Carriage pawl for Monroe model L and LA calculator
by robertbaruch, published
This is a carriage pawl for a Monroe models L and LA mechanical calculator. It is part of the zero-setting mechanism for the carriage, where you turn the handle one way to zero out the upper bank of digit dials, and turn the handle the other way for the lower bank. The carriage pawl specifically prevents the opposite bank from turning.
Download the files carriage-pawl-outline.dxf and carriage-pawl-reveng.scad and put them in the same directory. Then use OpenSCAD to render the object. You'll probably have to zoom in since the part is small.
The dimensions are in INCHES.
You can then export to STL (or just download carriage-pawl-reveng.stl) and send to Shapeways, for example, to make the part. Although I'm not sure any 3D printing process can render the details on this part. Make sure you make the part in METAL, because you will have to bend the tabs to get the final thing. See carriage-pawl-reveng.png (or pdf or ai or svg) for details.
One calculator requires TWO of these pawls.
This pawl will also fit on any L-series calculator (e.g. LA, LA5, etc).
The reverse-engineered technical drawing is in carriage-pawl-reveng.[ai|pdf|png|svg].