According to Joseph Gwinn :
In article ,
(DoN. Nichols) wrote:
[ ... ]
And while I have had my motor apart -- the bearing at the pulley
end did not want to come out of the housing, and I did not want to try
too hard while I was working on other things.
I assume it is designed to allow removal at least.
Yes -- but something is wedged I think. What I'll need to do is
to thread a chunk of mild steel to protect the threads for the pulley
securing nut and then try pressing (and driving) it out -- once I have
spare bearings on hand.
[ ... ]
Right -- but you can change the business end with the screw-on
"chuck" just as easily.
True, but replacing the whole spindle is faster, and works even for
holes smaller than the spindle diameter. Quick change seems to be the
issue.
That depends on what you call "the whole spindle". If you mean
from the pulley to the stone mount, I would suggest that the "chuck"
(really a single-size collet" which screws onto the arbor in place of
the normal stone and its end plates (and possible centering adaptors as
well -- as is the case with my stones)) is quicker to screw onto the end
of the spindle than changing the *whole* spindle, involving removing the
pulley, both bearing caps, spacers, and bearings, withdrawing the
spindle, and replacing it with a different spindle with all of the
bearings and such (risking exposing the bearings to grit in the process)
is much more trouble prone than screwing on the "chuck".
I meant the conical thing to which the stone is attached.
O.K. But I still fail to see why that is faster than the
screw-on chuck -- other than not having to unmount the wheel and flanges
and put them aside.
[ ... ]
The one real advantage which I can see to the design implied by
the screw-in ends for the hollow spindles is that a stone can stay
mounted on its arbor, and will not need to be re-trued when it is
re-mounted, if the stone has little enough wear.
I think that's the reason to do it this way. The assembly with bearings
and pulleys seems quite expensive, ~$1,000. I assume (hope) that the
removable part is cheaper. But I don't know that I understand their
pricing structure.
Well ... first off -- the manual for my model of the grinder
puts the price of the spindle at $5.45, and the bearings at $1.95 each.
The chuck assembly is $2.90.
In contrast, the current MSC price for the screw-in spindle ends
ranges from $160.45 to $213.75, while the price for the spindle was
something like $1050.00.
Of course, we don't know the date of that price list. :-)
[ ... ]
Right. Now, Ill have to get a big enough lathe.
O.K. Good luck with that. I've been known to collect
accessories when I could, in hopes of acquiring a machine with which
they could be used later.
But did you inherit a tool that caused lathe acquisition?
Not a chance. The only tools which my father had were a couple
of tiny claw hammers with at least one claw broken off each, two very
rusty screwdrivers, and eventually an electric drill with a circular
sanding pad for work on the boat.
I was the tool user in the family. My father, and his father
were both lawyers (and later, a judge, for my father).
[ ... ]
A bigger issue is how fast the tube deionizes. If it isn't fast enough,
one cannot flash the tube fast enough, as it stops flashing and instead
remains always on. Deionization time is mostly determined by flash tube
design.
This may be one of the reasons for the internal trigger
electrodes, and the extra volume (of unionized xenon) to quickly replace
the ionized stuff.
Exactly. It's the nearby masses of metal that does the job.
That -- and perhaps the greater volume of Xenon surrounding the
arc path?
If it does not deionize quickly enough, and the capacitor
charging current is high enough, it will indeed remain on full time.
Part of the problem is the deionization time, part is the voltage to
which the tube discharges the capacitor.
Edgerton's book "Flash, Strobe" goes into the details of how the
Strobotac and allied devices work.
O.K. Do you have access to that book? I've never seen it --
though I have met and talked to the man. Is it still in print?
I have a question in at Perkin-Elmer asking if the FX-6A is still made,
and if not what is it's replacement (perhaps Series 1100), and what they
cost. We shall see.
O.K. Good luck.
So far, no response.
Sigh!
[ ... "Electric Brazing" ... ]
I saw that one. Never heard of the company.
Nor did I. But it looks like one of the wartime unknowns which
got contracts to make a product known to come from a larger company --
simply because they could not turn them out in the quantities needed.
I've seen Tektronix scope clones made under such contracts -- they
looked almost identical to the Tektronix, other than the maker's name.
Yes. Don't know how good a job they did.
Nor do I -- but they had to match the specs or they would lose
the contract. And they *should* have had copies of the GR prints and
schematics for the purpose. The lack of a large "crystal" dome over the
soupbowl reflector may have been a part of the money-savings and
material savings during wartime.
[ ... ]
O.K. Part of the problem, of course, is stability of the
timebase. A really good one could be made with a crystal oscillator, a
bunch of counter chips and comparators -- load in a count (period, not
frequency) and it would be very stable. Even the nice little GR
Strobotac which I have drifts for the first minute or so. And that one
is solid state. The older (soupbowl) one takes longer to stabilize, and
it is run from tubes.
Yes. The strobe I built is triggered by an optical encoder on the
winder's main axle, so the image stands absolutely still as the rotation
rate is varied.
Any idea what the maximum flash rate was?
[ ... ]
As you already know -- he has scanned them to a higher
resolution, and put them in his private web space.
I got it; looks good.
Yep -- much better than the first pass -- though the first pass
was enough to get me started.
Enjoy,
DoN.
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