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MPCNC Pen holder

MPCNC Pen holder

MPCNC Pen holder

I’ve recently finished up the construction of the fantastic Mostly Printed CNC.  It looks like it will be a very useful tool and a good compliment to the other tools in my shop.

To test it out, as well as to make up large templates, I wanted a good pen holder.  I started out with a MPCNC sharpie holder, and it works great, but the sharpie itself leaves a pretty wide line.  To have the greatest amount of flexibility I designed and printed an adapter that allows a Papermate 1.0 pen to be used in place of the sharpie.

3D printed pen holder in sharpie holder beside pen and spring

3D printed pen holder in sharpie holder beside pen and spring

The STL files are offered both as a single unit as well as one that is split if your printer is height challenged.  In the latter case use some crazy glue to bond the two pieces together and clean the bore up with sandpaper.  I also used a bit of 1/4″ threaded rod to quickly remove any glue flash from the bore of the penholder.

How does it work?  Wonderfully.  The accuracy is spot on – even going over lines already drawn, which is what you’d expect, but when I used a shorter pen holder there was a bit of wobble.  The longer unit works out great as can be seen in the picture.

Now, the one thing this doesn’t do is hold the pen up when the holder is retracted – that means there will be a pen line that follows the tool path. If that is ok for your intended use this is a great bit of kit to add to the MPCNC.

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