Copying an eccentric bushing
 

I'm trying to repair a partly stripped spare headstock for a South
Bend Heavy 10, as shown on page 2 of this:
http://www.neme-s.org/Shaper%20Books...s%20Manual.pdf

I haven't figured out how to make the back gear lever K+J, which moves
the eccentrically-located quill shaft in or out of engagement with the
spindle gears. My lathe is 30 years older than that manual and the
spare probably older still, and they don't appear to have a separate
bushing J, the lever and the eccentric bushing look like a single
casting. The shaft is taper-pinned to the eccentric bushings at both
ends so the shaft and bushings rotate together.

I got as far as drilling oversized round stock to fit on the shaft but
now I don't see how to attach the blank for K to O to turn the outer
bearing surface concentric and then move it to the far end of the
shaft without losing rotational alignment. To complicate the problem
the OD at J is 1.250" while O's is 1.625".

It would be easy if I cut key slots in the shaft, K and O, locking
them together while turning J and preserving the angular alignment
when I move K+J to the far end. Can you think of a method that uses
the original hard-to-find SB shaft and part O without damaging them?
jsw

Copying an eccentric bushing
 

On 5/23/2013 3:39 PM, Jim Wilkins wrote:
I'm trying to repair a partly stripped spare headstock for a South
Bend Heavy 10, as shown on page 2 of this:
http://www.neme-s.org/Shaper%20Books...s%20Manual.pdf

I haven't figured out how to make the back gear lever K+J, which moves
the eccentrically-located quill shaft in or out of engagement with the
spindle gears. My lathe is 30 years older than that manual and the
spare probably older still, and they don't appear to have a separate
bushing J, the lever and the eccentric bushing look like a single
casting. The shaft is taper-pinned to the eccentric bushings at both
ends so the shaft and bushings rotate together.

I got as far as drilling oversized round stock to fit on the shaft but
now I don't see how to attach the blank for K to O to turn the outer
bearing surface concentric and then move it to the far end of the
shaft without losing rotational alignment. To complicate the problem
the OD at J is 1.250" while O's is 1.625".

It would be easy if I cut key slots in the shaft, K and O, locking
them together while turning J and preserving the angular alignment
when I move K+J to the far end. Can you think of a method that uses
the original hard-to-find SB shaft and part O without damaging them?
jsw


The exploded drawing seems to be showing only the right-hand end of the
shaft is raised to disengage the small gear. The left-hand end is always
engaged. And the lever and left-hand bushing are a single casting, as
you wrote.

I wonder if someone else has repaired the machine and pinned an
eccentric bushing at both ends, so both gears are disengaged?

Paul

Copying an eccentric bushing
 

"Paul Drahn" wrote in message
...
On 5/23/2013 3:39 PM, Jim Wilkins wrote:
I'm trying to repair a partly stripped spare headstock for a South
Bend Heavy 10, as shown on page 2 of this:
http://www.neme-s.org/Shaper%20Books...s%20Manual.pdf


The exploded drawing seems to be showing only the right-hand end of
the shaft is raised to disengage the small gear. The left-hand end
is always engaged. And the lever and left-hand bushing are a single
casting, as you wrote.

I wonder if someone else has repaired the machine and pinned an
eccentric bushing at both ends, so both gears are disengaged?

Paul

The drawing on page 2 doesn't show the shape of the parts accurately.
Both end bushings are eccentrically bored to the same offset and
pinned to the shaft with #2 taper pins, parts 91 and 102 on page 15,
which shows the eccentricity more clearly. Shaft 94 is 0.748" diameter
its full length except for grease grooves. The *** for 92 and 93 on
page 16 indicates that the 10" model doesn't use them.

On my working lathe the backgear shaft remains parallel to the spindle
as the lever K swings it in or out of engagement. I'd loan K+J from
the good lathe to the spare as needed if the taper pin holes aligned,
but they are shifted by almost the pin's diameter on the spare
headstock.

I bought the spare headstock to make a large diameter wheel and pulley
lathe, with the tool bit on an X-Y table that's manually aligned
parallel to the faceplate so it won't require precision ways, just a
rigid frame. It will definitely need working back gears.

jsw

Copying an eccentric bushing
 

On Thu, 23 May 2013 18:39:21 -0400, "Jim Wilkins"
wrote:

I'm trying to repair a partly stripped spare headstock for a South
Bend Heavy 10, as shown on page 2 of this:
http://www.neme-s.org/Shaper%20Books...s%20Manual.pdf

I haven't figured out how to make the back gear lever K+J, which moves
the eccentrically-located quill shaft in or out of engagement with the
spindle gears. My lathe is 30 years older than that manual and the
spare probably older still, and they don't appear to have a separate
bushing J, the lever and the eccentric bushing look like a single
casting. The shaft is taper-pinned to the eccentric bushings at both
ends so the shaft and bushings rotate together.

I got as far as drilling oversized round stock to fit on the shaft but
now I don't see how to attach the blank for K to O to turn the outer
bearing surface concentric and then move it to the far end of the
shaft without losing rotational alignment. To complicate the problem
the OD at J is 1.250" while O's is 1.625".

It would be easy if I cut key slots in the shaft, K and O, locking
them together while turning J and preserving the angular alignment
when I move K+J to the far end. Can you think of a method that uses
the original hard-to-find SB shaft and part O without damaging them?
jsw

Greetings Jim,
If it was me I would first turn the O.D. of each eccentric. I would
then drill an undersized hole at the taper pin location. I would then
put a pin in this hole and use it to locate one axis of the eccentric
hole. Then I would bore the eccentric holes. Finally I would ream the
holes for the proper fit for the taper pin. I would the inspect the
original shaft the bushings go on and make sure that both taper pins
line up with each other and with the same axis as the eccentric. I
would then correct any holes that were in the wrong place. In fact,
the shaft should be done first so that you know on which axis of the
eccentric bushings the pin should go. Also, do you have the proper
taper pin reamer(s)?
Eric

Copying an eccentric bushing
 

wrote in message
...
On Thu, 23 May 2013 18:39:21 -0400, "Jim Wilkins"
wrote:

I'm trying to repair a partly stripped spare headstock for a South
Bend Heavy 10, as shown on page 2 of this:
http://www.neme-s.org/Shaper%20Books...s%20Manual.pdf


Greetings Jim,
If it was me I would first turn the O.D. of each eccentric. I would
then drill an undersized hole at the taper pin location. I would
then
put a pin in this hole and use it to locate one axis of the
eccentric
hole. Then I would bore the eccentric holes. Finally I would ream
the
holes for the proper fit for the taper pin. I would the inspect the
original shaft the bushings go on and make sure that both taper pins
line up with each other and with the same axis as the eccentric. I
would then correct any holes that were in the wrong place. In fact,
the shaft should be done first so that you know on which axis of the
eccentric bushings the pin should go. Also, do you have the proper
taper pin reamer(s)?
Eric

I have larger and smaller taper pin reamers but not #2. There isn't
much stress between the handle and shaft since its engaged and
disengaged stops are in a slot cut into the handle's bearing surface
and the friction shoe that keeps the gears engaged while cutting rides
against the other bushing O. I was planning to clamp part K onto the
shaft with a brass-tipped setscrew, possibly the handle itself, to
avoid butchering an original SB part. People collect and restore these
things.

Keeping both bushings on the same rotational axis both when turning
part K while it's somehow clamped to O and then when attaching it to
the end of the shaft is what I haven't figured out, but I got an idea
using vee blocks and 3/16" shims while writing this.
jsw

Copying an eccentric bushing
 

On May 23, 5:39*pm, "Jim Wilkins" wrote:
I'm trying to repair a partly stripped spare headstock for a South
Bend Heavy 10, as shown on page 2 of this:http://www.neme-s.org/Shaper%20Books...8%20Parts%20Ma...

I haven't figured out how to make the back gear lever K+J, which moves
the eccentrically-located quill shaft in or out of engagement with the
spindle gears. My lathe is 30 years older than that manual and the
spare probably older still, and they don't appear to have a separate
bushing J, the lever and the eccentric bushing look like a single
casting. The shaft is taper-pinned to the eccentric bushings at both
ends so the shaft and bushings rotate together.

I got as far as drilling oversized round stock to fit on the shaft but
now I don't see how to attach the blank for K to O to turn the outer
bearing surface concentric and then move it to the far end of the
shaft without losing rotational alignment. To complicate the problem
the OD at J is 1.250" while O's is 1.625".

It would be easy if I cut key slots in the shaft, K and O, locking
them together while turning J and preserving the angular alignment
when I move K+J to the far end. Can you think of a method that uses
the original hard-to-find SB shaft and part O without damaging them?
jsw

If you measure the distance "off center" for the eccentric, maybe you
can machine the bushing in a 4 jaw chuck with the bushing fastened to
a stub that is set with the same eccentricity. You could make two
eccentric bushings with different diameters. Assuming that the pins
in the shaft are in the same plane, the new eccentric bushings should
be aligned too.

Copying an eccentric bushing
 

Jim Wilkins wrote:
I'm trying to repair a partly stripped spare headstock for a South
Bend Heavy 10, as shown on page 2 of this:
http://www.neme-s.org/Shaper%20Books...s%20Manual.pdf

I haven't figured out how to make the back gear lever K+J, which moves
the eccentrically-located quill shaft in or out of engagement with the
spindle gears. My lathe is 30 years older than that manual and the
spare probably older still, and they don't appear to have a separate
bushing J, the lever and the eccentric bushing look like a single
casting. The shaft is taper-pinned to the eccentric bushings at both
ends so the shaft and bushings rotate together.

I got as far as drilling oversized round stock to fit on the shaft but
now I don't see how to attach the blank for K to O to turn the outer
bearing surface concentric and then move it to the far end of the
shaft without losing rotational alignment. To complicate the problem
the OD at J is 1.250" while O's is 1.625".

It would be easy if I cut key slots in the shaft, K and O, locking
them together while turning J and preserving the angular alignment
when I move K+J to the far end. Can you think of a method that uses
the original hard-to-find SB shaft and part O without damaging them?
jsw



Why not make it all as new parts instead of trying to work on the old ones?

Turn THREE eccentrics, then align drill/ream the pin holes. Now mill
your slot in one of those. Remove the slotted bushing and stack it on a
suitable section of shafting with the third eccentric and line them up.
Make witness marks and pull them apart, now bore holes foe a pair of
dowel pins on the adjoining faces. Turn a suitable handle and mill a
flat on the outer bushing and weld the handle on. Drill and tap for a
set screw to hold the piece to the shaft with the dowels fully seated.


--
Steve W.

Copying an eccentric bushing
 

"Steve W." wrote in message
...
Jim Wilkins wrote:
I'm trying to repair a partly stripped spare headstock for a South
Bend Heavy 10, as shown on page 2 of this:
http://www.neme-s.org/Shaper%20Books...s%20Manual.pdf


Why not make it all as new parts instead of trying to work on the
old ones?

Turn THREE eccentrics, then align drill/ream the pin holes. Now mill
your slot in one of those. Remove the slotted bushing and stack it
on a suitable section of shafting with the third eccentric and line
them up.
Make witness marks and pull them apart, now bore holes foe a pair of
dowel pins on the adjoining faces. Turn a suitable handle and mill a
flat on the outer bushing and weld the handle on. Drill and tap for
a set screw to hold the piece to the shaft with the dowels fully
seated.
Steve W.

That is essentially my fallback position if I don't find a way to
angularly align the new handle bushing on the existing shaft.

The small end of the #2 taper pin in "O" is 0.160" diameter so I can
use a 1/8" or 5/32" roll pin to attach the new handle and maybe ream
for a taper pin later.

I do have broaches to cut keyways to connect and align a new non-SB
replacement shaft and bushings, and the eccentricity is low enough to
drill offset center holes in the ends of the new shaft and turn it and
the keyed-on bushings as a unit, like a built-up crankshaft. The main
problem there is drilling both end's centers at the same angular
position.
jsw