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.

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:  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!





Great ideas begin in the simplest forms.  A sketch on a napkin.  A doodle on a scrap piece of paper.  A few words to solidify the idea that has been formed in the mind.  And the sketch or doodle, the short sentence or scribble, all start with a pencil.  That’s why I’ve thought a fitting project for 2017 is WrTie, a titanium mechanical pencil.

This project symbolizes my desire to do things different.  WrTIe will be a product designed to last a lifetime and pass onto your kids (like that pocket watch you received from your grandfather), a project that challenges design and manufacturing skills, and my desire to be an inspiration for everyone working in their garage.  And that’s where great ideas start.

The real question is can a small shop with manual machines and one man design, prototype, and manufacturer something so simple … yet so complicated?  This is a product made with a material that is difficult to manufacturer with even the best equipment.  And I’ve never machined titanium.  Not even once.

What will follow over the year is a series showing my progress on designing, prototyping and manufacturing a mechanical pencil made from titanium.  There will be product tear downs, unique designs, tiny o-rings, CAD software, research, guesswork, calculated risks, material investigation, tool design and selection, deep hole drilling, tiny machining, the help of friends, many failures, frustrations, lessons from craft beer, and I hope in the end success.

I haven’t written or designed anything.  This is not scripted.  This isn’t a Kickstarter campaign.  Through the power of video you will be coming along for the journey, every step of the way, watching ever failure, and every success.  I want to learn and do something productive, and I hope you do as well.

And in the end if it all works, I hope to have something special that I can use every day.  The drawings, the lessons learned, the tricks discovered, will all be here.

To show your support, I ask you to subscribe.  I will start in early 2017.

Now I need to get this VFD put on my lathe.