"Bob La Londe" wrote in message
...
On 9/26/2019 8:46 AM, Bob La Londe wrote:
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If an air blast is useful for that sort of thing, what can I do to
use the air more efficiently. I have dismissed vortex tubes out of
hand. I have made one, and I have a commercial one, and they both
waste a lot more air than any benefit they might provide. Heck, you
get some cooling affect as the air expands out of any nozzle. I was
actually thinking about things like a better nozzle design on the
air blast to get a predictable cone of air, and making a ball mount
with a slip clamp to hold the air nozzle so it can be directed to
exactly surround the tip of the mill with its cone of air.

Side Note: I setup an old Venturi vacuum pump on a magnetic base
for some steel milling on my middle weight CNC mill and it worked
great. Work piece came off the machine barely warm after an hour of
cutting. Same with the mill. Lots of blue chips. I had a pretty
good stream of air, but the compressor didn't cycle on as often as
with my straight pipe air blast. Both have a ball valve for flow
control. Now to look at redirecting that vacuum port to reduce
likelihood of picking up chips...


You can use these tapered drill bits to make internally and externally
tapered nozzles like I described, which are more efficient if you
gradually open up the bore to allow only as much air flow as you need
at full air line pressure, without an energy-wasting throttling valve.
https://www.amazon.com/Tapered-Drill.../dp/B0007UQ2FK

The external taper helps draw outside air into the flow, somewhat like
the venturi aspirator but simpler to make.