Homebrew PCBs

--- In Homebrew_PCBs@y..., milwiron@t... wrote:
> At 07:44 PM 06/11/2002 EDT, you wrote:
> >Denny:  I ordered one "to play with", too; thinking, for THAT 
price, no 
> >biggie either way.  Was curious about the "Sioux" model that costs 
nearly 
> >twice as much in same catalog, thought.  Wonder if that 
is "noticeably 
> >better"?????
> 
> Hi Jan,
>  Like most industrial tools I suspect similar die grinders by 
Dotco, Sioux,
> Nu-Line or Foredom are substantially better, though they do cost a 
couple
> hundred bucks more. I have tools by Sioux and Foredom/Engis in the 
shop,
> you can't kill 'em with a stick. The Enco seems to be a decent 
value for
> the money so I'll give it a shot for starters. Unlike my Sioux and 
Foredom
> tools I don't expect to see the Enco grinder still working daily in 
my shop
> in 20 years. ;-)
> It would probably be worth keeping a spare Enco on hand and/or 
making a
> universal V-groove mount to accept a better quality grinder in the 
future
> if it were needed.
> 
> >Clippard makes some super-fine electropneumatic valves, and those 
coupled 
> >with their piston-actuated two-way valves might make it possible 
to turn 
> >on/off the air except when this thing is "going down" for a hole.
> 
> Adding a solenoid valve to the mill is almost a given anyhow, I 
think
> you've got a good idea shutting the grinder down whenever possible. 
There's
> very little rotating mass so spool time is very short.
> Denny

Denny:  Just got in the Enco 1/8" "air Die Grinder" with VERY nice 
1/8" collet, precision collet-nut and nose, and cloth braided O.D. 
air-hose with flexible muffler over that.  Runs VERY fast, and 
exhaust is out the top, but without the muffler-tube over the hose, 
it is very noisy!  Eats air!  The average 3/4 hp compressor would 
probably run more than 50% of the time, if this thing was left on, 
with nothing else using the same air.  I only played with it "out of 
the box" a minute or two, and it gets rapidly warm in half nearer the 
collet, so I guess it needs some 3-1 oil squirted down the air-hose, 
first.  We'll see.   I have no immmediate application, as my PCB-
drill has that 400 Hz, 12,000 motor, but looks like this might work 
if a cleverly-machined hardened/ground shaft-jacket were machined 
over it, and it then used in a linear ball-bearing arrangement.  
Else, it would have to be mounted in a kludge with linear bearings, 
etc.  The alum. body is 15.5 mm (0.610"), so would take some work to 
use it in a linear ball-bearing mount.