Pentel P209 Teardown

wrTie has begun!

To start off my titanium mechanical pencil build, called wrTie, I decided to teardown a number of different mechanical pencils for inspiration and design ideas.  I find the mechanisms in mechanical pencils very interesting.  I also find the manufacturing processes that are used exceptionally interesting.

Here is a teardown video of my favourite mass produced mechanical pencil: the Pentel P209 (0.9 mm version).  The Pentel P20x series (there are 0.3, 0.5, 0.7 and 0.9 mm models)  has been around for a long time.  It is exceptionally well made given the price point it is hitting and the parts involved.  There are 12 parts in total, including 5 fully machined parts.  A number of the parts require plating.  There are 2 parts that are molded out of plastic.  And then it has to be assembled!  You can buy a Pentel P209 for less than $5 in the United States and less than $7 in Canada.  That’s actually pretty crazy considering this pencil contains machined parts and even more so once you consider that Pentel is probably selling it to it’s retailers for less than half of what they are retailed for.

https://youtu.be/tM4h61_BLKQ

The heart of the Pentel 200 series is a removable fully contained feeding cartridge.  The cartridge features a number of machined components in the feeding mechanism.  The components are probably massed produced on swiss style screw machines (a lathe but instead of the carriage moving the spindle moves in the Z direction – often called sliding headstock machines).   These machines could be cam actuated screw machines or they could be CNC controlled units.  CNC swiss style machines, like the ones produced by Star or Citizen, are really interesting machines.  Here is a video of a Citizen L20, one of the more popular CNC swiss machine that you will find today:

The Pentel P209 cartridge has been used in a number of titanium mechanical pencil builds on Kickstarter.  I can’t confirm it directly as I haven’t purchased one, but check out this project (you have to scroll about half way down and you’ll see a picture of what looks to be the Pentel cartridge: https://www.kickstarter.com/projects/cogent/titanium-mechanical-pencil-and-titanium-pen.  Given the Pentel’s design, you could easily make a new mechanical pencil by machining a new outside body for the Pentel.  I won’t be doing that because I think it is too easy!

 

 

 

Terrible Design 101

Recently I had to fix a toy for the new addition in the family.  It was a car seat toy.  The toy is suppose to play a song when you push the dog’s nose.  We’ve had this toy for a few years and all it needed was a new battery.  I made a short video going through what I needed to do to change the battery.

I hate tamper proof screws.  The only point to them is to either sell more tools, or force people to throw stuff out.  They don’t keep people out.  People who want to get in will get in, and people who don’t want to will not.  And keeping people out of products so they can’t change batteries doesn’t make any sense whatsoever.  Then there is the problem of end of life.  How many people would just chuck this item into the garbage?

End users or consumers should always be able to remove and replace batteries without the need for specialty tools so they can remove the batteries before they dispose of the device, or prolong the life of the device.  Why is this such a big deal?  Devices with non removable batteries cannot be automatically processed by waste recycling facilities (because these facilities grind up the entire device – which would cause major issues with batteries).  This forces these types of devices to be shipped overseas where low cost labour disassembles them.  Often kids are doing this work, and the waste is not disposed of properly.

Apple is one major manufacturer that insists on fully enclosed non removable batteries.  This is terrible, but it helps their agenda: sell more devices or sell more over priced service.  Numerous reasons are given for built in batteries in small electronic devices, but in reality they don’t have any merit.  I have a inexpensive ($100) Android phone with a removable battery and it works great.  And if the battery needs to be replaced, I don’t even need any tools to replace it.   And when the device fails I can remove the battery and send them to appropriate recycling facilities, instead of across the globe.

We really have to stop designing for the dump and quickest assembly, and start designing for service and longevity.