns

Here’s a shot of some of the shoe patterns that I worked on for about two weeks. In order to get the two most important parts of a climbing shoe correct (the toebox and the heel cup), I focused on the two halves of the shoe separately. The final patterns, the two in front, were combined to make some prototype shoes that were climbable. After that, my friend and I headed to Las Vegas to meet up with someone who made custom climbing shoes as a side job. We’ll be getting those in a couple weeks.

Upstart Video Competition

Hey guys,

So I’m in the midst of a little video competition on Upstart to get some more money from our backers for the startup. If we win this competition, which ends at 23:59 PST, we’ll get a decent chunk of change to work with for more prototyping. It would be greatly appreciate if I could ask for 2 minutes of your time to hope on Facebook and vote for our video. (It’s the one with climbing shoes.)

Thanks a bunch!


Upstart Video Competition

SFT Climbing

So at the beginning of June I started working at SFT Climbing with a friend of mine. The two of us founded the company to create a completely new kind of climbing shoe that can be adjusted to the user’s need. Instead of having to own multiple pairs of shoes for different applications, the idea is that a climber will only need to own one pair of these shoes. The shoes will be able to be adjusted from flat and comfortable to curved and fiercely aggressive. 

So, I’ll definitely be cross-posting some of our work to this page, because rock climbing is a sport that I am extremely interested in. At this point, all the work is super hands-on as we are prototyping. Pictures and videos will follow as soon as we determine it’s okay to release to everyone. I hope you guys are interested to see what’s coming!

SFT Climbing