Blog Posts

terça-feira, 24 de fevereiro de 2015

Aprendam Grasshopper, Vendam no Facebook, que a Paypal oferece reembolso, façam Zappers, e uma Impressora 3D GRANDE!

Iniciativa do nosso amigo Victor Sarderberg, eis um Curso de Grasshopper em Português, para aprenderem como é, com quem sabe, sobre a Modelagem Paramétrica, no Programa 3D Rhinoceros.

De nota, também o Site, o LearnCafe, onde poderão também ensinar o que sabem, ora aí está uma rica ideia, se ao menos uns Torneiros Mecânicos que eu conheço pudessem fazer um curso,  entre tantas outras coisas boas a aprender...

Grasshopper - Modelagem Paramétrica e Computacional 

O curso tem por objetivo introduzir e aperfeiçoar o conhecimento na ferramenta de modelagem Rhinoceros e seu plug-in de modelagem paramétrica Grasshopper. Além do conhecimento técnico transmitido, é importante salientar mudanças na estratégia projetual e de lógica. O curso visa, também, orientações de como produzir seus projetos a partir do novo paradigma da fabricação digital. 

Atenção, malta, podem vender por 14 dias o que quizerem, no Facebook, por isso, aproveitem esta oportunidade para fazer uns cobres, vendendo. 

To the men and women with the entrepreneurial spirits
Take advantage of the network you’ve already built and start selling things on Facebook right through your existing business page. Give your fans an opportunity to view, purchase and share any product that you make available in your Facebook store.
Using the Shopify Facebook Store app, a customizable tab is automatically placed on your Facebook business page, allowing your fans to buy your products right then and there! It’s never been easier to monetize your social media presence.

...E como não quero que vos falte nada, ficam já a saber que a PayPal oferece as Despesas de devolução, para vos facilitar a Venda ainda mais!
Mas é que é só facilidades! 

Menos uma preocupação. 

Reembolso dos seus custos com devoluções. 

Agora, ao comprar online com PayPal poderá obter o reembolso* dos seus custos com devoluções de compras, caso mude de ideias e mesmo que tenha comprado fora de Portugal. Para beneficiar deste novo serviço já na sua próxima compra, ative-o já grátis com um só clique.

Vender, o quê?
Olhem, por exemplo, este bacano fez uma Pistola Laser do Jogo de Computador, League of Legends, e está a vender o que faz!
Isto é que é Categoria.

Hobbyist creates working League of Legends zapper pistol

Ben Coxworth

Laser weapons hobbyist Patrick Priebe is no stranger to building functioning versions of guns from video games. Recently, he received a number of requests to create something from the game League of Legends. The result, the Jinx character's zapper pistol, could certainly be described as "electrifying."
The zapper features a rosewood grip, white and blue LEDs in the barrel, and blue LEDs farther back. Other parts are made from gold-painted aluminum, and gold ol' steampunky brass.
Pulling its trigger activates a balloon-popping/hole-burning 1.6-watt blue laser, along with a "lightning-in-a-jar"-type feature in the rear. The latter is made from a flash tube of the type used in studio photo flashes, filled with xenon gas. When voltage is applied, the arcing electrical "streamers" are the result.

...E, acho que isto foi Dica de Eddy de Ridder, como os Engenhocas têem tantas hipóteses de ganhar o TotoLoto, como qualquer um, podemos sonhar com esta Fresa, e Impressora 3D, assim mais para o...
Teriam de nos arrancar à força da Oficina, com um Bichinho destes, lá...

Artis develops giant KUKA robot, a 100 cubic meter CNC machine & 3D printer in one 


You might not think about it when toying around with a conveniently-sized desktop FDM printer at home, but 3D printers come in all shapes, sizes and price ranges. But while we come across large and unusual 3D printers all the time, even we were very amazed by the KUKA Quantec Ultra machine, developed by the Berlin-based construction and engineering company Artis Engineering. While exceptionally large, it’s especially amazing for its dual nature: it's a CNC milling machine and 3D printer in one.
Artis Engineering is an interesting company that really illustrates how continuous innovation is key to success. Established in 1994 as a producer of classic cabinetry, they have since grown to a company employing 30 people and specialized in creation unique shapes, cabinets and setups for museums, art exhibitionsm medical practices, trade fair stands and so on.

segunda-feira, 23 de fevereiro de 2015

Injecção de Plástico, da Impressora! E forjar uma Faca, Micarta, e o CNC Arduino

No capítulo das ideias que todos goataríamos de ter, eis como fazer peças, com a Impressora 3D, ou pequenas, ou demasiado detalhadas, ou ambas as coisas...
Por exemplo, imprimam em 3D uma peça, e aperfeiçõem do Detalhes;
Usem a peça para fazerem um Molde em Silicone;
Injectem lá o Plástico, da Makerbot...
Já está.

Turn Your 3D Printer Into an Injection Molder
Matt Stultz

One of the issues with using FDM/FFF 3D printers is the ability to print small objects. The extrusion widths of the deposited plastic are just too large to capture the fine details in a miniature print. 
Molds, on the other hand, can capture every detail of an item they are trying to create. The professional world uses injection molding when they want to create small detailed parts. 
Now, Instructables user BFK (Bruce Kinsey) has created a great guide on how you can do the same with the help of your 3D printer. 

Eis um método facílimo de forjar em Metal, neste caso, uma Lâmina de Faca, mas pode ser qualquer outro objecto...
Com Ossos de Choco!
Chocante. LOL
...Chocante, de tão boa ideia que é!

Cast a blade

When I was a kid my father used to make jewelry. I watched him make
amazing things and I could always count on him knowing how to do something that would help me with my projects.
One day I asked him to make me a fish necklace. I was surfing at the time and everyone was wearing something interesting. Dad pulled out some cuttlefish bone and asked me to draw what I wanted on it. I drew a fish and then watched him turn my picture into a 3d object. He used a fine tipped oxy acetylene torch to heat up a bar of silver and drop forge it into a mould.
The result was so beautiful! The fish had a timber-looking grain running throughout it and it was timeless because of the old-school feel. I never forgot that day and have always wanted to try it again. Well here we are! Time to forge a letter opener with a timeless feel. This knife may not be practical as a bush-bashing, hair-whittling kitchen knife, but as a work of art it will certainly have people asking how you created it. I hope you all enjoy and get the opportunity to try this at your own home.

Parece um prato Japonês, mas não, é uma técnica do século passado, que consiste, muito simplesmente, em embeber Tecido com uma Resiña, prensá-lo, e produz-se assim uma Placa.
Sim, como a Fibra de Vidro, mas esta versão é mais para o Artístico, devido aos efeitos da Maquinação em camadas de Tecido de cores diferentes.
Mas poderá também servir para N outros fins!

How to make homemade micarta

Here is a short video showing how I make my homemade micarta that I use in knife handles quite often. One tip I didn't mention in the video was to use superglue to finsih the micarta. Sand it to 320 grit, rub it really well with a green scotchbrite pad (hot tip- those with dremels, chuck the scotch brite in the dremel for fast polishing). coat the handle with 5-6 coats of thin superglue, sand it at least to 320, use green then white scotchbrite (in the dremel for speed). that should give you a nice finish. attached are some examples of my homemade micarta. First two pics are a girly knife handled with pink and purple denim micarta. Third and fourth is a kitchen knife I made with the micarta in the vid, and the fifth is some with bright orange cloth. sixth is blue jean and pink jean (this was my sisters christmas present) . 

E acabamos, por hoje, com mais este Projecto para fazerem a vossa própria Máquina CNC, com o Arduino, e pouco mais:

Arduino CNC

Hi, this is my first instructable and I hope to do more.
This project was for 'Creative Electronics', a Beng Electronics Engineering 4th year module at the University of Málaga, School of Telecommunications.
It's a cnc using Arduino UNO R3 , GCode Sender and GRBL. The cnc is made of wood thanks to the help of my father. It has taken us many hours to do the mechanical part however the electronic part is faster to do, but is very gratifying. I based my project on these videos and I have received much support from the author of the first video.

sexta-feira, 20 de fevereiro de 2015

Concretizes, uma Crowd-Funding Brasileira, façam os vossos próprios Brinquedos, Treshold, e Azeite

Para mudar o Brasil, pela positiva, podem contar com estes amigos, que criaram um Crowd Funding muito especial, a Concretizes!
Louvável Iniciativa que aplaudo, por estar em sintonia com toda a Filosofia deste meu Blogue:
Melhorar, Inovando! 
Gosto, sobretudo, do Desengavetador de Projectos...

Quem somos 

Um sonho de família que surgiu de nossa longínqua intenção de ajudar as pessoas a concretizarem projetos em diversas áreas. Somos interessados em cultura geral, inovação, empreendedorismo, causas e negócios sociais, games, artes, esportes e todas as demais áreas!
Aqui, o seu projeto vira realidade e a realidade transforma o Brasil!
Pensando em tudo isso, decidimos criar a, que é uma plataforma de Financiamento Coletivo (crowdfunding) e um Desengavetador de Projetos!
O Financiamento Coletivo (crowdfunding) é muito famoso nos Estados Unidos e na Europa. Aqui no Brasil, através de nosso site, pessoas que se sentem atraídas por um projeto, tem a oportunidade de ajudar financeiramente o Criador dele a realizá-lo. O projeto pode ser dos mais variados tipos, por exemplo, gravação de um cd, lançamento de um livro, realização de palestras, eventos, criação de documentário, de novo produto, invenções, empresas e negócios sociais, auxílio a um artista, ação social, ONG, escola, atletas, comunidade, encontro de amigos, confraternização, show, etc.

Eis uma ideia nascida da lembrança de uma Mãe que apoiou um Filho que ela achou criativo, e é simplesmente, como fazer as Crianças criarem os seus próprios Brinquedos:

Build Your Own Toys with ThinkFun’s Maker Studo
Kathy Ceceri
As I mentioned yesterday, the big theme of this year’s Toy Fair in New York is “joining the maker movement.” But to qualify as a genuine maker toy, a plaything should meet some basic criteria. One new series of kits that fits my definition of a maker toy is the Maker Studio Construction Sets from ThinkFun. The building sets are a departure for ThinkFun, which is better known for their logic games like Robot Turtles and Rush Hour, but completely in keeping with their theme of brain-building and hands-on fun. Designed by engineers David Yakos and Parker Thomas, the three Maker Studio sets — there are Gears, Propellers, and Winches — include struts, connectors, and moveable parts like wheels. It’s up the user to find a suitable body, and the sets encourage kids to look for recycled containers and materials to build out their projects, like the mac-and-cheese box racecar chassis.


Regulem uma Voltagem determinada, e quando um circuito tiver uma Voltagem maior que ela, esta simpática Gigajoga da Littlebits acciona luzes, motores, etc.
Mais uma boa ideia da LittleBits:
Think of the threshold as a toll booth for signal passing through your circuit. The threshold compares the incoming voltage coming from the bit snapped before it against the voltage amount you’ve set by the threshold knob. If the incoming voltage value is greater than the selected voltage, the threshold will allow the signal to pass and activate any bits (lights, motors, etc…) following it. If not, then nothing will be activated. Use it to make any sensor module into a trigger module!


 ...E o que é uma óptima notícia, e bem que precisamos de boas notícias, descobriu-se agora, como é que um ingrdiente do Azeite Extra-Virgem, que Portugal produz, do melhor que há, mata as células Cancerosas!
O oleocanthal, é esse o nome do tal Ingrediente, vai ao compartimento, nas células, que contém os desperdícios,e fura-o, desencadeando a auto-destruição das Células cancerosas, por isso, é de esperar mais esta Arma no Arsenal da luta contra o Cancro...

Olive oil ingredient leads cancer cells to their death
Nick Lavars 

An ingredient found in extra-virgin olive oil called oleocanthal has been known as a compound capable of killing a variety of human cancer cells, but how this process actually played out was not understood. Now, a team of researchers has uncovered not only how oleocanthal destroys cancer cells, but that it is able to do so while leaving healthy cells unharmed.
Paul Breslin, a professor of nutritional sciences at Rutgers University, had thought that oleocanthal killed the cancer cells by targeting a key protein in cancer cells that triggers apoptosis, a process that sees dangerous or damaged cells self-destruct by upsetting the balance of ions in the cell membranes. In investigating this theory, he teamed up with David Foster and Onica LeGendre, two cancer biologists from New York City's Hunter College to more closely examine the process.

quinta-feira, 19 de fevereiro de 2015

5000 Dólares para o vosso Protótipo!!! E OpenPi, Ponoko, agora, Corta Metal, 10 usos para o VLC, Uma Oficina num só móvel, e um Fogareiro.portátil

Querem 5000 Dólares para construír a vossa Engenhoca, ou o vosso Protótipo?
Concorram, DEPOIS de patentearem a Ideia, a este Concurso da Make, e habilitam-se a ter o Protótipo dos vosso sonhos...
DEPOIS de patentearem a Ideia!

Pitch Your Prototype… And Win $5,000
Jon Christian

Want a chance to win $5,000 and be featured at MakerCon New York this September? If so, consider entering the Pitch Your Prototype contest, a collaboration between Make: and Cornell University with the goal of digging up promising prototypes from the Maker community. Maybe you’ve been working on a wearable, or wrestling with a Raspberry Pi. Regardless, don’t be afraid to put yourself out there by entering—contestants in previous Make: contests have included an aerial film platform, plushies modeled on video game characters and an outrageous four-wheeled bicycle made from recycled materials.

Maquineta fantástica, dica do nosso amigo Fernando Mattoso Lemos, eis uma Ferramenta para os Inventores, que vos permite juntar Controle programável ao que precisem, como queiram, e au um preço bacano!
É bom, ou não?
Até a Microsoft está usando...

Open source design lowers cost by 2/3rds of building Raspberry Pi Compute 1&2 powered cool stuff.
Update : We are adding to the design support for Bluetooth Low Energy
Update : We are adding an IR receiver to OpenPi
Update : Check out OEM and EmonCMS running on OpenPi read more
Update : Microsoft are using OpenPi on Tech Days read more

Wouldn’t it be great to build hardware at the speed or cost of software?
OpenPi is an open source project, and a neat alternative to the Rasberry Pi Compute development kit. The holistic approach for non-embedded engineers, guides people who love to write software, through the problematic stages of getting small scale products to market. On offer are reference PCB’s, a customisable ABS case, open-source design files and collaborative design support. When it’s as easy to get up and running as a games console, and affordable enough for cottage industry inventors to profit from, OpenPi is forging a new way of bringing cool ideas to the masses.

Pois é, podem mandar agora os vossos desenhos para a Ponoko, e recebem em casa as peças cortadas, em Aço, Cobre, ou Bronze!  
Por isso, inscrevam-se e mandem vir as vossas engenhocas 

New! Streamlined Support for Photochemical Machining

Making with metal just got a whole lot easier.

We are thrilled to announce new streamlined support for Photochemical Machining. Previously, if you wanted to create something using Brass, Copper or Stainless Steel, you had to take an extra step to email us the extra details of your order.
Now you can upload PCM design files directly to your Personal Factory account. In addition, you can now upload and get a quote for metal parts along with Laser Cut & 3D Printed designs at the same time, all in one order.
How to make with Photochemical Machining (PCM):
  1. Prepare and save your vector design as a PDF using our Metal Machining Starter Kits.
  2. Upload your PDF to your Personal Factory account.
  3. Select your choice of metal materials and proceed to checkout as usual.
That’s it! You’re now on your way to receiving some awesome metal goodies in your mailbox. Please note: The design requirements for PCM are slightly different from laser cutting with other materials. You’ll want to be sure to read through our design guides before uploading your designs.

Achado através do Stumbleupon, o Site HowToGeek vem-nos ensinar como fazer de tudo um pouco, em Vídeo, com o programa Grátis VLC Media Player!

10 Useful Features Hidden in VLC, The Swiss Army Knife of Media Players

There’s a good chance you already use the VLC media player. But VLC isn’t just a media player — it’s a complete Swiss Army Knife for digital videos and music, filled with useful and fun features you haven’t found yet.
If you’re just using VLC to play back local media files, you’re only using a tiny fraction of VLC’s capabilities. There’s so much more you can do with VLC, whether you’re using it on Windows, Mac, or Linux.

E só porque sim, cá vão de embute, dois Instructables impecáveis...
Este, como fazerem uma Oficina num Móvelzinho articulado e cheio de truques, com rodas e tudo!

Complete workshop in a shelf

Most Instructables projects require you to have some basic tools and a workshop available - unfortunately, most people do not have the space for these bare essentials available. Just like me.
My girlfriend and I live in a moderate sized apartment for some years now. We have got a spare room that offers sufficient room for our hobbies. Now we expect a baby and this room is assigned to it. As a consequence, I have to move all my tools in a tiny compartment of an IKEA shelf and have to find a new workspace too.
I approached this problem, by building a compact yet solid frame made of low-cost aluminum extrusions. It offers some very handy features:
  • storage space and organization for my tools
  • frame acts as a multi-purpose workbench. It offers:
    • a drill press
    • a router table
    • a bench vise
  • Concept is very flexible and may find further extensions.
Everything is designed to fit the size of the compartment. Total costs of this project are about 150 EUR.

Faz frio que se farta, pelo menos em Portugal, mas eis como terem, e até fazerem, a vossa comida quentinha para onde quer que
forem, com quase lenha nenhuma!
E facílimo de se fazer:

UPDATE! Backpacking Gasifier Stove

Hello, this is Quark- and I am here to show you how to make your own TLUD (Top Level Updraft gasifier stove), and you can look them up at They are essentially a stove that burns the fuel not once, but twice. The base thermos holes allow air into the fuel, while the top holes allow preheated air down into the stove to basically burn the fires smoke. I recently learned about the design while looking up specification for the popular Biolite Campstove, a design which I sought to make. Only then did I learn that it was a gasifier, and the rest is history. They are often used in third world countries, due to the fact that they are incredibly cheap to manufacture and are 10x more efficient than just a plain fire. Because of the double-walled construction, it is easy to use a simple food thermos to make one of these beauties. Enough talking, Onward!

Publicidade, eis um jogo bacana:

Game of War - Fire Age - iOS
Join the ULTIMATE battle for domination of the Kingdom in Game of War – Fire Age! PLAY FOR FREE in the most addicting, interactive Action Strategy MMO GAME!

segunda-feira, 16 de fevereiro de 2015

Engenhocas ajudam o Mundo! E Thermite, a Dinamite dos Pobres, e o Cu-Box-i4 Pro

Mais de 50 Campos em que os Inventores, Fabbers, e demais Engenhocas podem ajudar a resolver problemas prementes deste Mundo?

50+ Global Issues Makers Can Solve
Michelle "Binka" Hlubinka 

Lawrence Berkeley National Lab—along with USAID’s Global Development Lab, The Lemelson Foundation, The Schmidt Family Foundation, Dalberg Global Development Advisors, The Good Company and OMG—has put together a list of challenges primed for Makers to solve. They call these “Top 50 Game-Changing Technologies for Defeating Global Poverty.” These are summarized in a 20-page list, and then fully explored in the full 600-page report. They shared this list “because the problems we all seek to address require urgent action,” and they invite the problem-solvers of the world (you, dear readers!) to “begin the conversation.”

Cá vai uma contribuíção da minha parte, desde há muito que se partem Rochas com fogo, e depois àgua, ou com cunhas em madeira, que se encharcam, mas depois, veio a Dinamite.
Mas em regiões onde não haja Dinamite, para Obras necessárias, ou até para destruír Minas já detectadas, (mas feito com um rastilho longo), que tal usar Ferrugem em pó, alumínio em pó, e gesso para o mesmo efeito?

Ou seja... Thermite! 

E de forma a ser moldado em qualque forma sólida.  

Atenção, no entanto, isto pode não ser tão perigoso quanto a Dinamite, mas é, à mesma, para ser manuseado por gente séria, e responsável...

Cast Thermite
There are plenty of Instructables and other how-to's on making Thermite, the incendiary mixture that can not only raise, but also burn, eyebrows. (The concept for this Instructable came from 'the Anarchists Cookbook', and since it doesn't give many's how I do it.) Now, there's nothing wrong with powdered forms of Thermite, that's how I got started a few years back, but sometimes you just want something rock solid that burns nice and bright/hot.

That's where Cast Thermite comes in. And the best part is, If you have some thermite on hand already, it's pretty easy to make! If you don't, never fear, for I will be starting at the beginning with nothing but the raw materials.

E mais um Computador para competir e/ou ser conjugado com o Arduino e o RaspberryPy, este Cubo, o Cu-Box-i4 Pro vem com muita coisa mais, e a um preço bastante razoàvel:

Box-i4Pro, the small cheap computer in a cube  
Lara Lopes
You’re probably pretty familiar with the success of the likes of the Rasberry Pi and Arduino boards, tiny little computers packed onto a single bare board lapped up by digital enthusiasts and hobbyists. Well, the CuBox-i4Pro is not all that different except it’s packed nicely into a case and this small cheap computer in a cube not only packs quite a bit of power it comes at an incredibly reasonable price.
It’s created by Israeli startup SolidRun who created the first Cubox back in 2013 and we’re now on version i4Pro. The cube measures just 2.17” (55 mm) in width, length and height and packs Bluetooth and Wifi capability. The system comes with Android pre-loaded on a 4GB micro SD card and can also run Debian Linux.

quinta-feira, 12 de fevereiro de 2015

Reparar rodas dentadas? E 2 pró Raspi, um Forno Português, e um Centralizador

Este Instructable, pela sua simplicidade e eficiência, é uma Obra-Prima de Reparação Engenhocas... 
Olhem que usar os dentes das outras Rodas dentadas, como Molde para a roda dentada partida, é de puro Génio!

Broken Gear Repair
Fab Muchada

Simple way to fix broken gear
you need a plastic steel epoxy, Popsicle stick, any mixing medium for your epoxy mixture and brush and detergent soap or dish washing liquid.

Duas dicas de Fernando Mattoso Lemos, 2 Adaptadores que unem o Arduino ao Raspberry Pi;
O primeiro, é o Raspio, um projecto que já ultrapassou quase 3 vezes o seu Objectivo de 3.456 Libras, e pode funcionar autónomamente, uma vez programado, ou comiunicar com o Raspi, como periférico:

RasPiO Duino Affordable Arduino Programming On Raspberry Pi

Alex Eames 

I want to get you into the wonderful world of Arduino programming, using your Raspberry Pi as the programmer. There's so much you can do with the ATMEGA 328 microcontroller - it complements the Pi perfectly and for many applications it doesn't even need to be connected to the Pi, once it's programmed. So I've designed the RasPiO Duino, which...
  • Has a capable microcontroller: ATMEGA328P. 32KB flash. 20MHz
  • 6 analog inputs for reading sensors (light, temperature,  pressure etc.)
  • 14 digital input/output pins for controlling and switching things
  • 6 PWM outputs for variable LED brightness or motor speed control
  • Can control up to 12 servos
  • Can exchange the microcontroller as it is socketed
  • Fits on the GPIO header and is programmed directly from a Raspberry Pi
  • Uses the Arduino Integrated Development Environment for programming
  • Is very keenly priced

O segundo, é o Arduberry, que já está à venda, com uma Empresa fundada para isso, e tudo:

Arduberry: Raspberry Pi and Arduino for the Rest of Us

Students, hackers, tinkerers unite!  The Arduberry is the shield you’ve been waiting for.  The Arduberry connects the Raspberry Pi and Arduino.
We love Arduino and we love Raspberry Pi.  We thought they should be together.  The Arduberry marries the Raspberry Pi and the Arduino.  Simple, elegant: all you need and nothing you don’t.

Um Instructable dum Forno Português, da autoria dum Entusuiasta Estrangeiro!
Ora toma!
Eis como podem fazer um Forno que serve para vários fins, bem à moda do Desenrasca Lusitano, que nos tem aguentado a todos nós, como Nação e Diàspora, contra ventos e marés, pela bonita idade de 800 anos...

How to Build a Portuguese Wood Fired Brick Pizza Oven

In this instructable we will describe how to build a real Portuguese brick pizza oven.
Portuguese ovens are characterized by higher dome than the Italian / Neapolitan ovens. What this means in practice is less intense heat. In all of these ovens the heat is reflected from the dome back onto the cooking floor and the lower the dome the higher the heat. While the Italian pizza ovens are made primarily for pizza (they cook other foods too, but most people buy them for pizza) the Portuguese ovens are made with cooking a variety of foods in mind: slow roasts, lasagnas, bread etc. For all of these you will need less heat than for pizza and hence a Portguese ovens can come in handy.

Este Instructable, vem com o seu Ficheiro 3D, por isso, podem finalmente usar as vossas Impressoras 3D num Instructable que faz sempre falta, uma gigajoga que acha os Centros em peças duma forma simples:

Center finder

I love tools and every now and then I also love tools to make live easier. This one is based on a one time tool from woodpeckers but not available anymore. So I decided to made one by myself using my 3D FDM printer.
Its a handy tool to mark the centre of a workpiece, just place the two legs around your piece and mark a line or point or draw a line with a pen trough one of the holes in the middle bar. Due to the parallelogram, the center is always found automatically.