According to William Wixon :
hey don,
thanks for your detailed response. my responses/further questions
below...
took a photo of the "saddle"/"carriage" and uploaded it...
http://www.frontiernet.net/~wwixon/handles.jpg
O.K. This will help greatly. (Though I must admit that I
missed the mention of the image the first time through and I was quite
puzzled at the references to numbers until I got to the bottom and the
image URL was mentioned again.
"DoN. Nichols" wrote in message
...
[ ... ]
Actually -- no. The longitudinal feed is in the same direction
that the half-nuts move the carriage -- but much slower, giving finer
feed (and a nicer finish), and reducing wear on the leadscrew to save it
purely for threading.
wow, i REALLY don't understand that. i've used a lathe before but just
don't konw what the parts are called. the lathe i used (and this lathe) i
can move the tool holder/"saddle" side to side along teh ways with the
handle "1" (rapidly and imprecicely)
This is what I was calling the "handwheel". It normally is a
steel or cast iron wheel with a polished rim and a crank handle sticking
out at one point only. The wheel is easier to use for fine control, and
the crank for coarse control.
or move the tool holder/"saddle" slowly
(but precicely) with teh long screw under the ways (assuming that's called
the lead screw).
That is the leadscrew (or at least the main "threading"
leadscrew). There are two others within the range of what you have
photographed -- one which achieves the "cross feed", and is turned by
the crank you have labeled "6". The other moves the "compound" (the
section which can be set at different angles), and that one is turned by
the crank which you label "5". The crank on that one frequently has two
crank handles, allowing you to achieve fine motion by the thumb on one
and the index finger on the other.
are you saying the handle that moves teh saddle rapidly
but imprecicely is called the longitudinal feed?
No -- it moves the carriage in the longitudinal direction.
The leadscrew and half nuts moves the carriage much more rapidly
and precisely in the same direction -- and should be used only for
threading -- assuming that you have a true longitudinal feed in your
apron. I am using the term "longitudinal feed" as a term for a
capability, not a control. More on this a bit later. (If I don't
forget. :-)
when the half nuts are
engaged (they're engaged onto the lead screw) it moves the carriage slowly.
i don't get what you're saying at all.
It moves the carriage fairly rapidly -- depending on how fast
the leadscrew is rotating. This is changed by the gears between the
spindle and the leadscrew (and by a quick-change gearbox in a lathe with
is recent enough).
What you have described is called the cross-feed, which is
usually present on a lathe which also has the longitudinal feed.
thanks. "cross feed"
Crank "6" is the cross-feed crank. However (as you have
discovered) it can be driven by gearing in the apron, and this is
typically quite slow, and we can call that "power cross feed" to avoid
confusion with the function of the crank itself.
Typically, there is a lever or clutch which will engage either, and
select either. I've seen lathes with two clutch levers, one for
i think maybe knob "2" is a clutch.
It looks right to be a clutch.
[ ... ]
Half nuts are typically engaged by moving a lever to the right
side of the apron to a down position, at which point the carriage will
move fairly fast (depending on the threading gearing).
there is a replacement part made of aluminum "4" that engages the half nut
(or what appears to me to be a nut sliced in half, so i figure that must be
a half nut)
It is. I suspect that this once had a longer name, such as
"half nut coupling" or something similar, and it got shortened by use
habits.
(this replacement part, i was impressed by whoever made it,
seemed like a somewhat complicated piece of mill work.) i'm a little
worried though, seems to me that it weighs enough/is loose enough that it
can flop down and engage itself. i'm trying to figure out a way to hook up
a spring or bungee or something to prevent it from flopping down and
engaging the half nut "without my permission".
Hmm ... there *should* be a notch in a part of it inside the
apron into which a spring-loaded ball or something similar is pressed to
keep the half-nuts from engaging volutarily. You will probably need to
take the apron apart -- and possibly put up more photos for us to
analyze -- to figure this out.
[ ... ]
Sometimes, there is a star wheel which allows you to gradually engage
the clutch, and allows it to slip if necessary.
could the star wheel be "2"?
Yes. Not a star in this case -- though the South Bend manual
will probably show one.
Identify the half-nut lever and the handwheel which moves the
i got the half nut lever and the carriage hand wheel... and have been
fiddling with them, but am afraid to advance any furhter. (and as i
mentioned, the carraige hand wheel is VERY stiff, jerky, rough.)
I *think* that you are being fought by the "longitudinal power
feed". Your part "3" looks like a selector to choose between (power)
cross feed and (power) longitudinal feed. You say that it flops around
as well? I would expect detents in it to avoid accidentally engaging
the half-nuts and the longitudinal feed at the same time -- just from
vibration of the lathe as it cuts.
And I would expect it to have a center position in which it does
not engage either the power cross feed or the power longitudinal feed.
When the power longitudinal feed is enaged (and the leadscrew is
turning) it should turn the handwheel "1" to move the carriage slowly
along the bed. This may be engaged, and may be what you are fighting.
carriage. Everything else is most likely longitudinal and cross feed.
And as long as you don't have the half-nuts engaged, you can play with
the others with no problems (as long as you stop them before the
carriage reaches the chuck or the tailstock. :-)
last night i tried engaging the lead screw and moving the carriage left to
right under power, which was fun. moved surprisingly slowly. then i
changed the direction of the leadscrew (with teh handle on the headstock)
and it seemed like the motion was rough, maybe as if something was being
FORCED, didn't like that and so stopped doing it. seemed as if the gears in
the headstock, when they were configured to move the opposite way, didn't
like it at all.
Hmm ... a problem in the tumbler gears (which are what do the
reversing). It looks as though those are hidden under a plate to which
your other threading gears mount, based on the photo with the flash
stopping the spokes of the big pulley. You'll need to pull that apart
and see what is happening in there. The typical design is that when the
reversing lever is in the forward position, a single gear picks up the
rotation of the spindle. When it is in the reverse position, a second
gear is moved between the first and the spindle gear, effecting the
reverse motion. It *may* be that this gear is stripped, or that things
simply need better lubrication.
Or -- it might be that something in the apron and carriage are
fighting motion in the reverse direction.
And -- it might be that your cross/longitudinal selector "3" is
bouncing out of mesh.
For smooth power feed motion you need:
1) the half nuts disengaged (tie that lever up to be safe, until
you can install a detent of some sort.
2) The cross/longitudinal selector "3" in position and prevented from
accidentally disengaging. (You mentioned a nut to lock it?).
3) The clutch screwed in to pick off motion from the leadscrew
(it probably has a long keyway cut through the threads the whole
length -- this rotates a worm gear in the apron, and the clutch
couples this rotation to whichever power feed you have selected
by "3".
For *threading*, you need:
1) The cross/longitudinal selector "3" locked into a neutral
position.
2) The clutch "2" disengaged, so it is not rotating anything inside
the apron.
3) The half nuts selector lever pushed down to engage the half
nuts during a threading pass, and lifted up to disengage it.
It *should* stay in *whichever* position you put it in. In
particular, you don't want it to drop back into engaged position
when you are cranking the cross feed out to prepare for another
pass. If this does not stay, you have serious problems, and
this should be fixed in some way.
It will tell you how South Bend lathes do this. They are
somewhat different from my Clausing, and yet again different from a
Sheldon ...
thanks.
But -- it will at least tell you what kind of behavior to
expect.
Interesting. Disengage the feed to the leadscrew (the reversing
lever on the headstock should have a neutral position), and then you can
i've had the lever in the neutral position, afraid to engage the lead screw
drive.
play with the controls without damaging anything -- but also without it
doing anything useful.
chuckle (i went to art school, this project has been for me at least
partially a creative expression/outlet, hope though this lathe won't end up
being entirely a kinetic sculpture.)
:-)
The handwheel? This may imply that you have a longitudinal feed
i wouldn't have thought it would be called a handwheel. what in the heck is
it called now, the word excapes me now, not a lever, not a knob, "handle",
what's it called? do they refer to this thing as a handwheel even though
there's no "wheel" component to it? "crank"?
It is where the handwheel *should* be in a later machine, and
serves the function of a handwheel. It is just too early a machine to
have an actual wheel. :-) Your South Bend manual will show you real
handwheels. :-)
lever engaged with the clutch set to allow you to override it by enough
oh! is the longitudinal feel lever the thing on the headstock that makes
the lead screw rotate?!
No -- that is the reverse tumbler lever. There is no
longitudinal feed *lever*. The longitudinal feed function is selected
by a combination of the selector "3" and the clutch "4".
You really need to talk to the other person on here who has a
Star, and ask him just how those are expected to behave on your machine.
If I were there, I would be experimenting and finding out what it is
doing, what it *should* be doing and is not, and how to make it do what
it should do.
hand force.
Are you sure? This may be why you are having strange behavior.
it seemed as if there were enough of a tooth remaining on each of the broken
teeth to uninterruptedly engage the mating gear.
You mean that the teeth were not broken all the way across?
It is possible to build up where broken teeth were with screws
and brazing compound, and then to file them into the shape of gear teeth
again -- with very careful work and test fitting against a mating gear.
Good Luck,
DoN.
in my photo...
http://www.frontiernet.net/~wwixon/handles.jpg
"1" moves the carriage from left to right/right to left. (is very stiff
and jerky. i think the pinion gear might need to be shimmed or something, i
think maybe it's too tightly crammed up into the "rack" gear under the
bed/ways. is that what they're called, "rack and pinion"?)
The rack gear, with a worn carriage on a worn bed which are
re-scraped to a good fit will wind up with the pinion too *low* and at
that time a shim mounted between the rack gear and the lathe bed is used
to move it down far enough to engage. This kind of work also probably
requires moving the leadscrew down a little to keep it lined up with the
half nuts and the worm gear in the apron.
My first thought is that you are fighting the longitudinal feed
function (selected by "3"). Can you lock that lever in an in-between
position, where it engages neither the longitudinal feed nor the
cross-feed? (This is where we need someone who knows how *your* lathe
is supposed to behave.
"2" seems to be a clutch that makes "6" turn but i think it also makes "1"
turn too,
It should, depending on the position of "3".
not sure what "2" does. screw it in, tightens up and engages
something inside, turn it the opposite way and loosens, disengages whatever
it was it engaged.
"2" is the clutch. All the way out (loosened) should make it
fairly easy to crank the carriage from end to end -- unless you have a
lock clamp engaged on the carriage.
"3" flops up and down from position "a." to position "b.", tighten the knob
to make it stay at either position. (i'm very confused as to what this
handle does.)
The "knob" is under the lever in 3?
In any case, this *should* -- at least on a normal lathe --
select the power feed (through the clutch "2") to go to the cross-feed
(crank "6"), or to the handwheel (crank "1"). And it *should* have a
middle position where it will drive neither of those -- even with the
clutch engaged.
Can the knob under lever "3" be set just stiff enough so you can
move the lever "3" from cross-feed to longitudinal-feed positions, or
leave it in the middle and drive nothing?
"4" engages/disengages the, i assume, "half nut".
It is in the right place to do so, so that is pretty likely.
The problem here is your missing detent, so it can drop into engaged
position without your agreement.
Later lathes have an interlock which keeps you from engaging
both the half nuts and the longitudinal feed at the same time.
According to Jim, his does not have that. I keep wondering whether it
was simply a part which wore out or got left out when the apron was
apart some time..
"5" what do you guys call that one? transverse feed?
The "compound" crank.
"6" moves the tool holder toward or away from the operator. this handle
will rotate under power of the lathe.
The "crossfeed" crank.
I wish that I were in a position to take a look at this in
person. There is an awful lot which would be quicker with my hands on
the machine to check out what is happening -- especially since it is a m
machine which I have never handled -- working or not.
Good Luck
DoN.
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