Re: [CAD_CAM_EDM_DRO] 1KW, 30KRPM Router as a Spindle/Motor?

In a message dated 6/9/2004 5:21:45 PM Central Standard Time,
cnc@... writes:

That said.. If this is the dream, then where's the heartbreak? What's
the catch?
Why shouldn't I do this? :)

Cncnoname in UK: GOOD question. I think perhaps even the BEST bearings used
in woodworking routers have more runout than one would expect for even
"home-workshop metalworking" purposes. This MIGHT become more pronounced, using
those tiny mill-bits you mention. Also, the mass of a router's armature is so
much less than a properly-built metalworking spindle that vibration from
NOISE-alone would be much more pronounced on the tiny bit that one held in a
precision collet in a massive and precision shaft in proper precision tapered-roller
or angular-contact bearings. Just a guess, mind you!

Further, even the finest woodworking routers I have seen have relatively
SHORT collets, of probable questionable axial precision, so that the bit would
"show up" a couple hundredths of a mm different, each time inserted/tightened
into it!

Now perhaps if all the metalwork you ever contemplate is into 6061 to 7075
Ali, with nothing smaller than a 1/8" (3 mm!) solid-carbide, two-flute bit,
using proper coolant/lube intended for use with Ali, it may work fine for years,
so you would think I had no clue whereof I spoke. Then you would try tiny
bits, say, 1.5 mm. dia, and the best you could get out of ANY was 7 or 8 cm of
cutting-path, 2 mm. deep, and you would wonder why forever. For such "tiny" and
high-speed milling, one MUST spend some quid, and get the PROPER quill!
Jan Rowland, aka Big Ugly


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