"¿Qué clase de maquina tienes?"
If I wanted to know what kind of machine or pump they are using could I say que clase de maquina tienes?
Hi and welcome to the forum.
Yes, "¿Qué clase de máquina tienes?"
Just don't forget the accents: ¿Qué clase de máquina tienes? Máquina stresses the first syllable.
You would also want to use tienen instead of tienes if you were asking what kind of machine they are using.
"Clase" isn't very precise. It might give you the difference between an orbital sander or a belt sander for instance. If you need more detail you will want to prepare more specific questions.