In article ,
jim rozen wrote:
In article , DoN. Nichols says...
http://www.metalworking.com/DropBox/Seneca_Lathe_1.jpg
http://www.metalworking.com/DropBox/Seneca_Lathe_2.jpg
Hmm ... I would like to see a more detailed close-up of the
apron. Don't e-mail it to me, because I'm blocking anything over 30k to
keep the spam out, but another upload to the dropbox would be nice.
Looking at it, I *think* that the four-pointed star wheel is a
friction clutch to power feed. And I think that the power feed is only
longitudinal, as I don't see a control to switch it to the cross-feed.
OK, here's one:
http://www.metalworking.com/DropBox/_2000_retired_files/Seneca2.jpg
O.K. Thanks.
I'm not sure which of these has already been posted, but for the record:
http://www.metalworking.com/DropBox/_2000_retired_files/Seneca1.jpg
http://www.metalworking.com/DropBox/_2000_retired_files/Seneca3.jpg
http://www.metalworking.com/DropBox/_2000_retired_files/Seneca4.jpg
and
http://www.metalworking.com/DropBox/_2000_retired_files/Seneca.txt
The four-pointed knob is of course the feed clutch as you suspected,
DoN. The half nuts lever protrudes out of the far right side of
the apron - there is actually a square slot on the side to allow
this.
The control that allows one to switch from longitudinal feed to
crossfeed is a stud that protrudes out the front of the apron,
on the lower right corner which is a sort of wing nut where the
wings are turned as round spheres. (the reversing tumbler
adjustment also sports one of these)
Aha! I was wondering about this. I noticed the lever which
runs the half-nuts and wondered whether that was it. And given that, it
would make the stud some form of control for the power feeds.
The adjustment rides up and down in a slot in the apron front,
so one loosens the knob, and lifts or drops the wingnut handle,
and then re-tightens it in the correct place. His lathe has
those nuts with a very large diameter base so they pretty
much hide the slot. Also in his photo showing the apron, I
think it's in the "up" position. In my photo it's definitely
"down" and the base of the nut is small, so it would be easy
to see the slot, except the crossfeed handle is partly
obscuring it.
Yep! And on his, I think that there is too much paint, so it is
obscuring some of the functionality of the controls.
I can only detect *one* sylistic difference between mine and
his, and that is the handle for the tailstock ram clamp.
Note also that you still have the dabber for the white lead well
to lubricate tailstock centers where they engage the center hole of the
workpiece. His is missing. Perhaps that could now be used to store the
key for the tailstock drill chuck.
Mine had seen some rough use, somebody engaged the back gears
while running and stripped off a couple of teeth. THere is
a serviceable repair in place. Also the lead screw support
on the right side was at one time ripped off the machine,
another serviceable repair is in place there. More about that
monenarilly.
Ouch!
[ ... ]
Back to the leadscrew bracket repair on this machine. It is
apparent after using it briefly that the apron has NO
lockout that prevents one from simultaneously engaging the
longitudinal feed and the half nuts. All modern machines
have this lockout, because if one does engage them both
at the same time, it effectively locks the lead screw,
because the two drive ratios are different.
Hmm ... looking at where the power feed lever is located, I
could see the possibility of a slot in a partial disc rotated by it,
especially if the power feed lever could be placed in a central position
which engages neither power feed. If so, then a projection on the half
nuts themselves, or on the lever could allow it to move only if the
power feed is in a neutral position. And -- if that projection is made
of cast iron along with the half-nuts engagement lever, it might be
fragile enough so a determined pull on the half nuts lever by an
insufficiently trained operator might break that projection off, thus
allowing simultaneous engagement of both feeds.
In my lathes case, somebody did this, and the drive
from the spindle gear ripped the right-hand side bracket
right off the machine at that point. So anyone with
a lathe like this should be fore-warned to avoid accidentally
doing that while the machine is in actual use.
Perhaps he can check to see whether there *is* a lockout for the
half-nuts when the power feeds is engaged on his. Yours may have been
destroyed at the same time that the leadscrew bracket was damaged.
Have you taken the apron apart to study the parts? Look for a
sign of a broken part of the cast iron. If the setup is as I suspect
that it might be, it would also prevent the power feeds from being
engaged when the half-nuts were enaged.
Let's see what I can do with ASCII graphics. As usual, view
with a fixed pitch font like Courier:
_________________
/ |
/ +-----+ _____
/ | __ |
/ +-----+ | |
/ ^ | | |
/ (1) | | |
|(x) v | | |
+------------------------+ | | possible weak point
_________| \_______________________ ^
((x) | |
\____________________________________+ v
The "(x)" are pivot points.
The "(1)" is where the stud for the feed direction control
connects.
The long projection to the right is the half-nuts engagement
lever (without showing how the engagement actually is driven to
keep the ASCII drawing simple. Same for details of the power
feed linkage. :-)
It is shown with both levers in the (supposed) neutral
positions.
If the power feed direction control is either up or down, the
slot is not in position to allow the projection from the
half-nuts lever to drop into it.
If the Half nuts lever is engaged, the slot is not free to be
moved up or down.
Thus an interlock -- until a determined tug on the half-nuts
lever breaks the projection at the indicated weak point.
Oh, there's one more dropbox photo, forgot about this one,
a bit blurry:
http://www.metalworking.com/DropBox/_1998_retired_files/jim6.jpg
Still useful.
Check out the possibility that something like what I drew could
have been part of the original design. I find it difficult to imagine
anything but a prototype being made without an interlock, even way back
when -- though it certainly is possible.
Thanks,
DoN.
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