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Tim Booher

Wiring for 3HP 220V (for Laguna Tools 18|Bx)

I recently purchased a Laguna Tools 18|Bx 3HP 220V 18″ Bandsaw, specifically a MBAND18BX2203, and needed to wire a 220 Volt outlet. I’ve done a fair bit of electrical work (both low and high voltage), but I had a couple questions.

Just for the record, I enjoyed this video to make sure everything was setup correctly and this unboxing video was helpful. Also, here is the manual. The instructions weren’t great, but the wiring digram in the manual was helpful. YouTube and web forums are incredible for learning how to do new things like this. This article, Understanding 240V AC Power for Heavy-Duty Power Tools, was super helpful.

The 18BX2203 has a 12-amp 3 HP 220 volt 1 phase Leeson motor, with a 20 Amp recommended breaker. (Engines use more current on startup. Why not more Voltage?). 220V is a somewhat outdated nomenclature for the US system, but tools like this have adequate tolerance to take 240 without problems.

Laguna made this confusing since their website for the 18BX, differed from the manual. The website recommended a 20 amp breaker, while the manual recommend 15.

mismatch

The machine’s wiring diagram showed me a couple important things. First, I have no need for a neutral wire and the saw has a NEMA 6-15 plug.

wiring

The single phase motor will need at least 12-amps of continuous current at 240V (hot 120V + hot 120V) plus a ground. Here in the US, we have 240V single-phase residential, with a center tap. The center tap is called neutral. This is called “Split-phase” since you can grab the outer “phase” wires (hot-hot) or grab one phase and neutral for half the voltage.

This diagram cleared everything up for me:

Where I found myself confused was on the “single-phase”, if a “normal” outlet grabs one phase, and a neutral for half the voltage, wouldn’t a 240V setup have two phases? There actually is a 2-phase, but it’s weird as heck. It was basically two single-phase circuits set 90 degrees apart, and requires 4 wires instead of 3 but only carries about 14% more power for 33% more wires. Needless to say it wasn’t popular.

This diagram cleared it up for me. The amplitude of 120V on each leg adds to 240V at the same frequency. The current doesn’t add since the flow remains the same. A 240V-only piece of gear connects to two hot legs and a ground (no neutral), so if it pulls 20A, that 20A has to be going in one hot leg and out the other hot leg — there’s nowhere else for it to go! (In other words, it draws 20A, period — the legs do not “add together”.)

In setting up a 20-amp circuit, I had to make sure this worked with my setup. Per the table in the manual, I need at least 14 guage wire, so I went with 12 guage which I needed for the 20-amp breaker anyway.

wire thickness

How many wires?

I initially was going to use 12/2 wire, but I decided on schedule 40 conduit with Thermoplastic High Heat-resistant Nylon-coated THHN wire. I like this reference on wires.

I initially thought I would need to have 4 wires (a 12/3 wire), both a neutral and a ground in addition to two hot wires. After thinking about it a little bit, it made sense two use three wires total, since I was setting up a dedicated circuit and the ground and the neutral will have the same purpose. (The neutral is connected to the ground in the panel.)

What receptacle do I use?

The bandsaw came pre-wired with a 220V NEMA 6-15 3-pin plug. I used this page to make sure I used the correct outlet. One of the decisions I had to make was if I wanted to use a twist lock plug, but I didn’t consider the benefit worth the extra work to re-wire the saw.

For this setup, I needed a NEMA 6-20.

By the way, I learned that due to an exception in NEC, I’m allowed to plug 15A-plugged loads into either a 15A or 20A circuit. Further, a 20A circuit is allowed to have 15A sockets on it (as long as there are 2 or more sockets, e.g. the above NEMA 6-15 will suffice).

I decided on 20 Amp Commercial Grade Double-Pole Single Outlet, White which has two connections for hot and one ground wire and is a NEMA 6-20R, 2P, 3W.

Breaker

This is the most simple part. I need two 20 amp breakers that connect to different leads to get both parts of the split phase. This one will work.

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What you do is who you are

This book was a timely opportunity to understand the intersection of culture and action.

Ben Horowitz is the cofounder and general partner of Andreessen Horowitz, a Silicon Valley-based venture capital firm that invests in entrepreneurs building the next generation of leading technology companies. The firm’s investments include Airbnb, GitHub, Facebook, Pinterest, and Twitter. Previously, he was cofounder and CEO of Opsware, formerly Loudcloud, which was acquired by Hewlett-Packard for $1.6 billion in 2007. Horowitz writes about his experiences and insights from his career as a computer science student, software engineer, cofounder, CEO, and investor in a blog that is read by nearly 10 million people.

Here he writes about culture; specifically company culture. The book combines lessons both from history and from modern organizational research to give advice aimed at leaders that want to proactively design culture.

He starts the book with language similar to the Netflix culture deck:

Is culture dogs at work and yoga in the break room? No, those are perks. Is it your corporate values? No, those are aspirations? Is it the personality and the priorities of the CEO? That helps shape the culture, but is far from the thing itself.

I love Ben Horowitz’s brash style and direct advice, but the selection of non-traditional characters felt forced. It was hard for me to connect with characters more defined by their crimes than successes. While historical villians may present some lessons, I think the pool of case studies is large enough to include moral leaders, even if you force yourself to exclude white europeans, which is very Zeitgesity these days.

Studying gang dynamics for leadership lessons, has a Freakonimics like novelty to it, but I’m looking for impact over novelty.

Samuari and the difference between culture, values and virtues?

One case study I did enjoy was the focus on Samurai, specifially the focus on virtues over values. The samurai’s bushido code—"the way of the warrior"—lasted nearly 700 years and still infuses Japanese culture. It endured because it established clear requirements for behavior bounded by loyalty, respect, and sincerity and enforced them with severe consequences for misbehavior.

Bushido isn’t a set of principles, but a set of practices: it’s about actions, not beliefs. Other samurai virtues included honor, politeness, and sincerity: three complementary qualities that translate well to business.

He makes an important point that culture isn’t the same as values – values are more like aspirations, while culture has to mean something in practice. Virtues are what you do. Values are what you believe.

He hits a key point with his perspective on what matters.

Your own perspective on the culture is not that relevant. Your view or your executive team’s view of your culture is rarely what your employees experience…The relevant question is, what must employees do to survive and succeed in your organization? What behaviors get them included in, or excluded from, the power base? What gets them ahead?

Then, he emphasizes how important conveying context to a workforce is:

Above all else, employees want to know that they matter, they’re making a difference, there’s meaningful work to be done, and they’re moving the bigger picture forward. Without this, it’s impossible to get people to care.

If people don’t care, then it is just their own ability to succeed in the culture. If a culture can’t make quick decisions or has a void in leadership, it becomes defined by indifference.

Disagree and Committ

As a manager, the worst thing you can do is undermine decisions made above you. This creates cultural chaos, makes your team feel marginalized and powerless, and end result is apathy and attrition. If you disagree with those above you you need to leave before you start complaiing about them.

The problem is there is a lack of courage in most business leadership. Telling the truth isn’t natural. It requires courage. The easy thing to do is to tell someone what they want to hear.

The way you get to the place of being able to articulate a decision you might not agree with is by asking why. It’s your job to understand the reasoning behind a decision, otherwise you have failed your team.

You might not convince everyone you’re right. But everyone must feel heard and that you’ve acknowledged their concerns. This is the path towards disagreeing and committing.

Final Takeaways

Culture matters and leaders must be intentional. I also take his point that leadership lessons can come from non-traditional sources.

No matter what your culture is, your new hires should embody them: always hire people well suited to your culture. Second, make sure the virtues you choose are actionable. Like the samurai’s bushido code, they should be things you do, not just idealized beliefs. Third, while the virtues don’t have to be totally unique, they should at least distinguish your company from the competition.

This all requires trust. If your employees don’t trust both each other and you, a distinct culture won’t form. They should trust you so much that you can deliver bad news when necessary – for instance, when there will be layoffs – and still retain their respect. If they don’t, bad situations will have a habit of just getting worse and worse.

Ben Horowitz uses Abraham Lincoln’s Gettysburg Address to show how being direct can be so effective if done with context. With that speech, Lincoln managed to imbue the American Civil War with new meaning by explaining why so many soldiers had died at Gettysburg. He acknowledged the cost of the war, but also explained why he believed in its significance – a model for any CEO.

Bad news goes both ways, of course, and he makes the point that you should foster a culture in which you always know the worst of what’s going on. Every organization of significant size is home to lots and lots of problems: your job is to know about as many of them as possible. Your employees should therefore trust you enough that they can come forward with issues, and know that you’ll be positive and constructive about them when they do.

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Crossing the Chasm

Crossing the Chasm is a marketing book by Geoffrey A. Moore that explores the dynamics of marketing high tech products in early stage startups. While an older book, it continues to be read because the exploration and expansion of the diffusions of innovations model continues to have a significant and lasting impact on high tech entrepreneurship.

I would summarize the book into three main lessons.

  • The chasm is a gap between visionary early adopters and the pragmatic majority.
  • Crossing the chasm requires securing a specific niche as a beachhead first.
  • Position yourself as a market leader in your niche by making a strong claim.

Lesson 1: What is the Chasm?

Visionary early adopters start outside the space of the pragmatic majority. To change that, the book explores the technology adoption life cycle and concludes the states that new technology makes its way through the population in a bell curve distribution.

First, Innovators jump on the product, followed by early adopters, the early and late majority, to finally reach the laggards. Specifically, the chasm is the gap that lies between the early adopters and the early majority, when a product is very disruptive and requires behavioral changes.

This is due to differing motivations for buying a product. The visionary early adopters want huge changes and are willing to bet on them against the odds.

People in the early majority are much more pragmatic though. They don’t want big changes and huge innovations, but rather incremental improvements based on using proven products and solutions. But!, most arguments visionaries make to get the majority to buy aren’t appealing.

The majority wants to buy from established brands and companies, but without having the majority buy your product, you can’t become an established brand.

This dilemma is what Geoffrey Moore calls The Chasm and it’s something all high tech companies must overcome, if they ever want to see their product become successful and reach the majority of the population.

Lesson 2: How is the Chasm Crossed

This book claims that one can only cross the chasm by targeting a specific niche first. To make this happen, you start small.

This also resonated with me in reading Zero to One. Thiel insists that every startup should start small, because it’s easier to dominate a niche market than a larger, pre-existing one. Citing one of his earlier mistakes, Thiel recalls that PayPal initially let users send each other money via PalmPilots–a market that was, ultimately, too large and too spread out for them to control. PayPal then pivoted to work with eBay auctioneers instead, a smaller grouping of a few thousand "PowerSellers" who were easier to reach.

Here, Moore recommends to pick a very targeted and specific niche of customers inside the early majority to focus on and then expand into other niches later on until you cross the critical threshold.

Think of it as first securing a beachhead in an invasion, to take a stand and then build from there.

In order to convince your target segment you’re selling a holistic, well-supported product with good references and establish yourself as the market leader, you have to strictly sell to only your target group.

Don’t expand too early or sell to outsiders, just because you have the chance to. You’ll end up adjusting and customizing your product to death to make it fit for every individual purchase.

One of the best reasons for this, is the scarcity of time, people and money for early stage startups. It is critical to have forward motion.

Lesson 3: Make a strong (defensible) Claim

Position yourself as the market leader in your niche by making a strong claim.
Positioning is extremely important when it comes to customers making purchase decisions.

For example, when I mention Lamborghini, you immediately recall certain attributes in your head, like “expensive”, “luxurious”, “high-end”, “sportscars” and “rare”.

That’s great positioning in action.

Pragmatists want to know where you stand with respect to your competition (as they’re only interested in established brands), but you’re the high tech newbie, and there might not even be direct competition, so what can you do?

You define your competition yourself.

When you contrast yourself with a market alternative (the traditional way of doing things) and a product alternative (a competitor, who uses the same technology, but in a different industry), you can easily position yourself as the leader in the new, combined field.

For example, Dropbox could’ve positioned itself by saying: “For private PC users, who are sick of carrying files from one PC to the next via USB stick, we offer a hardware-free file syncing solution. Our service makes your files available on any device with an internet connection, just like YouTube does with video, but with any type of file you choose.”

These 2 sentences are all it takes to give you a powerful position – in fact, it shouldn’t take more than 2 sentences to make it clear to everyone in your target niche.

This claim will allow you to focus exactly on your initial niche and eventually take the majority of the market share there, so you can then expand and dominate the rest of the market as well.

Crossing The Chasm Review
I’ve heard the concept of Crossing The Chasm several times before, and I keep wondering whether it translates into other segments as well, where the products aren’t as high-tech.

If you want to learn more about it, Simon Sinek integrates it well into his TED talk. He says:

The problem is: How do you find the ones that get it before doing business versus the ones who don’t get it? So it’s this here, this little gap that you have to close, as Jeffrey Moore calls it, “Crossing the Chasm” — because, you see, the early majority will not try something until someone else has tried it first. And these guys, the innovators and the early adopters, they’re comfortable making those gut decisions. They’re more comfortable making those intuitive decisions that are driven by what they believe about the world and not just what product is available. These are the people who stood in line for six hours to buy an iPhone when they first came out, when you could have bought one off the shelf the next week. These are the people who spent 40,000 dollars on flat-screen TVs when they first came out, even though the technology was substandard. And, by the way, they didn’t do it because the technology was so great; they did it for themselves. It’s because they wanted to be first. People don’t buy what you do; they buy why you do it and what you do simply proves what you believe. In fact, people will do the things that prove what they believe. The reason that person bought the iPhone in the first six hours, stood in line for six hours, was because of what they believed about the world, and how they wanted everybody to see them: they were first. People don’t buy what you do; they buy why you do it.

Mr. Moore’s blueprint works, dozens of companies have proven it over the years – most recently Uber, who initially targeted the techy hipsters at the SXSW conference, video drones, who are becoming a standard tool for shooting video and of course Facebook, who collected college campus after college campus in his user base until everyone wanted to get an account.

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A mudroom

Our remodeled home included a mudroom and I was tasked to build the fancy hall trees that would store all our kids shoes, jackets and stuff. I am a member of the Wood Whisperer Guild and loved their design and construction techniques.

Design

I was inspired by designs like this.

Designing and building things parametrically in AutoDesk Fusion 360 has been a game changer for me, but this one was tricky since I wanted the start and end of the hall tree to include the width of the ply.

In order to make the width between the front facing the same, I had to do some math because the first and last boards were flush to the ends. The first and last cubby interior width is a and the middle widths is b. This is where a little math made the design a lot more clear and where the real cabinetry pros get confused. Hey! I’m an engineer not a carpenter without years of experience to just do this stuff.

$$ a = \frac{1}{4} (l – 6\, w) \; \text{and} \; b = \frac{1}{4} (l – 4 \,w) \; \text{and} \; k = \frac{l}{4} – \frac{3}{2}\,p$$

Or more generally:

$$b = \frac{l}{n} – w \; \text{and} \; a = \frac{l}{n} – \frac{3\,w}{2}$$

where n is the number of bins. We explored 4, 5, 6 to figure out what best used the space.

First, I needed to design five cubbies with equal width. I love building things, but use stock pieces and don’t have the time to glue up countertops or make faceframes. Because of this, I built this on top of an Ikea Karlby countertop (Article no: 703.352.12) which is super straight, low cost and beautiful. I played with the design to optimze the cutouts from 4×8 sheet of three quarter inch plywood. As an aside, I get my grade A or B plywood from Huston Lumber. The Home Depot stuff has a thin veneer and risks delaminating and is a lower version of grade C.

The final design resulted from lots of discussions in the space.

And used the following parameters. Calculating parameters made the design a lot easier to build.

Parameter Unit Value
room_length m 3.068 m
room_height m 2.5 m – 9 cm
ply mm 19 mm
countertop_height mm 37 mm
countertop_depth mm 650 mm
cabinet_width mm 575 mm
cubbies_length mm room_length – cabinet_width
cubby_depth mm 400 mm
base_cubby_depth mm 0.9 * countertop_depth
dado mm 6 mm
facing_width mm 1.5 in
facing_ply mm ply
a mm ( cubbies_length / n ) – ( 3 * facing_width ) / 2
b mm cubbies_length / n – facing_width
k mm ( 1 / n ) * ( cubbies_length – n * ply )
base_cubby_height m 18 in – countertop_height
top_cubby_height mm room_height – countertop_height – base_cubby_height
shelf_width mm k + dado * 2
cubby_height mm 1300 mm
len mm cubbies_length / n
n 5

I used the parametric features pretty extensively, basing everything off of fractions of the the total shelf length and room height.

The heart of fusion 360 is the sketch. By fixing the sketch and understanding the timeline, its possible to break down the design into a set of modular components that help you keep complex designs under control.

From there, I was able to use mapboards pro to get a cutlist, which I uploaded to cutlist optimizer to produce a fairly optimized design that efficently used three sheets.

Overall, fusion 360 estimates the total weight as 172 Kg, which is probably accurate with the long walnut countertop. I was planning on doing a stress analysis on the design, but I’m saving that for a future project.

Manufacture

After understanding my design, I primed everything with BIN primer that sprays on easily using my HVLP Harbor Freight gun. I use Harbor Freight guns for BIN because the cleanup is easy and I can frequently replace the gun. Since I sand the primer, the finish matters a lot less. For finish work, I use my FujiSpray MiniMite.

After priming, I used my Festool TS55 track saw to cut down the sheets. To make everything accurate, I made two jigs using 1/4 inch thick plywood and Starbond CA Glue. Reading up on ETHYL CYANOACRYLATE is recommended. It’s pretty cool.

This let me back super accurate cuts without needing to move big sheets of plywood on the table saw.

show the reader the cut pieces

After the pieces were cut, I went back to the model to update the dimensions I actually cut, which at my current skill level is around \(1 \pm \text{mm} \). In order to get everything consistent, I use the table saw to cut things down to equal dimensions and ensure everything is square.

Dimension Value (mm) My Value
Shelf Width (a) 482.1 481
Shelf Width (b) 491.6 492
Top Depth 400 399
Base Depth 585 582.5
Vertical Side Height 1952.8 1953
Base Height 420.2 419
Ply 19 18.67

Pocket Holes

drawing of kreg dimensions

I had to figure out how deep to cut the pocket hole with the 6mm dado. After building a drawing, it made sense to set the depth of the jig to \(\frac{5}{8}\).

For myself and others, I saved the chart I use here for depth and screw length selection.

I used stickers to make sure the screws from my pilot holes wouldn’t bump into each other.

I had a great helper to help me drill the pocket holes.


I measured the pocket hole screw to make sure I wouldn’t cut through the other side.

Assembly

I decided on which components I wanted to manufacture. Also during this time, I realized that I’m going to need a back to add strength to the overall design.

Components to manufacture

Finishing

painted bottom

I assembled the top cabinetry inside to make it easier to lift everything up.

mudroom

I love pocket hole joinery, but had to hide the screws on the top of the shelf and used Kreg Plugs. I had to cut down the plugs with a flush trim saw and used bondo putty to fill in. It’s great, you can’t see or feel that a hole was there.

I’ve always loved the finishing process and here I did several layers of sanding and putty. Mostly using two-part bondo and 320 grit sandpaper. I highly recommend the Festool ETS 150 with their dust collector. No dust and a super consistent finish.

After sanding 100 grit, then 180, I used Bondo multipurpose putty for extra strength. I also used clamps, a straight edge and bondo to ensure the edges were square.

The final product came out better than I expected. I still need to order and install the cabinet doors, but the final product is something I’m proud of.

mudroom

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Simple 4×8 workbench

In building out my workshop, I was tired of setting up sawhorses the garage and realized that I needed to better use the floor space of my shop. Setting up a 4×8 workbench is a right of passage for the aspiring maker. They are quick to make and super useful.

Most of them are pretty simple:

Some are just epic:

My main goal was to make an outfeed table and a common surface to cut with my festool track saw. I also wanted a cabinet makers vice and a holddown system based on t-tracks or MFT hardware.

I went with t-tracks and these clamps and these tracks. These have been incredible and I use them with nearly every project. Initially, I bought these intersection kits, but found I could use my miter saw with the right blade to cut all the intersections.

I was initially excited about making the top out of Valchromat, but the pain of sourcing that in a covid19 enviornment was too much of a stretch and I settled on Home Depot MDF for the top. To be able to swap out the top, I glued everything but the top which I used about 10 pocket screws to attach.

I was inspired by April Wilkerson to build the workbench completely out of plywood with pocket screw joinery and I’m really glad I did. I needed the workbench to be mobile and incorporated a Workbench Caster kit that retracts to give me the benefit of firmly planting the workbench to the ground. Unlike other designs, I planned for the bottom base of plywood to directly touch the ground, since I didn’t see a benefit to having space underneath the table and I wanted 100% rock solid surface.

Before building the design I came up with the following requirements:

  • Important storage needs were for my spare wood, my growing collection of jigs and saw blades and framing supplies.
  • Storage for:
    • store foam for framing (30X40 acid free mat boards)
    • saw blades and push sticks
    • Festool tracks (The rail is 183mm wide, plus additional 2-3mm plastic lip)
    • My large and small T-squares
    • All my small parts bins
    • Spare wood
  • The surface needed to be covered with t-tracks for easy workpiece clamping or MFT (pattern of holes 20 mm in diameter, and are spaced 96 mm center to center) (I chose t-tracks)

The sole complication of my design was incorporating my table saw that wasn’t meant to be surrounded by plywood. The goal of the design was to save a lot of space and provide me an outfeed table, but getting the top flush and level was challenging. (I had to use my car jack and shims.) The most difficult part was cutting out the voids for the guide rails and the lever for the riving knife. This was really hard because both of them intersected the tabletop so I had to use a router and a chisel to carve space out of the tabletop. I was inspired from others who built similar designs, but I thought I could signifcantly improve on them.

To get me thinking through my design, I did a quick design in Sketchup.

Once it was time to get serious, I used Fusion 360 to build a refined design. Fusion 360 (free for hobby folks) uses parametric modeling which gives me the ability to modify the model as I take measurements. One of the important impacts of parametric design is the ability to keep tweaking the design as I optimize cutting out of the plywood. Also, I can start designing without measurements, and in this case I did most of the design in the car on the way home from the beach.

Once home, I was able to get some key measurements:

Fusion 360 is a serious modeling solution and I added more detail, like the ability for the fence to go to the left of the saw.

For all joinery, I used Kreg pocket screws with 2.5 inch cabinet screws. I tend to like McFeely\’s and square drive, but Home Depot is so much easier, and they store GRK Fasteners with star drive heads that don\’t strip.

One of the best features of Fusion 360 is the Map Boards Pro extension that allows to generate a cut-list and creates all the relevant bodies as a flat-pack.

This gets me a rough feel of all the boards I need to cut, then I like to use cutlist optimizer which is easy because I just upload the cutlist exported from MapBoards pro.

Mistake

The casters were perfect and rated for 880 lbs each, but the bottom screws couldn’t hold the weight and ripped out of the workbench. More engineering was needed!

I designed a flat plate of aluminum (1/4 inch thick) in which I would tap M5 threads (5mm hole) to bolt the casters into. I made six other holes 5.5mm in diameter for longer m5 bolts that would allow me to bolt them on from the back.

I purchased four Aluminum Flat Bar, 1/4″ x 4″, 6061 General-Purpose Plate, T6511 Mill Stock, from Remington Industries and used my Shapeoko CNC to cut the first 4 mm but I finished them off with special drill bits on my drill press so I could ensure highly accurate hole diameters. To cut the aluminum on the CNC, I used Kodiak Cutting Tools KCT166406 1/8 End Mill. I was cutting a 5 mm holes using 10k rpm with a feed rate of 500 mm/min and plunge of 120 mm/min for a boring operation in fusion 360 with a pitch of 0.5 mm.

Working with metal is just awesome, for one it helps me claim I’m an engineer and maker more than a woodworker only.

For reference, I was able to use
this site for hole sizes and this tap and die set.

Mistake #2

In tapping the threads for the M5 bolts, I used the fine pitch tap (0.75 mm pitch) not the 1mm pitch I should have. This was a problem since you can’t easily find fine threaded bolts. Thank you McMaster Carr for saving me out of this one.

Finished Product

Seriously, this was a super fun project that came together exactly as planned. The t-tracks and clamps are my favorite feature, but I love the huge storage for framing supplies. (I love making custom canvases and frames.)

The metal supports for the casters at the bottom worked out really well.

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I need a clamp

So I need a clamp, specifically a corner clamp jig.

Google finds this:

And I was inspired by this fireball tool mega square but they are $190.00 for a 12 inch. Yes, made of cast iron, but I was curious if I could make this myself. For one, a MDF clamp would be just as straight, but a lot lighter.

It did take 45 minutes to draw in Adobe Illustrator. This was a bit hard because I wanted all the lines to be exact and symmetric. I used the measure tool to verify all the dimensions and locked into their grid to make sure all the angles were correct. The pathfinder tool was super helpful in making the complex shapes.

I exported this as an SVG and set up the toolpaths in Carbide Create and selected a #201 1/4 inch endmill that allowed me to use a 0.3 inch single pass cutting depth at 18000 rpm and 80 inch/min speed. Details here and full tooling support.

My toolpath simulation:

I was blown away with how fast the MDF cut (3/4 inch in three passes) and it took about 6 minutes to make the whole piece.

The final product exceeded my expectations, super clean lines and I tested this on several boxes. It really did make clamping corners easy.

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Garage Workbench

With all the isolation ahead with Covid19, I wanted to pick up my long neglected hobby of building things.

Initial Design

I recently purchased the shapeoko 3 XXL CNC and needed a workbench in my garage to support it.

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Requirements:

  • Super strong and sturdy
  • Big enough for Shapeoko (45”W x 40-1/2”L x 16”H)
  • Fast to build
  • Enable easy cleanup and dust collection
  • Very level surface

I came up with this design while riding with my family to go hiking. While it would be easier to just use butt joints with pocket screws, I wanted a more integrated and stronger design.


In order to organize everything, I thought through the cuts I needed to make and divided each set of boards into colors.

I cut the pink boards first, followed by the green and finished with the blue (top) frame last. SketchUp’s outliner feature was super nice for automating all the labeling.

The most complicated cuts were the top frame.

This was made a bit easier by setting up the right Dado blades, which made cutting these boards fun.

An essential part of building all of this was constantly adjusting the dimensions as the boards were not straight, the floor was not level and the wall was also not true. Critical to getting everything tight was understanding which dimensions were driving the design. For example, the orange pieces set the height and the pink pieces set the length.

Building

Since I’m still new to this, I had to think through the order of my cuts. It was super helpful to have printed plans to keep track of all the cuts.

annotated plan

First, I planed all my 2x4s to get nice flat edges.

planed boards

I used the dado blades on my table saw to notch out the board widths and assembled on the floor.

The most complicated pieces were the left and right framing pieces.

It was super cool when everything fit together, but I had to adjust the tabletop dimensions once I put the frame together. I turned my clamps into spreaders to make sure the top was level before cutting.

Second Project, Tool organizer

Second, we built a tool organizer.

The plans are below.

This came together pretty well.

Completed Project

completed project

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Kitchen Shelving

As we renovate our house, we are living in a much smaller place with a really small kitchen. When we got a Linea Mini and a Eureka Zenith 65E High Speed Espresso Grinder for Christmas, we needed a good spot and I designed a set of shelves to fit in our kitchen alcove and dramatically improve the space. This post shares my design process and the tools I use to save time and money.

Right now, our kitchen looks like this. Yes, my daughter is wearing an I ❤️code github shirt.

And we want to have something like this

First, to generate the design, I used Sketchup which is super fast and a good way to get a feel for what is possible. Critical to getting fast drawings in Sketchup is a good laser measuring device, I love this one.

From my initial sketches and discussions with Chrissy, I picked a design that gave us shelf space and didn’t interfere with the walls of our rental.

My initial design looked like this:

Which I felt gave us the maximum storage and shelf space. Notice how my sketchup drawings lack engineering detail. For engineering design, I turn to Fusion 360 from AutoDesk.

Fusion 360 is simply amazing software that enables fully parameterized design. This allowed me to start with rough measurements and to keep refining the design by changing parameters. My daughter and I measured the following parameters:

This allowed me to iterate with my wife several times until I ended up with a design we liked.

Notice the increased detail. I even modeled the right properties of the wood so I could get weight and cost estimates, which all comes out of the box with Fusion 360. After the final design was complete, I was then able to model the detail, such as the dado cuts and model the structrual support. So if you look closely at the design, you will see that I can get the exact dimensions.

This enabled me to build a cut list, which showed me that I would have to use 5 4×8 sheets of plywood to complete the design. I first did this by using the joints feature of Fusion 360 to see that I had parts that wouldn’t fit.

I used google slides to play around with different sizes on a screenshot, and modified the design to fit on three sheets. This is where the parameterized design really helps.

Then I had to add structural detail.

In order to make my cuts accurately and minimize waste and to finalize my cuts, used an optimization heuristic check out the math. In terms of computational complexity, the 2d cutting stock problem is an NP-hard problem reducible to the knapsack problem. The problem can be formulated as an integer linear programming problem. I’ve studied this problem a bit, and I find it interesting because of how degenerate the solution space is: multiple solutions with the same amount of waste are possible. This degeneracy arises because it is possible to move items around, creating new patterns, without affecting the amount of waste. However, some have claimed optimality in some circumstances. To get optimality you have to do things like enumerate the possible cutting patterns, and solve the associated integer program by a combination of cutting planes and branch and bound.

You don’t have to know this. It is all implemented at cutlistoptimizer.com. I had to do some units manipulation and rounded up the nearest 1/16th which is my wordworking tolerance without a cabinet saw. FYI, this formula helped: ROUNDUP((A2*12)*16,0)/16.

Cutlist optimizer produced a nice set of cuts.

# Panel Cut Dim
1 48×96 y=13″ 96″
2 13×96 y=66.06″ 13″
3 34.87×96 y=29.75″ 96″
4 29.75×96 y=13″ 29.75″
5 13×29.81 y=12.13″ 13″
6 13×17.55 y=12.13″ 13″
7 29.75×82.87 y=81.13″ 29.75″
8 29.75×81.13 y=13″ 81.13″
9 16.62×81.13 y=13″ 81.13″
1 48×96 y=66.06″ 48″
2 48×66.06 y=13″ 66.06″
3 34.87×66.06 y=13″ 66.06″
4 21.74×66.06 y=13″ 66.06″
5 48×29.81 y=36.31″ 29.81″
6 36.31×29.81 y=29″ 36.31″
1 48×96 y=36.38″ 96″
2 36.38×96 y=74.63″ 36.38″

I also like that it planned my cuts with a 17 cut optimized design. Overall for three sheets, I was able to use 72% of the area with a total cut length of 897.44". Now, I’m ready to build and hopefully end up with something like this:

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