Homebrew PCBs

Richard wrote:
> 
> Stefan, you said the 30eur micromot was 'much better'
> than the 100eur IB-E ??  In what way?

I think he was referring to the price being 'much better'. The quality 
is questionable, since I believe you get what you pay for (usually :o). 
The more expensive spindles on the Proxxon web site state they are 
suitable for 'extended use'.

> 
> It seems that any fluctuation in feed-rate, play in the Z-axis,
> or variation in board material, might be making the bit
> take far too big a chip-load for the low 30krpm speed.
> 
> Just a theory... <g>

Most probably due to the poor round out of the Dremel.

> 
> Is anyone using anything above 30krpm?  Which ones,
> and what did they cost?
> 
I think thats getting into the area of CNC PCB spindles.
How about something like the good old Westwind D1733 (just kidding)
http://www.gsilumonics.com/product_data_sheets_en/804.html


27000 RPM is ok for 0.017" (0.45mm) carbide drill bits provided you 
limit the feed rate, I use them with my 27000 RPM Bosch GSS27 mounted in 
a home built *hand* operated drill press. I've drilled literally 
thousand a hole and have only broken them by carelessness, like swinging 
the PCB around and knocking it, or like drilling a hole in an existing hole.

Sub US$300 pneumatic die grinders go well above 30kRPM, but do you have 
the air to drive them ? When you add the great big thumping compressor 
in the corner of the garage, it'll kind of makes you have second thoughts.

Let us know if you find a hobby affordable electric spindle capable of > 
30kRPM.

Adam