On 2007-11-27, Jon Elson wrote:
DoN. Nichols wrote:
[ ... ]
Hmm ... HP made a nice front-loading self-threading tape drive
(which we had with the Solbournes), which was SCSI interface. And I've
[ ... ]
There were two front-loading 9-track drives. i don't think
either of them were very good, but the Digi-Data was certainly
one of the worst things I've ever seen. It could have amazing
disasters during threading, and I suspect any tape in the drive
when it faults or loses power is trash, as it will simply slide
off the hub onto the bottom of the drive when tension is lost.
Ouch! The HP was quite forgiving -- but there were flanges on
the take-up hub in that machine, so it would have been better once it
got threaded.
[ ... ]
I wonder what the technology which It used was? It looked sort
of like a raster scanned photo buildup. Was it wet or dry processed?
Very wet. There was a big bottle of toner, which had something
like laser toner suspended in some kind of solvent that smelled
a little like paint thinner, a little like gasoline. Just
writing about it, I can smell the stuff now! Yucck!
O.K. Glad that I didn't try for one at the on-post surplus
sales. For all I know, it came from the computer center where I used it
that once -- but since it was a mainframe, I had to use it at a
distance. :-)
[ ... ]
Now, if I could just find a good laser printer which could print
on a roll of paper, I would be happy. :-)
Yes, that was the ONE advantage of the Versatec, but the rest of
it was a DIS-advantage.
Just as it is the one advantage of a drum plotter which I have.
Resolution is 0.010", almost direct drive of stepper motors from the
computer, something like a 15 V input signal, even though it was low
current. It required a special wire-wrapped interface from my SWTP
6809.
The advantage of that roll paper feed was that I could directly
plot the fret positions for a stringed instrument.
[ ... ]
Maybe or maybe not. Solaris is supposed to be a real-time OS to
start with, and with a PCI version of the Servo-To-Go card it should be
possible to bring it up on any of the Ultra systems (which all have PCI
slots instead of Sbus.)
There IS no PCI version of the Servo-to-Go card. Strictly ISA,
and thus woefully obsolete.
So I see after visiting their web site. There is simply the
original (which I have) and the second version, which is still ISA.
My hardware runs on an IEEE-1284
capable parallel port. Is the real time compatible with rtai?
RTAI? What is that? The later Suns (including my SB-1000s)
have a fully programmable parallel port, once you find the right termio
signals to send to the driver. I would Google for RTAI, but the time is
getting too close to go to the CAMS (Chesapeake Area Metalworking
Society) meeting here in Virginia. (Alternate months are in VA and MD,
and only the VA one is close enough to be really reasonable with a SUV
which takes lots of fuel to carry the show-and-tell metalworking things
to the meeting. :-)
I've been sort of considering trying that with
my Bridgeport. (The linux seems to not be stable with my current
hardware, and I've never finished the conversion of the machine -- which
started life as a Bridgeport Series-I BOSS-3 running on an old quad-wide
LSI-11. The system had a massive case of electronic Altzheimer's, and
would forget what it was doing within fifteen seconds of being reset.
Usually, that was not enough time to load a tiny progrma to test it. :-)
Bridgeport never got the hang of cooling electronics, all their
gear cooked chips. They also built their own, very bad, power
supplies. I know garage hardware hackers who have no formal
training in electronics who build MUCH better gear than the old
BOSS systems. Not a whole lot of LSI-11's around that still work.
O.K. I've got three of them -- but the rest of the system
locked up regularly. Actually -- the only time it behaved normally was
when it was too hot in the shop for *me* to work without drowning the
machine is salty sweat. :-(
I've been converting the controller to EMC based, and the
steppers to servo motors, with one serious hangup. The servos are a lot
longer than the original steppers.
That is a common issue.
The Y-axis stepper fit into a recess
in the knee, and the servo can't fit. I've got to build an alternate
motor mount/belt guard which slopes at a 45 degree angle down to the
right, so the motor winds up beside the knee instead of trying to stab
through the knee's jackscrew. :-) And to do this properly, I really need
welding capability -- which I do not yet have. Or I need to get the
motor mount assembly from a later Bridgeport -- from after *they* moved
to servos.
I need some of the same parts. I have a 1938 round-ram
Bridgeport that I converted to CNC, but it still has the short
knee from those days. I pcked up a later BOSS knee and saddle
that have been stripped, and have been accumulating bits for it,
to eventually put it on the old machine. I found a new Y
ballscrew on eBay, but haven't come up with an X screw, yet.
Do you know that the X-axis ballscrew does not turn? It is
rigidly mounted to the right-hand end of the table, and the ball *nut* is
what is turned between two matched bearings. The advantages a
1) The leadscrew cannot whip with a quick move.
2) The ball screw cover is simpler -- a telescoping flat spring
wound around the ballscrew.
And do you have the Series-I head for the CNC version? The ball
screw for that is hollow -- surrounding the quill, with the ball nut
rotating around that, so the thrust is truly on axis.
And, I need all the bearing mounts/belt housings, etc.
Not a big rush, as it still has a lot of scraping to do before
it is ready to go on.
Just as I don't have a great hurry here. I've got a nice
Nichols horizontal mill with a vertical head which works nicely for
manual milling.
Enjoy,
DoN.
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