The top brand U.S. Machine Tools

Dear sirs , I'm a market researcher in a machine accessories manufacturer, I'm doing a research of famous U.S. Machine tools manufacturer , all I know about the brand of U.S. machine tools brand is :
Gleason
HAAS
Hardinge
Hurco

I know there still have a lot of famous Machine tools manufacturers in U.S.A. , but I don't know how to collect the information , So I came here looking for help, I'm very grateful for all your help!