Why 6 slots on rotary tables , faceplates etc.?

[Alcap]

On my rotary table it has 6 T slots also on my lathe it uses 6 , which lead me to make a fixture plate but why are some 4 or more then 6 on some ? I would think 4 you could block or make centering easier ?

 

[Braeden P]

say you have a part with 4 bolt holes line it up and bolt it down same way for something with a 6 bolt hole pattern and they are used very rarely but when you do use them its a time saver

 

[RJSakowski]

The faceplate for my Atlas/Craftsman 6" lathe has four slots , as does my Tormach 6" RT. My Grizzly 602 8" faceplate and my Enco 12" RT have eight slots. Unlike a four jaw chuck which has some means of control for positioning, I don't think it matters much regarding alignment.

I suspect it has more to do with the remaining surface area. More slots mean less surface area so smaller faceplate and RT's would have fewer and larger ones more.