Eversharp introduced its Capillary Action (CA) ballpoint in 1946 in a rush to market intended to head off a challenge from Reynolds. The product was poorly designed, untested, and resulted in so many returns because of poor performance that Eversharp was financially crippled to such an extent that it never recovered.
The CA refill was fitted into conventional capped pen bodies in both the Skyline and Fifth Avenue pen lines and into a clickable cap-action ballpoint as well. The major design flaw was that the actual rolling ball was a permanent part of the pen and the refill screwed into that ball unit. This opened the way for the refill to dry out, for the ink in the refill to air lock and fail to make its way to the rolling ball, or for the ink to leak at the joint.
No modern refill is designed to fit into the vintage CA pens. A number of adaptations have been described on Fountain Pen Network and by Richard Binder and other pen experts. Most of these involve precise cutting of an original CA refill so that it becomes an adapter to hold a modern refill.
Some time ago I purchased a Skyline CA with its original non-funtional refill, but I had neither the skill nor the machine tools to make an adapter from the refill. By happy coincidence, I happened to have a Pilot “Birdie Switch” ballpoint/pencil combo that uses an unusual and proprietary ballpoint refill. I looked at the Pilot refill and realized that it looked to be about the size of the CA refill, so I tried it. To my astonishment, it was practically a press fit into the opening in the CA pen’s nose cone.
This turned out to be a far simpler way to adapt the old CA pen to use a modern ballpoint refill. While the Pilot Birdie Switch refill is definitely not common, it can be had online from several vendors for a very reasonable price. The look of the finished conversion is quite similar to the original.
The pictures below show various aspects of the conversion. Click on any image to open the gallery with enlarged views.