CNC Spindle Contruction Help

[Yosmany325]

Hello everyone. I'm new in this forum and maybe my question is not for this but I don't know where to ask for this. I have searched on internet regarding this but I haven't find something like I want.

Right now I'm trying to make a CNC machine, mainly for PCB drill/mill. My question is where I can find information related to spindle construction, I mean, DIY spindle construction.

If someone can answer the following question I will appreciate much his/her help. Thanks in advance.

The questions are:

Why is needed an spindle?
Why not connect the chuck to hold the drill bit directly to the motor shaft?

I'm planning to use an RC brushless DC motor (A2212/13T KV1000), for this motor:

Can it be operated with the rotor reversed? (See the attached picture)

I have seen some DIY spindles, they use atleast two ball bearings and a shaft. Can I use something similar in the following scheme?

Motor_Shaft [3.17mm] + Coupler [3.17 --> 3.17mm] + Shaft [3.17mm] + Chuck [with adapter for 3.17mm]

Thanks in advance for your help.

 

[D.A.(Tony)Stewart]

The problem with small spindle motors is poor bearing vibration and "runout" or wobble.

The trick is to find a dummy spindle motor with a 0.5 or 0.75" shaft and cascade this spindle driven by the smaller motor to reduce the runout.

 

[Yosmany325]

Ok, thank you very much for your help. Also, if possible, can you answer my other questions? Thanks in advance for your help.