Wood Joinery with Techno CNC

Last time I was lucky enough, and/or the CAD/CAM job was really neatly done. Outcome: the wooden container came out to be a beautiful piece with finished details.

This time the techno CNC sorcery won, I could not make a seamless wooden joint after a several attempts. As always I worked on the assignment on weekend when the shop is usually empty. I did some sketching first with paper and pen, looked at the reference examples on Subtraction class page, and then made vectorworks drawings:


I tried Oval-shoulder halving and Tenon halving with ellipse and rounded square shaped window. For the oval shoulder I tried two different drawings: One with zero tolerance and other with a 0.01″. The pieces with zero tolerance needed a lot of sanding, and the ones with 0.01″ tolerance were somewhat simpler to assemble.

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It required considerable efforts on sanding the surface areas and hammering the pieces to fit them together, but this could have been a lot better and easier with more tolerance.

I ran into and learned a lot from two issues-
1. Stupid mistake I did in CAM: I made a significant mistake in the parts that had oval and rounded square windows. In setting contour and engraving orders, I had put the engraving first, then outside contour for the whole piece, and then the contour for window inside the piece. As a result the piece was not stable when the oval window was being cut. I had to pause the router and fix the piece into the spoilboard with two screws so that it wouldn’t wobble. The oval window got completely spoiled though, but I was able to manage it in time for the square window.
2. Bad quality of the material: The ply had an uneven, kind of burnt layer underneath the oval window piece. The layer got chipped off as engraving reached a certain depth.

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Seat-back experience for ordering food

The assignment was to design an experience for ordering food. The passenger should be able to order following on a seat-back panel at arm’s reach:

Soda (4 types), juice (2 types), coffee, tea water
(and ice/no ice, can/no can, coffee w or wo milkv(whole or skim), sugar,)
Sandwich (3 types)
Salad (2 types)
Dressing (4 types), mayo/mustard
Snacks (4 types of chips) or nuts or fruit
Dessert: cookies, yogurt (3 flavors)

And also:
Identify quantity
Place their order: 3 payment options or cash
Cancel their order
Change order
Or signal not to be bothered.

We categorized the menu based on subsequent choices a user would make while placing their order. We used post-it notes to create the flow diagrams:


The max size is almost same as 15″ MacBook, so I used Apple Keynote to create the mockup screens and this vide:

The top menu has four categories which further show subcategories in the secondary bar. Add-ons such as sauces, dressings, ice, milk, sugar etc. are context-specific and appear only when a particular dish/ beverage is selected.

The user can order multiple items together, cancel the entire order, and even try new dishes without having to go through the whole process.

Counter: App Prototype

Balsamiq is a fun way to make quick smartphone app prototypes and I enjoyed sketching in the notebook and simultaneously rendering the prototype screens on Balsamiq.


I considered following points while translating the earlier assignment into a smartphone app:

  1. The physical device had a tactile feedback that made it a unique and beautiful. The smartphone should deliver similar sense of acknowledgement.
  2. The smartphone app can take advantage of what could not be (and should not be) achieved by a simple physical object: Connectivity, tracking and perhaps memorizing user’s behavior.

Following are the sketches of digital version:
The first row shows a landing screen with Add New action screens next to it. User can write a title (and select one from the list of already used titles, as they start typing), select whether to count Up or Down, assign start and stop points, and attach a background image.

The second row shows the list of ongoing activities and a specific entry from that list (Coffee). Third row and the last screen show further explorations within the activity, divided into three categories: Settings (edit, delete), Performance (count up/ down, undo, see performance graph- this is default view within a selected activity), and Share(share your performance on social media such as facebook, twitter, instagram, google+ etc.). Smartphone would vibrate to provide a quick haptic feedback when user counts up or down- this retains the impact of acknowledging every single step the user takes towards achieving their target.

New Mockup 1

I used a couple of amazing iPhone mockups and iOS elements vectors from here and here, to generate lifelike visuals of the prototype:



Techno Router: Making a wooden container on CNC

Of all the machines we’ve learned so far in Subtraction class, techno router is the one I enjoyed the most. It felt like using a scaled up Othermill router where bed size has been enlarged considerably from 5.5 X 4.5 inches to 8 X 4 feet. Also this assignment involved the most hacks and impromptu workarounds than other machines.

I thought of complex ideas initially, such as making a simple chair or stool with a few joints, but soon dropped that idea as making drawings in vectorworks for the first time was really tricky. I then decided to make a cylindrical wooden container with a lid, and made a few sketches:

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As shown in the drawings, I wanted to make stackable ring layers that would form the walls of container, with interlocking protrusions and cavities. However I dropped that idea as the size and shape of the mill bit was another complex parameter in designing the joints. Finally I made digital drawings of flat rings that could be stacked and glued on top of each other to form a cylinder.

For some reason the MasterCAM always threw an error when I tried to apply contour operation to more than one objects, “The selected sub-chain does not touch the branch point.” I googled the error and most of the blogs mentioned some fixes in vectorworks which I did not understand. As a solution I tried making a similar drawing with .dwg extension in Adobe Illustrator, and it fixed the error. I was able to apply all the contour and pocket operations. (Using illustrator triggered another problem later!)


Three circles from the column on the left are the bottom (solid circle) and two lids (I planned to make two, just in case), with some engraving on the rim so that it would snap on the opening of cylinder. I set three operations:

  1. Cut the inside circles from the rings (Contour, counter-clockwise)
  2. Engrave rims of the lids (Pockets)
  3. Cut all circles and rings from outside (Contour, clockwise).

Next I prepared the techno router with a plank fixed to the bed. I required a 2’6″ x 1’6″, but found a slightly bigger sheet of plywood.


Next I set the origin and preprocessed the GCode file,

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…And then something weird happened on hitting fire. The router head further advanced in -Y direction and started cutting a circle:


I immediately hit the pause button, thanks to Ben’s instructions. The reason was I was working in bottom-right quadrant in the MasterCAM software, and I had completely forgotten to take care of it when I shifted from Vectorworks to Illustrator! This is evident from the blue MasterCAM image shown above. I thought of possible solutions andcould think of two:

  1. Go back to MasterCAM, move the drawing to top-right quadrant, export GCode and start all over again.
  2. Put the sheet in bottom-right quadrant. That is, set the Zero a couple feet away in +Y direction, and start the operation from beginning. The drawing would still be cut in bottom-right quadrant.

I decided to go ahead with the second option as it was quicker. I stopped the current file, moved the head approx 3 feet in +Y direction, and selected Zero All. This worked perfectly well, with drawing set in +X and -Y directions. Next part involved patience, vacuuming, and monitoring the router operation:

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The ply had a few underneath cavities and therefore a few rings were not perfect. Good I cut a few extra:


Next I applied glue and stacked the rings one by one on top of the bottom piece, and applied clamps to hold everything together for about an hour:



The cylinder looked beautiful and I sanded it evenly on the belt sander tool in the shop. This part involved careful handling as the cylinder was a bit slippery on the sander, because it was rolling like a wheel as soon as it touched the sander belt. The next trick was sanding it from inside. I used one of the circular pieces cut out from within the rings, glued sandpaper to its rim, and mounted it on drill machine. This custom-sander was really effective in finishing the inside surface of cylinder:



I used the same tool to sand the lid. The sanding made the lid a little smaller in dimension, and allowed it to snap perfectly on top of the cylinder:


Here’s how the final product looks:



The Othermill

Operating Othermill was a satisfying experience on many levels: simplicity of input file (just a flat SVG works!), user friendly design of the software, aesthetics of the machine, and finally the quality of the finished job. The 1/8″ flat mill bit ordered from Amazon seemed to be a quality product. I spent some time observing my classmate when they worked on their projects and that helped a lot while setting up my job.

The setup was much simpler and quicker than what I had anticipated. Steps were easy to follow and the only thing that went wrong was setting the Z axis. The drill bit descends gradually till it ‘touches’ (makes electric contact with) the metal bed, but a small piece of double-sided tape acted as an insulator and the bit kept descending further, making a harsh noise. Thankfully I managed to stop it as I was all set with the cursor hovering on the Cancel button.

Ben handed us all Derlin plastic sheets. The material has an appealing sculptural quality. The white material is translucent and I decided to make something that looks beautiful with lighting. I found this piece of pipe in the junk, and made drawings for Derlin caps that would fit on the opening of pipe.


It is great to see the software and the actual machine in action, sitting next to each other. The software displays the progress and simulation in real time.


Othermill is pretty precise when it comes to milling small and intricate parts:


I selected engraving for half the thickness of material. The final engraving and cutout looks like this:


The circles snap on the piece of pipe, and it looks wonderful with LED illuminating the pipe from inside.




This week we prototyped a physical object that can sit on a desk that allows a user to count up or down. The target audience is someone who wants to keep a numeric tally and have a physical reminder of their progress to display for themselves and others on their desk. A few examples discussed in the class were a guy keeping a count of how much coffee he drinks every week, and a PR employee eagerly counting the days until her next vacation. The exercise was fun and it involved a good thought process and applications of the latest readings.

I started with a mindmap, jotted down anything that came to my mind around this activity, and looked at all the wild possibilities that this product can offer:


I decided to take a step back and stick to counting up and down only, becasue

  1. Introducing too many smart features for a seemingly dumb activity, just because IoT can, might backfire. achieving usability by sacrificing delight could be a dangerous tradeoff.
  2. The user we are looking at are possibly surrounded by a huge number of gadgets already. Introducing another one should be a careful decision.
  3. The device should look inviting and feel satisfying when operated. I think this is the key to this exercise.

Much inspired by Dieter Ram’s design principles, I made this prototype:


The prototype offers a knob and a display. The knob affords clockwise and counterclockwise turning, which steps the count up and down respectively by 1. It is a knob with fixed snap-to points. This offers a tactile feedback when the count goes up or down.

The display is derived from cube clock that I recently saw and interacted with at MoMA design store.

moma cube clock

Assignment 1: Router

I worked on the assignment over the weekend, and it was fun to operate the router. I am comfortable with the workshop tools by now, still I was really excited about the router as I had never used it before.

The tools I used were a ruler, set squares, pencils and pens, tape, the router (with router bit, default round jig, circle cutting jig, jig pin), drill machine (with drill and screw driver bit), sander belt, and of course the vacuum cleaner. I started with fixing the wooden plank on the table and drawing on it.


Next I put on the circle cutting jig on the router, and figured out the settings that allow manipulating the depth of drill bit. Using drill machine with a screw driver bit was a quick way to remove the default round jig and replace it with the circle cutting jig.


Initially I had only a couple of millimeters of router bit popping out of the jig level, and I realized after the first run that the router is indeed much powerful. I then changed the depth of router bit to around a centimeter.

The jig pin didn’t fit in snugly in the center of the piece, so I applied some blue tape to make it thicker.


After carefully doing around four passes, the job looked like this:


The next part was a bit tricky. I removed the jig pin, mounted on the smaller jig, and used the edge of circle cutting jig as a guide to cut the straight line in the piece.


Lesson learned: After affixing the guide on the wooden plank, I should double check if it is still parallel to the line that I want to cut. The guide was not exactly parallel after taking in all the errors that arose when I drilled the screws to affix it to the plank below. The result was a slightly deviated (and disappointing) cut:


After fixing the error, I was able to get the line cut along exact course. Next I sanded it on the machine, and it improved appearance of the piece a lot.

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Here’s the final piece:

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Lessons learned:

1. The corners were tricky. To generalize it better, the ends are tricky while using a machine- the start and stop points need to be carefully thought of. I started cutting the arc from exact intersection of lines in the line drawing, but I stopped where the router bit touched the drawing line on the other end. So the error introduced is equal to the radius of the router bit.

2. Spending more time and efforts on the initial setup doesn’t cost, it indeed pays off.

3. Think of the number of hours it will take and multiply it by 3! The error handling, rectification, and most importantly post-completion cleanup takes considerable time. In summary it was a great experience to start the new semester with learning new tools.

Falling in love with an everyday object: Bose earphones

I don’t remember ever buying earphones or headphones as I am not really a big fan of any particular genre of music— until recently I used to listen to music only when I exercised. Earlier I had Apple EarPods with a nice, designed-in-california-by-apple case to protect them from usual wear and tear. The quality of sound was excellent, however, I could never use the EarPods as they always fell out when running. Winding the earphones up into the case was a also a nightmare— I remember watching a youtube video on how to put the EarPods back into the case when I tried putting them back the first time.


And one day my life changed! I received Bose earphones as a thanksgiving gift in November ’15, and this product has absolutely transformed the way I think of music and personal space. Interestingly, this product offers only the usual set of features that a typical set of earphones or headphones offer these days; but it does every single thing just perfectly well. The sound quality is exceptionally rich. There are physical button controls to play, pause, go to next/ last track, and change volume. The same housing also includes a mic. Also, there’s a carrying case that looks robust yet beautiful, and it lets you just wind up and put in the earphones without any strict rules or learning curve to it.

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I often listen to music while exercising and running on the track by Hudson waterfront in Newport with a magnificent backdrop of Manhattan skyline. The features that I thus love the most are the clamp and in-ear tips. the clamp takes care of the cable length so the earbuds don’t fall out when running. The soft tips just snap and stay and I can comfortably move around. It involves only little efforts to put on the earphones which might seem a task at first, but in practice I somehow find it satisfying when the curved protrusions ‘snap’ perfectly inside the pinna. What I find amazing is the fact that interaction isn’t limited to using hands alone (grip/ fingertips/ pinch etc.), but is also shaped by the significant roles played by other body parts (Ears in this example). After November 2015 I have exercised more regularly and merrily, and I find it really fascinating to see how a neatly designed product has influenced my behavior, rather than the behavior making me buy a product.