There has been a buzz in the keyboard community recently among fans of smaller form keyboards. Months ago, a few among us had gotten their hands on Kailh's new low profile switches. They have a 1.5mm throw to actuation (3mm total) and are roughly half the height of a typical switch making them desirable for portable/travel keyboards. Until now, the Cherry ML has been the only reasonable sub-standard sized option, but complaints about scratchiness and sticky off-presses have prevented their universal acceptance among mechanical keyboard aficionado. Reports from reliable sources have given high marks to the new Kailh switch given its compact size.
The problem now is caps. Manufacturers are just now beginning to offer compatible keycaps for the PG1350 but only in a flat, laptop style profile. I prefer a cylindrical dish profile for better feedback and was looking for another option.
The stem depressions in the 1350 is similar to the Cherry ML but the Cherry's off-centered placement keeps the cap from allowing the switches full range of travel. I considered either casting all new caps out of resin but preferred having legends and was looking for a less labor intensive process that would yield consistent results. I decided to try taking the prongs from a donor cap and adhering it to another that had the prongs removed. This would allow the centering necessary for full travel.
The first step was to make a jig and cutting the cap top to the desired size.
A scrap of aluminum is being roughed in to accept a ML cap.
I milled a groove to further assist the holes for the cap prongs to keep the cap from moving under the milling forces.
Using a low speed, the mill cut the plastic cleanly and without burning.
The contour on the cap top was later sanded down flat to better conform to the other cap's underside.
Here it is glued up using CA adhesive. The donor cap was cut to perfectly fit the underside of the other cap. As it turned out there was a little play in the vertical direction so my next cut will be adjusted for that. Matching the two pieces closely is necessary for consistent indexing and final results.
The fit is good. The cap lays flat with the switch housing and has full range of motion.
It should take about a minute to mount the donor cap, mill it, and remove it from the jig. Sanding the cap top flush, glueing pieces together, and misc. clean up another minute or two. I should be able to prep 55 caps for my next keyboard in less than 3 hours, which is a lot faster than casting or milling a whole set.
