On Wed, 18 Aug 2010 12:53:49 -0500, "Pete C."
wrote:


Bob La Londe wrote:

"Ignoramus11933" wrote in message
...
As I was messing around with text engraving, I realized that it would
be very cool to have a high speed spindle.

There is, apparently, a wide variety of purpose made and adapted
devices that are used for this:

http://www.cnccookbook.com/CCHighSpeedSpindleAddOn.htm

The best so far, looks to be this:


http://www.cnccookbook.com/img/Other...Manifold_1.jpg

This is a Bosch Colt palm router attached to the quill. It seems to be
nicely made, and low profile.

In my case, I can use a changeable toolholder to do the attaching, so
that it is easy to take off:

http://www.shars.com/products/view/1...nd_Mill_Holder

This way, I could run a 1/8" end mill at 30,000 RPM, without using the
main mill's spindle bearings. I would use a brake to hold this
assembly in the quill.

It would be, as I said, a quick change setup, easy to be swapped
out. I would just need to figure out a safety interlock mechanism, so
that the main spindle would not be turned on accidentally with this
thing mounted.

It would seem that a holder is easy to make from 6061 or some such,
and the whole project can be done under $200.

I engraved some text yesterday, which took something like 19
minutes. I did it at 2,400 RPM. At 30,000 RPM, it could take only 1.5-2
minutes.

I guess it depends on what you mean by engraving. Engraving is usually done
with a spring loaded bit holder that is dragged (not spinning) along the
surface of the material.

Actually, most engraving *is* done with a rotating bit, usually fixed,
but sometimes in a spring loaded mount. All the plastic signs and
nameplates you see are engraved with a rotary bit. Most engraving on
stuff like anodized AL is also rotary cut (or lasered). Drag engraving
is the exception, not the norm.

Iggy will find a high speed spindle and a nice carbide rotary engraving
bit work nicely to engrave lettering and markings on aluminum or plastic
enclosures which can be paint filled for a very nice result.

Indeed. Pete is quite correct. A single flute cutter is most often used.

See Ebay ..search terms Gorton Cutter or Gorton Engraver followed by
engraving cutter

Gunner, with a Gorton 3-Z pantograph

--


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