Keyboard Builders' Digest / Tips & Tricks
LPX keycap
LPX is an FDM-printer optimized Choc keycap design by u/levpopov.
Published March 23, 2022
Shortly after teasing it, levpopov published the STL and STEP files of the LPX keycap profile.
While tweaking my keyboard project I’ve ended up designing a brand new keycap profile - levpopov.
These caps were designed in Fusion and, along with the files, the author published a detailed printing/slicing instruction as well.
Some highlights:
- Choc stem for low profile switches
- Compact. 18% smaller footprint (compared to MBK) allows tighter key spacing.
- Contoured saddle top surface similar to Chicago Steno.
- FDM-optimized to make it easy to produce in small batches in a variety of colors/finishes.
The compactness of the LPX – without sacrificing touch surface area – results in 18% smaller footprint compared to MBK while maintaining the same finger contact surface. This allegedly allows for "more ergonomic keywell designs" with tighter key spacing.
In addition, this results in reduced finger movement while keeping enough spacing to prevent accidentally hitting adjacent keys.
According to Lev's measurements and calculations, LPX is 15.8x15.1 vs MBK's 17.3x16.3 (so ~18% footprint area reduction), but the top surface that the finger touches is identical in size. The standard Choc cap (17.6x16.5) and Chicago Steno are even larger than MBK.
How may this affect your key spacing? You could tile LPX in a flat grid with minimal tolerances (i.e. ~16mm x ~15.5mm), but that's not the goal – in Lev's words: "while reducing vertical travel within each column is desirable, reducing horizontal spacing between all columns would probably make the board feel cramped".
Instead, LPX is meant to shine in Dactyl-like keywells.
LPX has tiny bezels so that you can rotate the caps in a keywell more aggressively, both minimizing travel within the columns and the side to side movement of the index finger for the inner columns (i.e. the innermost column #1 gets rotated on the side to bring it closer to column #2).
With smaller caps you can also rotate the corner keys in XY plane to reduce reach, as well as add a pinky splay to the pinky column without having it clash with the ring finger column.
On another note, the "contoured saddle top surface" feels similar to Chicago Steno, with a slight valley in the middle "gently hugging your finger pad".
According to Lev, this results in an improved feel compared to the spherical MBK and cylindrical scooped chocs (like this one and probably MCC too).
Enjoy: https://github.com/levpopov/LPX
Published on Wed 23rd Mar 2022. Featured in KBD #71 (source).
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