Last week, while I was over in my Dad’s workshop checking out his latest wood working project I noticed some old discarded pen and pencil kits he picked up when he first started teaching himself how to use his lathe. The kits come with all the parts required to make a functional pen or pencil but lack the “barrel” (the part you hold) of the pen. Usually these pen and pencil kits are used in conjunction with wooden or acrylic “pen blanks” and a lathe to form a custom barrel. Since I’m not much of a wood worker (and I don’t have any pen blanks) I thought I’d use the epic power of 3D Printing to make myself a custom mechanical pencil.
I pulled down the spec sheet from Penn State Industries for the Executive Pencil Kit and got to work sketching out ideas for a pen barel design. I’ve seen quite a few mathematically generated geometrical patterns on Thingiverse lately, like this awesome printable bracelet and thought it might be fun trying something rigid and angular for the barrel, something that might be difficult to achieve through traditional wood working.
As usual I fired up my 3D modeler of choice, Google Sketchup and got to work. The way I figure it, there are two ways to generate a nice pen design in Google Sketchup the first is using the “Follow Me” tool like a lathe and the second is manually modeling the design using shapes and solid tools. I went with the second method.
I started by printing a blank cylinder a few millimeters high to check the dimensions and wall thickness of the barrel before designing something larger. This was a huge time saver as I was off by a few millimeters and a fully printed version never would have fit the kit’s brass barrel tube.
After finding the correct print dimensions it was just a matter of printing the full size pen barrel and heading back to Dad’s workshop. To finish one of these pens kits you need a Spring Loaded Pen Assembly Press, this press fits the parts in place. I imagine this could be done in a cheaper and more DIY way, but if you’ve got right tools for the job you might as well use them! After sanding down the barrel (it was just a smidge too tall) we assembled the pen and “TA DA” a New Hobbyist mechanical pencil was born.
As you can see from the photos I used a hexagon as my base shape and extruded and twisted it as I went. There are some small ergonomic changes I’d like to make (tapering the edges and narrowing the outer diameter a bit), but once the kit is pressed together it’s pretty tough to disassemble. The pen has a pretty uniuqe look and it’s a fun conversation starter, it also makes me wonder what other wood working kits could be turned into “Makerbot kits”…
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- Generating GCode in ReplicatorG
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- The pencil kit
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- Sanding the end of the pencil tube for a better fit
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- Setting up the pen/pencil assembly press
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- Connecting the writing end of the pencil
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- Connecting the back of the pencil
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- Finished pencil
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- Glamour shot #1
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- Glamour shot #2
I found a build your own mechanical kit in my Dad's wood shop over the weekend and decided I'd try my hand at mechanical pencil design with some ABS rather than wood.
The barrel is designed to be used with the "Executive Pencil Kit" from Penn State Industries. pennstateind.com/store/PKEXEC-PCL.htm
I tried to make a geometic pattern that would be difficult (at least for me) to duplicate using traditional wood working methods.
They sell quite a few customizable wood working kits that I could see being repurposed for 3D printing (plastic working?).
Overall the pen looks cool and is a great conversation starter. More details and photos from my build are available in my blog post here: thenewhobbyist.com/2012/02/wood-working-on-the-makerbot-thing-o-matic/
My name is Chris. I'm a Chicago area maker and 3D printing enthusiast. This blog is a home for my DIY projects, 3D designs and other miscellany.
