[Coco] Schematic for external PIA, cart protoboard.

[Richard E Crislip]

On Sat, 7 Feb 2015 14:24:00 -0500
Gene Heskett <gheskett at wdtv.com> wrote:

> On Saturday, February 07, 2015 12:22:06 PM Richard E Crislip wrote:
> > On Sat, 7 Feb 2015 11:25:13 -0500
> > 
> > Gene Heskett <gheskett at wdtv.com> wrote:
> > > On Wednesday, February 04, 2015 08:23:53 PM
> > > camillus.b.58 at gmail.com
> > > 
> > > wrote:
> > > > As I remember, we used to have a pia controller board that just
> > > > needed to be inserted. It had address selection and decoding,
> > > > and some LED on one port while the other port was usable
> > > > 
> > > >  as input. Let me look to my stuff maybe I have some info still
> > > > 
> > > > laying around.
> > > > 
> > > > 
> > > > cb
> > > 
> > > George Ramsower uses a coco or 2 to drive (slowly) some of his
> > > home made cnc machines.  Perhaps he would be willing to share some
> > > schematics of the interfacing he has built?
> > > 
> > > Cheers, Gene Heskett
> > 
> > That reminds me... have you heard of LinuxCNC? I saw it demoed
> > Thursday night.
> 
> Naww, gee Richard, only since it was called EMC at 2.00 a decade and
> change ago.  Now its at 2.7-pre and running very nicely indeed. In
> terms of retrofitting machines to be cnc controlled, our free
> software has at least 25% of the market and several are actually
> making a living converting machine that either have a dead controller
> or were manual in the first place.
> 
> The other 75% of this market belongs to Mach3, based on windows, and
> is a huge slow kludge compared to the direct access linux allows to
> the parport. Sure, we have a thriving market in interface cards for
> really high performance machines, but we can live without it on
> smaller slower anyway hardware.  Windows cannot, and IIRC Mach3
> requires a special interface card, and of course a $175 licence.
> Windows folks simply do not know any better. This is good enough that
> a very fancy $200k machining center at the Toy factory in southern WV
> is using linuxcnc to drive that multiaxis machining center to carve,
> from a solid block of ALU, probably in the 7078-T6 alloy range, the
> racing engine blocks that Toy, just like Honda etc, rents to the big
> names in racing.  That is not widely known but there was at one time
> an nominally 30 minute movie on you tube showing both the control
> panel, and the machine thru the safety glass, carving it, truly a
> work of art as there was not a single surface in that whole completed
> engine block that was not machined, to .0002" tolerances.  One such
> block was about 4 hours being carved, and the swarf filters in the
> coolant system will have recycled about 300 lbs of ALU cuttings from
> the original block of starter ALU alloy.  That stuff is tough even
> when shielded from the air so it doesn't oxidize near as fast, but
> that 4 hours also wore out a box of carbide inserts for every tool in
> its auto changer rack per block.
> 
> I have carved some stuff from solid ALU a lot softer than that, and
> its 10x as hard on tools as decent steel.  To really do a good job,
> you must arrange a spray of coolant that hits the raw ALU 10
> thousandths of an inch behind the cutting edge that made it raw. 
> 
> Yes, ALU is a very reactive metal when exposed to anything with
> oxygen in it, forming an oxide film that is the 2nd hardest substance
> we know about, doing it in about 50 microseconds. The huge majority
> of the heat created when machining ALU is not from the friction of
> the cutting tool but from the heat of this instant oxidation as the
> raw metal is exposed to the air.  So tool coolants are mixed to have
> as little free oxygen as is possible, and applied, usually by a mist
> spray directed at the bottom of the tool so the ALU is re-wet and
> sealed from the air, as quickly as its physically possible to do.
> Big machines like the one at Toy effectively run in a sealed
> environment, with coolant pumps capable of 1000 psi.  And the
> enclosure if well enough sealed, might even be flooded with dry
> Nitrogen gas to displace the oxygen.
> 
> Did I not show you the two machines in an outbuilding in the back
> yard when you were here?  If not, I really must be slipping in my old
> age. I better call the paper & put in an adv for a keeper in that
> case. ;-) I think the lathe has been converted after your visit
> though.  Ball screws , the whole maryann.  No hand wheels on it, its
> run, when running by hand, from keys on the keyboard, same as the
> mill has been for yonks, but it too now has ball screws in the table
> drives.  Not yet for Z (head up & down) but its accuracy is now in
> the +-1 thou range anyway with the aftermarket screw I do drive it
> with.  But its grown some brackets on both sides of the head casting
> that about triple its "wheelbase" by holding ball bearings that ride
> the post casting.
> 
> Cheers, Gene Heskett

Actually you did show them to me and I believe you were using Linux...
or was it the CoCo... naa it was Linux to run the machines. When I saw
the GUI during the demo, I thought it looked familiar. I am not
surprised that you already knew about it.

Talking about milling a solid block reminds me of the day in metal shop
we were trying to cut down and trim off chunks from a solid block of
aluminum to melt down in the furnace. It was a struggle but we finally
got enough off to toss into the furnace. When the furnace hit around
1500 degree, the shop teacher realized that our block of aluminum was
really a block of magnesium 8-). We like to have NEVER got it
extinguished. It put out a really cool looking greenish-yellow flame
too. And no one thought to bring the winnies 8-).