i just received a jet jml-1014 mini-lathe as an early Christmas present, i
have
noticed the pens i have turned are oval and off center. i can feel vibration
on the piece as i turn it, it seems like the shaft is off center, the hand
wheel also is rotating off center. i
have cleaned the taper, tried different mandrels, different live centers. i
do not have a dial indicator yet so i cannot say how far things are off but
i would guess around 1/16-1/32 inch on the right end of the shaft and around
1/8 inch or more on the hand wheel end. anybody have any suggestions as to
what the problem could be? i am going to call jet tomorrow morning but i am
looking for advise before i call.

http://www.hopkinsonline.net

jeremy wrote:
(clip) would guess around 1/16-1/32 inch on the right end of the shaft and
around 1/8 inch or more on the hand wheel end. (clip)
^^^^^^^^^^^
Runout in the handwheel may not be important, unless it originates in the
spindle. Your problem could be due to spindle runout. When you refer to
1/16 to 1/32 runout, how are you judging it? I recommend you bring your
toolrest up very close, and turn the lathe slowly by hand.

Another test I would try is to insert the pen mandrel, and leave the
tailstock end free. Turn the lathe by hand, and see whether the free end
"orbits." If it does not, you problem is probably due to excessive
tailstock pressure, as has been suggested by Chuck. If it does, it could be
a curved mandrel, or a bad spindle. To determine which it is, turn the
mandrel 180 degrees in the spindle, and see whether the runout at the end of
the mandrel changes sides.

Or, if you have a drill bit with a Morse taper shank, insert that, and see
whether it runs true.

On Wed, 17 Dec 2003 01:28:51 -0500, "Jeremy Hopkins"
wrote:

i just received a jet jml-1014 mini-lathe as an early Christmas present, i
have
noticed the pens i have turned are oval and off center. i can feel vibration
on the piece as i turn it, it seems like the shaft is off center, the hand
wheel also is rotating off center. i
have cleaned the taper, tried different mandrels, different live centers. i
do not have a dial indicator yet so i cannot say how far things are off but
i would guess around 1/16-1/32 inch on the right end of the shaft and around
1/8 inch or more on the hand wheel end. anybody have any suggestions as to
what the problem could be? i am going to call jet tomorrow morning but i am
looking for advise before i call.

Is your tailstock staying tight while you turn pens? Check to make
sure that the set screw is engaging the groove on the back side of the
quill.

Have you snugged it up to the mandrel, __but not too tight__? If you
put too much pressure on the pen mandrel, it will cause it to bow, and
make your pens go oval. You only need to tighten it up enough so it
makes the bearings in the live center engage. Also, are you using the
correct bushing for the model of pen you are turning?

To see if the tailstock is out of alignment, push the tailstock up to
the headstock and see if the pins in the drive center and the live
center line up with each other.

Finally, make sure you have the belt on the appropriate wheel, ie. the
one that is directly above and below one another, rather than crossed
over. I suppose it's possible that this could make the motor vibrate.

That's about all I can think of at the moment...give those a try. I'm
going out and turn on mine in a few minutes.


--
Chuck *#:^)
chaz3913(AT)yahoo(DOT)com
Anti-spam sig: please remove "NO SPAM" from e-mail address to reply.


September 11, 2001 - Never Forget


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Thanks for the replies,
I am strongly suspecting a bad spindle,i think the handwheel runout is
coming from the spindle.I tried a new mandrel and it did "orbit", i borrowed
a #2mt drill bit and it "orbited" too! the local jet warranty center is
going to take care of the problem tomorrow.
"Leo Lichtman" wrote in message
...

jeremy wrote:
(clip) would guess around 1/16-1/32 inch on the right end of the shaft and
around 1/8 inch or more on the hand wheel end. (clip)
^^^^^^^^^^^
Runout in the handwheel may not be important, unless it originates in the
spindle. Your problem could be due to spindle runout. When you refer to
1/16 to 1/32 runout, how are you judging it? I recommend you bring your
toolrest up very close, and turn the lathe slowly by hand.

Another test I would try is to insert the pen mandrel, and leave the
tailstock end free. Turn the lathe by hand, and see whether the free end
"orbits." If it does not, you problem is probably due to excessive
tailstock pressure, as has been suggested by Chuck. If it does, it could
be
a curved mandrel, or a bad spindle. To determine which it is, turn the
mandrel 180 degrees in the spindle, and see whether the runout at the end
of
the mandrel changes sides.

Or, if you have a drill bit with a Morse taper shank, insert that, and see
whether it runs true.

Jeremy Hopkins wrote:

noticed the pens i have turned are oval and off center. i can feel

Wow, I gotta get some sleep. After that other thread, I mis-read this one.
I was thinking it was strange you had a brand new lathe, and your first
project was turning a penis.

(Following the thread with interest, but unable to contribute anything
useful. SWMBO still has my JET mini is still stashed in Mom's closet
somewhere. It's a feminine conspiracy I tell ya!)

--
Michael McIntyre ---- Silvan
Linux fanatic, and certified Geek; registered Linux user #243621
http://www.geocities.com/Paris/Rue/5407/