Feb 04

Gears design or the power of online wizards

Gears are a basic component in a verity of mechanisms, and therefore almost any design engineer will need to design or specify a gear at least once. Again, the power of the internet comes to support us, and can guide us quite quick from remembering that gear design is something that includes teeth to mastering the art of gears design.

eFunda – gears theory

Basics – gears design theory

while coming to design a geared transmission, there are many parameters that should come into account such as: transmission ratio, materials, speed, angles of transmission, space available, backlash, wear and many more. to refresh with the theory of gear design its always good to go to the following sources:

  • eFunda  – The theory is being reviewed, and terms such as “Addendum” and “Dedendum” will not sound bizarre to you anymore.
  • engineeringtoolbox – Is also a good place to remember the basics.
  • Wikipedia – As always, gives a very good review, sometimes too long (don’t forget to donate!)

Practical approach – Let me buy off-the-shelf


In case you don’t want to have all the theory, and just need some gears to insert to your design, there are great online suppliers, all sell the standard gears and differ mainly by service and availability.

  • SDP-SI – a well-known manufacturer of high precision standard and custom gears for a wide range of applications.
  • Misumi – Online catalog of mechanical components, ships worldwide.
  • McMaster – reviewed in a previous post, has also gears inventory and also their 3D CAD models that can be useful.

Quick gears design, I want it working by tomorrow

Sometimes, you don’t want to order and then wait, and you can compromise on a home made gears, (can be made of wood, plastics) you can use online wizards to generate the general form, and then import the output to your preferred CAD suite and go on

  • Woodgears – great site, gears that can be useful for any home made jig or machine, lets you print gears contour or download a software.
  • GearGenerator – Lets you design the transmission and download the files in SVG or DXF file formats (also from this author great charts tool)


Gear design is an art, and there are designers that dedicate their entire career to it, but if you need some gears as components for you, we’ve seen that the web can also help and lead you to the solution. this approach can be implemented also for other components as well may them be springs/bolts/cylinders or any other mechanical item (Theory/Suppliers/Online wizards)

Dec 28

3D CAD Software – and free options for makers

The main tool for mechanical design engineer is no longer the drawing board and the pencil but the 3D CAD software, it can be commercial such as Solidworks, Creo, Unigraphics, free/semi free* Sketchup, Fusion360, Onshape. Choosing between them might be a key for the project’s budget and timetable.

*Semi-free – Can be downloaded and used, under various limitations.


# Name Type
1 Solidworks Commercial
2 PTC Creo
3 Sketchup Semi-free,
4 Fusion 360
5 OnShape Semi free, WEB based
6 FreeCAD Linux

Table 1 – 3D CAD software

I’ll start by stating the obvious, we all have habits. A CAD tools is a habit, there are good and bad things about each, I think that it is good to know that there are different options instead of sticking to the known one. Most of the designers have a favorite tool – may it be from the University, or the first one that they used by themselves, and switching from one to another tool may take some time when the design process will be quite slow compared to the old known one.

Commercial 3D CAD


Commercial CAD such as Solidworks / PTC Creo Etc. are good and stable software, with lots of features, the professional mechanical designer will probably use a copy of these suite, it has lots of features such as: Weldments design, tubing, sheet metal, electrical routing, animation and kinematics analysis, There are many variations that the software may be used – “levels” of license (and price accordingly).

Both has a free offer for students and learners (free download):

Semi free 3D CAD software

There are good CAD software that are semi-free, it means that you can use it with no issue if you’re a student or a small firm / free lancer but they ask you to pay if you want to use it in more official manner. (which remindes the “Freemium” business model in software) these software suites are backed by big and reliable software companies (Autodesk / Google), there’s an interesting  new approach to this field with the new cloud based CAD software – OnShape (the veterans from Solidworks re-invent themselves), the good thing about cloud CAD is that you don need a strong computer to work. In addition, unless you design heavy and complicated design, the features offered by these suites are quite enough for your needs.


Free 3D CAD

There are also solutions for complete free and open source solutions, such as FreeCad that can be downloaded from here. I can’t refer to this software since I didn’t use it. But I assume it is basic since there’s no company that supports it. But – its free – Linux computer and FreeCAD, and you have a CAD station !


Few 3D CAD solutions were reviewed in this article, I hope that anyone can find the right solution for him, There are many more solutions in the market, (Inventor, SpaceClaim, Unigraphics…), all generaly match into the 3 categories, Keep designing !!!


Nov 21

Selecting the right material for a design – hands on manual

Material library

Material selection library

While working on a physical project, there’s a need to design parts, as chassis, parts of mechanisms, covers – and many more, even that there is an easy option to use pre-modeled parts as mentioned in my previous article (and in more to come). whether you use 3D CAD software such as Solidworks, Creo, Fusion360, inventor or even doing it the old way with pencil and paper, there comes a time to choose the right material to meet the requirements from the part.There are few practical steps in the material selection process, and in this article they will be based on a design case for a heat sink design. the article will show how using the web resources can ease the process and make it quick and productive.

The steps

The steps for selecting material will be as follows:

  • Selecting the right material
  • Finding a general purpose supplier, to learn what are the practical forms that this material can be supplied
  • Finding a specialty supplier that may have the material in more suitable form for the requirements.

These steps are quite similar whether its a metal for crane chassis or cloth for new sport shoe design.

Note – The suppliers in this article are ones that I use, but there are many more that serve the exact goal general/specialty supplier.

Since our design case is heat sink (Passive heat exchanger that transfers the heat generated by an electronic or a mechanical device to a fluid medium) we will start our design process by looking for the the right material, we can search the literature  or ask google “heat sink material” that will lead us through Wikipedia to find that aluminum is commonly used as heat sink material, and to be more specific Aluminium alloy 1050A. 

Heat sink

Step 1: Material selection using “Matweb” website

In order to learn some more about the material proposed in Wikipedia, Browsing to Matweb is very useful, MatWeb’s searchable database of material properties includes data sheets of polymers, metals, ceramics, and other engineering materials. results for Aluminum 6063 give us additional information about the different variations for this material and other important properties. Now, we have the material properties,  but we need to find actual  material that we can use, so the next step is materials supplier.

Material selection website

Step 2: Finding how the selected material is supplied using Scope website

Scope is a material supplier, I use often but there are many local suppliers, they all work by the same scheme – big stock and good website, you buy the amount from them or from their sub-suppliers (for small amounts), for our case Aluminum 6063 comes in various sizes so we can mill it and shape it to the exact heat sink we need, BUT maybe we can make it easier and faster ?!

Step 3: Searching for a specialty supplier for solutions using BTI-2XL website

Since heat sink is a known solution, and commonly used, maybe there is a supplier that sells pre-made units or profiles ? short search lead to BTI-2XL, small specialty supplier, and browsing in their site shows they have the exact heat sink that match the needs.




Choosing the right material for the designed part is a major step in the design process, in this article it was shown how to use the internet to find the right material that will answer the need, understanding that there are material suppliers (based on the supply area) and a big time saver and design aid is a material specialty supplier,  which can shorten the supply and design time with pre-made supplies.

The principal for material selection can be used to all material selection – the suppliers and sites may change but the working principle stays the same, nevertheless that are some times that a special material is required and a unique processing is applied, but this is a minority of the cases, unfortunately 😉

Nov 13

Online professional electrical and mechanical suppliers

In this post I will review major mechatronics suppliers (electrical and mechanical), these are who supply the motors, cabling, screens, LEDS, buttons, tools etc’. There are many suppliers: Mouser, Digikey, Rs Components, Arrow and many more. All offer good equipment, specifications and delivery. Essential for any project.

So, In the previous post I explained how to get 3D CAD models of the mechanical part required for the project, I’ll bet that most of the projects these days integrate some kind of electro-mechanical integration whether it will be small IOT device or 15[m] production line machine.

Stepper motor

Example: finding stepper motor (electrical mechanical part)

Let’s dive directly to the practicals – and get a stepper motor for our project, (used in every 3D printer, robot and printer) we can either browse through the menus:

Apply the filters and get the desired stepper motor (Or you can use the search option).

Important note:

One important note about these sites, they will stock the common items, and give you general idea of what is available in the market (very important) but if a special actuator is needed – more accurate, energy saver, faster, or any other feature – it will require much deeper research work in finding the right product and supplier, Good luck!

Nov 09

Faster 3D CAD design using online parts libraries

In this article I’ll explain how to 3D design faster by using on-line  parts libraries. Simple yet powerful method of saving time and building professional 3D CAD models is using online parts libraries. Selecting the desired component and  importing the 3D model into your CAD software is a time saver, McMaster-Carr site will also be reviewed as such source.

3D CAD Models – Time saver!!

As an mechanical design engineer, I am used to design parts and assemblies – following a specification (written on ice… ;)) and the time frame (yesterday) and – off I go, designing something that does this and that.

Heading to the CAD station (may it be Solidworks, Creo, Fusion 360 or any other) and start gathering the data to your work space, there are the major parts that need to be designed, mostly manufactured by the relevant technology (CNC, 3D printing, Sheet metal, milling, turning, laser cutting). BUT there are lots of items that still need to be included in the design such as bearings, springs, bolts,nuts, motors. All of these parts are needed to be in the assembly, but there’s ABSOLUTELY NO NEED to model them manually.

First – the principle – there’s no real need to model a M6x20 mm bolt or bearing 6902zz  since there are practically thousands of those models out there, you need to get one made and import it into your CAD environment. the files are stored in various sites and multiple file formats and after mastering the import process you’ll have thousands of parts ready to be integrated into your designs. you need to find the right site that stores them and download it in your favorite CAD format.

Using McMaster

McMaster McMaster-Carr is a big site with lots of parts, in all aspects of engineering, has parts from small needle bearings to generator sets and cranes.

The catalog is graphic and quite straight forward, by navigating through images and filters.

Here’s the selection screen for ball bearing model, Initially you choose filter the parameters:and then, click the link to download the CAD model the the desired format (.prt/.stp/.sldprt):

There are many more sites that share 3D models and useful information for mechanical design, that will be reviewed in the following posts,so keep posted!



Dec 26

KeerBot is Going to Bezalel Academy

Long time not seen – But Keerbot is back and is visiting the #1 art school! been busy in real life tasks and left this blog quiet for a while, and I am writing this post since KeerBot is Going to Bezalel Academy !!!


Some happy (unfortunately not technical) things happened – I got phonecall from an advertisment agency few months ago and they wanted to make a cooperation with me – but it didn’t eventually happen, and now for the really fun story – a friend of mine study at Bezalel in Jerusalem, and told me that my Keerbot project was mentioned by the lecturer. I felt proud, and immediately contacted the lecturer Dr Sarit Youdelevich to say thanks, and she invited me to give a lecture about KeerBot 

KeerBot Bezalel Lecture flyer

KeerBot Bezalel Lecture flyer


The lecture is planned to be on Dec 31, 2015. I’ll share the presentation and how it went in the next post. hope this will give me some encourgement to get back working on this project …

In the meanwhile you can have a look at my newest project (published last week) DIY Nail Puller, in my Instructables website.

DIY Nail Puller

DIY Nail Puller

Sep 01

RC Submarine Hack – Android controller (Arduino, Android, Submarine, Bluetooth)

For the new Instructables contest, New project: RC Submarine Hack – involves Arduino, Android, Submarine and, Bluetooth, For exact details and how-to see the here, downloads are below:

  • Arduino Sketch .ino – here (right click and download – might need to change file extension to .ino)
  • AppInventor .aia – here (right click and download – might need to change file extension to .aia)


 The (yet) UNHACKED RC submarine


Aug 05

Maker Must have – AfterShip – free package tracking service

As a maker, I order many items from all over the world (eBay, Aliexpress, DealExtreame, Seeed Studio, Amazon ,BangGood…). The probem is after I order them, I wait patiently for the packages. Until now I had to enter to each supplier and track the delivery via their site. NO MORE! – AfterShip – free package tracking service, does it for me.

AfterShip Logo

The procedure is simple – you open an account here, and then you can insert all of your tracking to one place and track them. The service supports over 200 carriers, all over the world, its free, and lately they published also mobile applications (AfterShip Android App, AfterShip iPhone app).

AfterShip Menu imageAfterShip can track your delivery, Send you notifications (email/sms), you can personalize the service or even integrate it into your site! I found it very useful and I think you might too. Enjoy.

Open AfterShip accout