Hi Arch, where have you been ?? kind of missed you on the rcw.
Arch wrote:
Not the first or last, but here are a few things that I assumed I knew
something about til I realized that I didn't. Wonder if y'all have a few
of your own?
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1. The MT2 in the end of a 1" or 1.25" spindle doesn't leave much
meat. Does inserting a dummy MT2 when using a faceplate or heavy chuck
on a heavy load help significantly? Please _ignore RPM.
Just depending here as always, shaft thickness between bearings and
length, length of overhang, but filling the shaft with a fitting taper
will certainly increase the stiffness of that shaft, MO
2. Does pounding a blank into a spur center on the lathe or driving the
tail center hard against the blank harm the bearings? I think the front
bearing race acts as the register for my N3K and pounding would hurt the
bearing. Not sure about lathes that use collars, etc. or separate
registers to prevent axial motion of the spindle? Also not sure if the
N3K's bearing race being tightened against the head casting is the cause
of the 'braking effect' of over tightening the tail center?
Bearings and bearings are like wood and wood, all kinds and not the
same, there are many configurations and/or combinations of bearings,
not to mention qualities.
However if the right kind of bearing of good quality is used I wouldn't
be afraid to wallop a chunk of wood onto a spur center wood, the steel
will win that handily.
Now running the lathe while HEAVY pressure is put upon them is another
story, we have now steel wearing against steel, and the lubrication
film could very well be insufficient and overheating and damage could
then occur, so yes you can use pressure, but if the bearings heat up a
lot, take some pressure off and/or slow down. MO
3. When the headstock end of a long heavy blank held with tail support
is balanced with counterweights adjusted on a steel plate, is the entire
length of the long blank now in balance. (ie. do I need to balance both
ends of a long heavy blank?)
Like Leo L said, you might have static balance, but that's not dynamic
balance, to which I would like to add, that if you have rigged up a
piece of wood and got it statically balanced and you now think you can
rev. it up, the dynamics are there in full force, and you better be
aware of that, it can do a lot of damage in a hurry, so keep it down.
3. Is the N3K's revolving headstock any less prone to vibration when
locked down along the bed axis than when at an angle to the bed? This
concerns the headstock _only. Please _ignore tail support or the
stability or instability of the bench & floor.
I'm not to sure about this one Arch, vibration is more like a
resonance, and probably a dynamically induced imbalance, changing with
speeds used, I don't think rotating the headstock will, but could make
a difference, like I said I'm not sure.
4. Is a Jarno taper used on a Jacob's chuck arbor because it's short or
there other reasons? Which best prevents mating parts from rotating, MT
or JT? I've had both tapers slip by deliberately overstressing cheap
chucks. I let them rust to prevent slipping. Is there a better way to
'tighten' Morse & Jarno tapers?
This is more a thing of who got the upper hand in making drill bits
and the drill chucks, with their own proprietary taper, best way to
prevent slippage is a clean and precise fit, MO
5. If it's a practical truth and not a logical myth that hi carbon steel
makes better scrapers than hi speed steel, then why wouldn't cold rolled
steel flats make even better scrapers? Probably like the three bears,
the middle is just right.
I don't follow you here Arch, the metal crystal structure and the kind
of other alloys/metals in there make for the carbon steel to generally
be able to be sharpened to a finer/narrow edge, This to the best of my
knowledge. I worked with it, never made it.
6. May not matter, but does my N3K's VS DC motor & its controls want me
to use its speed pot or the run switch or the line switch for the
frequents stops & starts during a long turning session? (please _ignore
the advantages of ramping up or down. that's not the question) Does it
hurt anything but my light bill to leave both line and run switches on
and the speed pot turned to zero?
Haven't got a clue Arch, maybe it's something like what hurts most, I
hit it or it hits me.
I bet the answers are obvious to someone here, but they sure aren't to
me. 
Turn to Safety, Arch
Fortiter
http://community.webtv.net/almcc/MacsMusings