I have 2 spindles from jianken bought through aliexpress. Both were around 1700 for the bare tool. One does 24000rpm, the other 30000. Note, if I were starting

I have 2 spindles from jianken bought through aliexpress. Both were around 1700 for the bare tool. One does 24000rpm, the other 30000. Note, if I were starting from scratch with nothing, I’d buy iso 30 stuff.