"slot tuners"?

[Steve VandeWater]

Hi, I bought an old bowlback to rob parts from awhile back (for $10). The one odd thing I noticed was that the tuning machines have slots for the strings to fit into instead of holes. The photo below shows them.
I have cut them in half to use on a 4 string project. And yes, I realize I butchered them.
I've never seen slotted pegs before. Were they common?

[MikeEdgerton]

I've seen them on some older guitars over the years. I don't know how common they were.

[pops1]

Fender used them on guitars, they are a nice design. On the Fender ones there was a hole in the center and you put the string straight down in the hole and laid it thru the slots and wrapped as normal. No sharp string ends to poke. Easy and quick to string.

[jesserules]

Have them on an old Martin Hawaiian guitar. Sort of mind-scrambling at first, but they work fine once you figure them out.