I am having a problem that I I need some advice about. My Nova 3000 doesn't
seem to be turning things round. If I turn a pen, and get the blank down to
the bushing on one side of say the nib end it will be sticking out on the
other side. If make a box the mating ends will be flush on one side and the
top will protrude slightly on the other side. I am probably not explaining
myself very well but it seems as though I am turning an eccentric circle
instead of a proper circle. I checked the run out on the headstock with my
dial guage and there is a 3/1000th difference. Is this enough to cause this
problem or is there something wrong with my technique? Thanks for the help.

John Broadway
Kamloops BC

John Broadway wrote:
I am having a problem that I I need some advice about. My Nova 3000 doesn't
seem to be turning things round. If I turn a pen, and get the blank down to
the bushing on one side of say the nib end it will be sticking out on the
other side. If make a box the mating ends will be flush on one side and the
top will protrude slightly on the other side. I am probably not explaining
myself very well but it seems as though I am turning an eccentric circle
instead of a proper circle. I checked the run out on the headstock with my
dial guage and there is a 3/1000th difference. Is this enough to cause this
problem or is there something wrong with my technique? Thanks for the help.

As far as the pen goes, you may be turning it round, but not centered on the
insert. Is the pen mandrel straight? The long rod on the pen mandrels are
easy to bend. measure the rubout at various points along the mandrel.

mike

John, put a drive center in the headstock and a live center in the tailstock
and bring them to almost touching. Is there a horizontal difference? (front
to back of the lathe). Your headstock is adjustable so release the locking
mechanism and grab whatever will give you some leverage and move the head
until the center points line up. Re-tighten while watching if the alignment
changes.
Anytime you move/pivot the head you should do this little exercise to assure
that the centers are lined up when you bring the head back to "normal"
position. And always retighten the pivot lock. Just snug.
"John Broadway" wrote in message
news:P1t4d.76911$%S.5491@pd7tw2no...
I am having a problem that I I need some advice about. My Nova 3000
doesn't
seem to be turning things round. If I turn a pen, and get the blank down
to
the bushing on one side of say the nib end it will be sticking out on the
other side. If make a box the mating ends will be flush on one side and
the
top will protrude slightly on the other side. I am probably not
explaining
myself very well but it seems as though I am turning an eccentric circle
instead of a proper circle. I checked the run out on the headstock with
my
dial guage and there is a 3/1000th difference. Is this enough to cause
this
problem or is there something wrong with my technique? Thanks for the
help.

John Broadway
Kamloops BC

On Thu, 23 Sep 2004 08:30:34 -0400, "Jim Pugh"
wrote:

damn, Jim... that's too easy!

As a returning turner, I've forgotten so many basic things like that
after years of not having room for my shop.. thanks for refreshing my
memory, I'll check that alignment tonight!

John, put a drive center in the headstock and a live center in the tailstock
and bring them to almost touching. Is there a horizontal difference? (front
to back of the lathe). Your headstock is adjustable so release the locking
mechanism and grab whatever will give you some leverage and move the head
until the center points line up. Re-tighten while watching if the alignment
changes.
Anytime you move/pivot the head you should do this little exercise to assure
that the centers are lined up when you bring the head back to "normal"
position. And always retighten the pivot lock. Just snug.
"John Broadway" wrote in message
news:P1t4d.76911$%S.5491@pd7tw2no...
I am having a problem that I I need some advice about. My Nova 3000
doesn't
seem to be turning things round. If I turn a pen, and get the blank down
to
the bushing on one side of say the nib end it will be sticking out on the
other side. If make a box the mating ends will be flush on one side and
the
top will protrude slightly on the other side. I am probably not
explaining
myself very well but it seems as though I am turning an eccentric circle
instead of a proper circle. I checked the run out on the headstock with
my
dial guage and there is a 3/1000th difference. Is this enough to cause
this
problem or is there something wrong with my technique? Thanks for the
help.

John Broadway
Kamloops BC






Mac

Either the plank is not centered, which I doubt if you do not have trouble
with other items, the mandrel is bent or your hole is not perfectly
straight. If your drilled hole is off to one side the results will be what
you are experiencing.

Tim

"John Broadway" wrote in message
news:P1t4d.76911$%S.5491@pd7tw2no...
I am having a problem that I I need some advice about. My Nova 3000
doesn't
seem to be turning things round. If I turn a pen, and get the blank down
to
the bushing on one side of say the nib end it will be sticking out on the
other side. If make a box the mating ends will be flush on one side and
the
top will protrude slightly on the other side. I am probably not
explaining
myself very well but it seems as though I am turning an eccentric circle
instead of a proper circle. I checked the run out on the headstock with
my
dial guage and there is a 3/1000th difference. Is this enough to cause
this
problem or is there something wrong with my technique? Thanks for the
help.

John Broadway
Kamloops BC

I missed the beggining of this thread so appologise if I have misunderstood
the question, and my contribution has nothing to do with the 'problem'.
Whilst the truer the lathe runs (least runout) the better it is, this is not
going to prevent an object from being turned truly round. After all, in
ofset turning, an item could be several inches off centre and still be
turned perfecly round, so a few 'thou' runout is certainly not going to stop
this from happening.

If the tailstock centre is not perfectly inline with the headstock it also
is not going to prevent a parallel piece from being turned. Afterall unlike
a metal lathe the toolrest travel is not kept in fixed alignment to both the
headstock and the taistock. In woodturning, we move the toolrest/banjo as we
wish, with no need to maintain any particular reference to the centres, only
to the work. Close as possible without letting the timber hit the rest.

The most concern I would have with headstock/ mainshaft runout, is that it
could cause vibration. This would become more severe as the speed increased.
This would make it unpleasant to use the lathe and could even lead to
producing a rippled effect while cutting. However this (rippled /corrugated
surface) can even be caused by lack tool sharpness and technique.

My first lathe had a fairly obvious vibration (mainly caused by motor/
pulley errors) but I persevered and still could turn objects round. However
if I had not experienced it myself I probably would not have believed how
much better it was to turn on a lathe that did not vibrate. And how much
easier it was to produce better finish on my work. (Unfortunately it did not
make it more artistic :-( )

Cheers, Peter Stacey
---------------------------

"Anonymous" wrote in message
newsan.2004.10.12.02.37.45.614257@notarealserver .com...
On Thu, 23 Sep 2004 05:19:43 +0000, John Broadway wrote:

I checked the run
out on the headstock with my dial guage and there is a 3/1000th
difference. Is this enough to cause this problem or is there something
wrong with my technique? Thanks for the help.

John Broadway
Kamloops BC

Since you didn't tell us how bad the run-out is at the far end, it's tough
for us to do the trig and see if this accounts for the error.
SNIP If this closely approximates the error you are observing, you've
found the culprit.

As a point of interest, I keep reading very good things about your model
of lathe, but given the price of that lathe, .003 run-out seems like an
awful lot. I would expect the run-out to be more on the order of .0003 --
but that might be because I haven't completely changed over from the
expectations of a machinist.

Bill

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What he's saying is that runout is immaterial _between_ centers. Wood is
compressible enough to take up a lot of difference. Non-spindles are
another matter. There the unconfined end is free to wander, and you to
chase it.

Peter's example is of a standard turning trick, where _both_ centers are
moved on the same vector for the same distance. This produces an oval
turning.

Your example is also a technique used by yours truly on his mushrooms, so a
cap parallel to the "ground" can sit on a slanted stem. Sometimes I use
both, so I have an oval cap.

If you're turning bowls, you'll want to clear the problem of runout or
compensate with faceplate mountings trued each time.

"Anonymous" wrote in message
newsan.2004.10.13.21.52.25.24461@notarealserver. com...
On Wed, 13 Oct 2004 09:52:03 +1000, L. Peter Stacey wrote:

I missed the beggining of this thread so appologise if I have
misunderstood the question, and my contribution has nothing to do with
the
'problem'. Whilst the truer the lathe runs (least runout) the better it
is, this is not going to prevent an object from being turned truly
round.
After all, in ofset turning, an item could be several inches off centre
and still be turned perfecly round, so a few 'thou' runout is certainly
not going to stop this from happening.

With all due deference, I believe you are mistaken. Turn a dowel shape
(round & parallel) in a piece of stock at least 6" long. Wipe it with
contrasting stain (no need to wait for it to dry). Now offset the
tailstock by a small amount. Recut the piece. If you move your cutting
tool parallel to the centerline of the lathe until you just barely clean
up up to the midpoint of the spindle, I think you'll find that one end is
a cone and the other is lopsided.

If you can follow a spindle that is wobbling around the centerline (rather
than revolving around it) and cut it both round and parallel, you are a
far better turner than I.

Bill

PS: Being a better turner than I is not that big of a challenge.

--
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"Anonymous" wrote in message
newsan.2004.10.13.21.52.25.24461@notarealserver. com...
On Wed, 13 Oct 2004 09:52:03 +1000, L. Peter Stacey wrote:

SNIP
With all due deference, I believe you are mistaken. Turn a dowel shape
(round & parallel) in a piece of stock at least 6" long. Wipe it with
contrasting stain (no need to wait for it to dry). Now offset the
tailstock by a small amount. Recut the piece. If you move your cutting
tool parallel to the centerline of the lathe until you just barely clean
up up to the midpoint of the spindle, I think you'll find that one end is
a cone and the other is lopsided.
---------------------------------------
"Anonymous" I entirely aggree with you on this point
"If you move your cutting tool parallel to the centerline of the lathe"
However, seeing that there is no reason to restrict oneself to having the
cutting tool travel parallel with the centreline of the lathe, (after all,
is this not the way most spindle turning is shaped?) there is nothing to
stop one from turning a true parallel dowel irrespective of how far the
tailstock may be out of line. Like the exact oposite of turning a taper, on
a lathe that has the tailstock in perfect alignment?
All that needs to be done is to move the tool /toolrest to be parallel to
the centreline of the WORK, NOT the BED.
Cheers from 'Down Under' Peter Stacey.
---------------------------------------------
If you can follow a spindle that is wobbling around the centerline (rather
than revolving around it) and cut it both round and parallel, you are a
far better turner than I.

Bill

PS: Being a better turner than I is not that big of a challenge.

--
http://cannaday.us (genealogy)
http://organic-earth.com (organic gardening)
Uptimes below for the machines that created / host these sites.
17:25:01 up 64 days, 5 min, 4 users, load average: 0.02, 0.14, 0.12
17:10:00 up 161 days, 1:11, 3 users, load average: 0.00, 0.00, 0.00