TOG’s laserjet printer was mostly working, but the two buttons on top were stuck and unusable. Each button was supposed to have a little right-angled lever connecting it to its microswitch. The problem was that one lever had come out of its mounting, and the other one was missing altogether.
![HP2200 missing button lever Button mechanism removed, showing where the missing lever should be.](http://www.tog.ie/wp-content/uploads/2014/04/problem-150x150.jpg)
Missing. Gone. Not rattling around inside the printer, or sitting in a corner of the classroom. Just gone. But we have one lever left. If only there was some way we could make a copy of it…
The part is composed of a few straightforward shapes which were modelled in OpenSCAD.
![Measuring the part for modelling. Part, sketched diagram and calipers.](http://www.tog.ie/wp-content/uploads/2014/04/measuring-150x150.jpg)
![Building the model in OpenSCAD. OpenSCAD screenshot](http://www.tog.ie/wp-content/uploads/2014/04/openSCAD-150x150.png)
Then the design was printed on the 3D printer.
![Printing in progress. 3D printer head and half-finished print.](http://www.tog.ie/wp-content/uploads/2014/04/printing-150x150.jpg)
The first print didn’t work because there was too much of an overhang. The second, improved design didn’t stick properly to the bed (small fiddly prints benefit from a brim). The third one came out nicely.
![The learning curve. L-R: original part, two failed prints, successful print](http://www.tog.ie/wp-content/uploads/2014/04/prints-150x150.jpg)
After cutting away the brim and overhang support material, the new part fits under the button…
![Good as new. Same button mechanism, now with two levers.](http://www.tog.ie/wp-content/uploads/2014/04/fixInstalled-150x150.jpg)
… and the printer buttons are working again.
![Printer buttons working again. Grubby, but working, printer buttons.](http://www.tog.ie/wp-content/uploads/2014/04/fixed-150x150.jpg)
(And if your HP2200dn has also lost its button levers, the STL file is up on Thingiverse.)