It's really tough to get metal stems perfect due to shrinkage.
One reason why we need ceramic spacebars.
We do already.. they're called PBT
Well... just my little joke about the surface feeling of PBT. Actually, it's hard to make ceramic items with accuracy due to the shrinkage when sintering... So they would probably turn out even worse.
I'm actually okay with ABS spacebars for the most part. They're lighter, so they match the other keys better (due to the large size) if you have a thick PBT or POM set and in most cases I hit the edge of the bar rather than the top surface, so the texture and feeling of the material matters less than on the other keys. If you flip the bar, though, it's nice to have the same material as all the other caps to keep the feeling consistent, though.
