I am trying to get a chuck to mount on my G9972Z 11x26 lathe. After
using thread wires, I think 1 3/4 x 8 tpi is pretty damn close.

To me, the measurements look like the bolt holes more or less incline
towards the outside of the chuck .035 to .050, then we expect the poor
mounting bolt to flex back a bit to meet the adapter plate's bolt
circle. This chuck is supposed to adjust akin to a Set-Tru, yet the
mounting bolt heads are an interference fit against the outer edge of
the counterbore. It does not move about the hub when the bolts are
started. Perhaps I am too perfectionist, but this is not what I expect
of a US made chuck.

//---------------- My note to the manufacturer ------------//

Chuck and plate arrived. Chuck and plate mounting holes do not appear to
be aligned close enough to allow unimpeded operation of _adjustment_
function, adapter plate will not screw on spindle past @ three threads.

Issues: Socket head mounting boltheads are at outer edge of counterbore
in chuck face. Individual adapter plate mounting bolt hole threads are
good, all tapped holes allow you to screw in the bolts using your
fingers. When you try to mount the chuck to the adapter plate, some
bolts take a hex wrench to start. The four adjustment set screws are not
in contact with hub and are still within chuck body.

Hole pairs measured with center points, from hole center to hole center.
Hole pairs are not matched.

Chuck Chuck Adapter
(Top) (Bottom)
4.454 4.487 4.470
4.451 4.504 4.470
4.454 4.484 4.468

From the measurements, the bolt circle at the top of the chuck is @
4.501+, the bolt circle at the bottom of the chuck is 4.485+, and the
adapter bolt circle is 4.470-.

Adapter plate screws onto spindle from either side about three threads,
then stops. At first glance, the spindle threads are pretty close to 1
3/4 x 8 tpi.

On 3/3/2010 14:36, Louis Ohland wrote:

Chuck Chuck Adapter
(Top) (Bottom)
4.454 4.487 4.470
4.451 4.504 4.470
4.454 4.484 4.468

From the measurements, the bolt circle at the top of the chuck is @
4.501+, the bolt circle at the bottom of the chuck is 4.485+, and the
adapter bolt circle is 4.470-.

Bolt circle at top of chuck is _4.451+_, not 4.501 (dyslexia)

On 2010-03-03, Louis Ohland wrote:
I am trying to get a chuck to mount on my G9972Z 11x26 lathe. After
using thread wires, I think 1 3/4 x 8 tpi is pretty damn close.

Hmm ... the Grizzley is made in China so it is more likely to be
a metric thread. Converting 8 tpi to metric comes out as 3.18mm pitch,
so could it be either 3.00 mm or 3.25 mm (or perhaps 3.20 mm).

I believe that the only one of these which is actually imperial
threads as sold is the Jet -- in which the original threads are turned
off the spindle, a sleeve heat shrunk onto it, and the imperial thread
is turned on the spindle sleeve using the thread gearing of the actual
lathe so it is possible to cut the spindle thread into a blank
backplate.

To me, the measurements look like the bolt holes more or less incline
towards the outside of the chuck .035 to .050, then we expect the poor
mounting bolt to flex back a bit to meet the adapter plate's bolt
circle. This chuck is supposed to adjust akin to a Set-Tru, yet the
mounting bolt heads are an interference fit against the outer edge of
the counterbore. It does not move about the hub when the bolts are
started. Perhaps I am too perfectionist, but this is not what I expect
of a US made chuck.

Who made the chuck? If it came with the Grizzley, it is likely
not US made -- just as the Grizzley is not US made.

Dimensions converted to metric in your table below.

Chuck Chuck Adapter
(Top) (Bottom)
4.454 113.13mm 4.487 113.97mm 4.470 113.54mm
4.451 113.06mm 4.504 114.40mm 4.470 113.54mm
4.454 113.13mm 4.484 113.89mm 4.468 113.49mm

From the measurements, the bolt circle at the top of the chuck is @
4.501+, the bolt circle at the bottom of the chuck is 4.485+, and the
adapter bolt circle is 4.470-.

Hmm ... 113mm, 114mm and 113.5mm would be the metric figures,
which seem to make a bit more sense -- though they are still wrong for
the task.

Adapter plate screws onto spindle from either side about three threads,
then stops. At first glance, the spindle threads are pretty close to 1
3/4 x 8 tpi.

Almost certainly a metric spindle thread. Do you have a set of
metric thread pitch gauges? The diameter (1-3/4) works out as about
44.45mm, and the thread pitch as 3.18mm (likely 3.2mm).

Hmm ... the downloadable spec sheet does *say* 1-3/4 x 8, but
I'm not sure that I trust it.

It does say "Country of origin: China", and they list the
following chucks:

5" 3-Jaw Chuck with Two Sets of Jaws
6-1/2" 4-Jaw Chuck with Reversible Jaws

Are these the ones in question, or did you get a chuck from another
source?

O.K. The manual also says 1-3/4x8 spindle. So, perhaps the
problem is in the chuck backplate.

Good Luck,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

Who made the chuck? If it came with the Grizzley, it is likely
not US made -- just as the Grizzley is not US made.

The chuck is to replace the original chuck. I asked the manufacturer if
it was US made, he said it was. I am not divulging the maker at this point.

Almost certainly a metric spindle thread. Do you have a set of
metric thread pitch gauges? The diameter (1-3/4) works out as about
44.45mm, and the thread pitch as 3.18mm (likely 3.2mm).

Uh, I hope that a pitch gauge refers to a number of leaves with the
thread teeth stamped out. I only have Imperial. If an 8tpi drops in
pretty damn close, what will using a metric pitch gauge do?

I think finding an M45x3 nut will be the cheapest way to determine the
actual thread... Comments?

Hmm ... the downloadable spec sheet does *say* 1-3/4 x 8, but
I'm not sure that I trust it.

http://www.ibmmuseum.com/OhlandL/lathe/G9972Z_fm.pdf

This is the original owner's manual. If you look, there are two listed
spindle threads right next to each other, M45x3 and 1 3/4 x 8.


It does say "Country of origin: China", and they list the
following chucks:

5" 3-Jaw Chuck with Two Sets of Jaws
6-1/2" 4-Jaw Chuck with Reversible Jaws

Are these the ones in question, or did you get a chuck from another
source?

A 5" from another source.


O.K. The manual also says 1-3/4x8 spindle. So, perhaps the
problem is in the chuck backplate.

Is it normal for the bolt hole centers in the chuck to start at 4.451 on
top, expand to 4.487 on the chuck bottom, then back to 4.470 on the
adapter plate? Sort of makes me wonder how well the adjustment feature
will work when the mounting bolts are already against the outside of the
counterbore...

On 2010-03-04, Louis Ohland wrote:

Who made the chuck? If it came with the Grizzley, it is likely
not US made -- just as the Grizzley is not US made.

The chuck is to replace the original chuck. I asked the manufacturer if
it was US made, he said it was. I am not divulging the maker at this point.

O.K. Was the backplate by the same maker?

Almost certainly a metric spindle thread. Do you have a set of
metric thread pitch gauges? The diameter (1-3/4) works out as about
44.45mm, and the thread pitch as 3.18mm (likely 3.2mm).

Uh, I hope that a pitch gauge refers to a number of leaves with the
thread teeth stamped out.

Yes, it does.

I only have Imperial. If an 8tpi drops in
pretty damn close, what will using a metric pitch gauge do?

How close is "pretty damn close"? If you see light around it
(other than at the roots and crests where there is likely extra
clearance on the gauge for various styles of crest and root), then it is
not a perfect fit. If you can rock the blade a bit from end to end it
is not a prefect fit. Only if it is rock steady in the thread is it a
perfect fit.

So -- using a metric pitch gauge would let you feel for whether
the fit is better or worse.

I think finding an M45x3 nut will be the cheapest way to determine the
actual thread... Comments?

I was at first wondering whether it was a standard thread or
not. it appears to be the metric fine thread in that size.

And looking in the MSC on-line search the closest that I find is
the coarse metric thread M45x4.5 -- and just to put it in perspective,
that one sells for $45.09 *each* -- and it is not the one which you
want to use -- the fine thread is less common, and thus more expensive.
Lots of metal in a nut of that size anyway.

In contrast, a combination thread pitch gage -- both metric and
imperial -- which will handle a M3.00 pitch as well as 8 TPI costs
$11.32 ea in the same catalog. That one is item #84395755.

Hmm ... the downloadable spec sheet does *say* 1-3/4 x 8, but
I'm not sure that I trust it.

http://www.ibmmuseum.com/OhlandL/lathe/G9972Z_fm.pdf

This is the original owner's manual. If you look, there are two listed
spindle threads right next to each other, M45x3 and 1 3/4 x 8.

Interesting! Depending on how the '/' in several of the entries
is to be interpreted, it seems that the shorter bed has the metric
spindle thread, and the longer one has the imperial -- *maybe*.

Anyway -- the two threads are similar, but not identical - and
for the length of needed thread engagement, they do need to be
identical.


It does say "Country of origin: China", and they list the
following chucks:

5" 3-Jaw Chuck with Two Sets of Jaws
6-1/2" 4-Jaw Chuck with Reversible Jaws

Are these the ones in question, or did you get a chuck from another
source?

A 5" from another source.

O.K.

O.K. The manual also says 1-3/4x8 spindle. So, perhaps the
problem is in the chuck backplate.

Is it normal for the bolt hole centers in the chuck to start at 4.451 on
top, expand to 4.487 on the chuck bottom, then back to 4.470 on the
adapter plate?

First off -- the adaptor plate has to be considered separately,
as it may have been made for a different chuck, or a different model in
this maker's chucks.

As for the difference between the center spacing at the jaw and
the backplate sides -- that is a sign that the mount which held the
chuck was not perpendicular to the drill press spindle.

Then again -- how exactly did you measure the center distances?
If you measured using digital calipers zeroed inside one hole and then
measuring between two holes (a good enough way to measure that) there is
one consideration. Can the inside jaws reach deep enough to actually
measure the bore -- or were you measuring at the counterbore on one end?
If so, that counterbore may not be truly concentric with the through
hole.

Sort of makes me wonder how well the adjustment feature
will work when the mounting bolts are already against the outside of the
counterbore...

Presumably, this is the kind with long bolts through the chuck
body, with a counterbore at the jaw end so it can be tightened and
loosened while holding a workpiece so you can zero it? Anyway -- you
need the through hole to be loose enough to allow the offset -- and can
probably live with a bit of tilt to the holes. But the holes in the
backplate into which they thread do need to be within the range of the
loose fit of the bolts in the chuck body.

Good Luck,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

Got a reply from the chuck manufacturer (they made the chuck and adapter
plate). They want me to return it. The bolt circles ain't raaht.

I measured the bolt hole spacing with a pair of centerline points and
was able to reach the bolt hole passage inside the counterbore on top.

When my first attempts to assemble the chuck and plate didn't pan out, I
started to measure the bolt circles. Remember Sesame Street, "this one
is like the others, this one doesn't belong"?

The thread gauge was rock steady. It had full contact on all teeth, top
to bottom.

I do have the longer bed lathe, the Zangzhou Supermachine Company Bench
Lathe CQ6128A×660 http://www.yangzhoumachine.com/e-cp-7.htm shows a
550mm as well. Does not even mention spindle thread.

Funny, one of the messages on the home page was "Our Pinnacle: Customer
is Our God", you don't see that every day.


On 3/4/2010 22:56, DoN. Nichols wrote:
On 2010-03-04, Louis wrote:

Who made the chuck? If it came with the Grizzley, it is likely
not US made -- just as the Grizzley is not US made.

The chuck is to replace the original chuck. I asked the manufacturer if
it was US made, he said it was. I am not divulging the maker at this point.

O.K. Was the backplate by the same maker?

Almost certainly a metric spindle thread. Do you have a set of
metric thread pitch gauges? The diameter (1-3/4) works out as about
44.45mm, and the thread pitch as 3.18mm (likely 3.2mm).

Uh, I hope that a pitch gauge refers to a number of leaves with the
thread teeth stamped out.

Yes, it does.

I only have Imperial. If an 8tpi drops in
pretty damn close, what will using a metric pitch gauge do?

How close is "pretty damn close"? If you see light around it
(other than at the roots and crests where there is likely extra
clearance on the gauge for various styles of crest and root), then it is
not a perfect fit. If you can rock the blade a bit from end to end it
is not a prefect fit. Only if it is rock steady in the thread is it a
perfect fit.

So -- using a metric pitch gauge would let you feel for whether
the fit is better or worse.

I think finding an M45x3 nut will be the cheapest way to determine the
actual thread... Comments?

I was at first wondering whether it was a standard thread or
not. it appears to be the metric fine thread in that size.

And looking in the MSC on-line search the closest that I find is
the coarse metric thread M45x4.5 -- and just to put it in perspective,
that one sells for $45.09 *each* -- and it is not the one which you
want to use -- the fine thread is less common, and thus more expensive.
Lots of metal in a nut of that size anyway.

In contrast, a combination thread pitch gage -- both metric and
imperial -- which will handle a M3.00 pitch as well as 8 TPI costs
$11.32 ea in the same catalog. That one is item #84395755.

Hmm ... the downloadable spec sheet does *say* 1-3/4 x 8, but
I'm not sure that I trust it.

http://www.ibmmuseum.com/OhlandL/lathe/G9972Z_fm.pdf

This is the original owner's manual. If you look, there are two listed
spindle threads right next to each other, M45x3 and 1 3/4 x 8.

Interesting! Depending on how the '/' in several of the entries
is to be interpreted, it seems that the shorter bed has the metric
spindle thread, and the longer one has the imperial -- *maybe*.

Anyway -- the two threads are similar, but not identical - and
for the length of needed thread engagement, they do need to be
identical.


It does say "Country of origin: China", and they list the
following chucks:

5" 3-Jaw Chuck with Two Sets of Jaws
6-1/2" 4-Jaw Chuck with Reversible Jaws

Are these the ones in question, or did you get a chuck from another
source?

A 5" from another source.

O.K.

O.K. The manual also says 1-3/4x8 spindle. So, perhaps the
problem is in the chuck backplate.

Is it normal for the bolt hole centers in the chuck to start at 4.451 on
top, expand to 4.487 on the chuck bottom, then back to 4.470 on the
adapter plate?

First off -- the adaptor plate has to be considered separately,
as it may have been made for a different chuck, or a different model in
this maker's chucks.

As for the difference between the center spacing at the jaw and
the backplate sides -- that is a sign that the mount which held the
chuck was not perpendicular to the drill press spindle.

Then again -- how exactly did you measure the center distances?
If you measured using digital calipers zeroed inside one hole and then
measuring between two holes (a good enough way to measure that) there is
one consideration. Can the inside jaws reach deep enough to actually
measure the bore -- or were you measuring at the counterbore on one end?
If so, that counterbore may not be truly concentric with the through
hole.

Sort of makes me wonder how well the adjustment feature
will work when the mounting bolts are already against the outside of the
counterbore...

Presumably, this is the kind with long bolts through the chuck
body, with a counterbore at the jaw end so it can be tightened and
loosened while holding a workpiece so you can zero it? Anyway -- you
need the through hole to be loose enough to allow the offset -- and can
probably live with a bit of tilt to the holes. But the holes in the
backplate into which they thread do need to be within the range of the
loose fit of the bolts in the chuck body.

Good Luck,
DoN.

On 2010-03-05, Louis Ohland wrote:
Got a reply from the chuck manufacturer (they made the chuck and adapter
plate). They want me to return it. The bolt circles ain't raaht.

O.K. If all from the same maker, yes it is certain that they
are not right -- not just that the backplate was designed for a
different chuck.

I measured the bolt hole spacing with a pair of centerline points and
was able to reach the bolt hole passage inside the counterbore on top.

O.K. Good enough.

When my first attempts to assemble the chuck and plate didn't pan out, I
started to measure the bolt circles. Remember Sesame Street, "this one
is like the others, this one doesn't belong"?

Actually -- I was too old to watch it when Sesame Street
started, and never had kids to watch it with.

The thread gauge was rock steady. It had full contact on all teeth, top
to bottom.

O.K. Good enough -- but this still leaves the question of why
it is behaving like a slight thread pitch mismatch (the three turns and
stop is typical of that). Did you mention that to them as well?
Perhaps the backplate has the metric thread instead of the spindle.

And you probably should also try measuring the pitch diameter of
the spindle thread. Do you have a set of thread pitch diameter
measuring wires? If so, look up the right ones to use for 8 TPI, and
measure over the wires and apply the correction from the information
sheet with the wire set -- or look it up in _Machinery's Handbook_,
which will also tell you how to calculate the right correction factor
for wires which are close but not quite the supplied size for 8 TPI.

I do have the longer bed lathe, the Zangzhou Supermachine Company Bench
Lathe CQ6128A×660 http://www.yangzhoumachine.com/e-cp-7.htm shows a
550mm as well. Does not even mention spindle thread.

Interesting .

Funny, one of the messages on the home page was "Our Pinnacle: Customer
is Our God", you don't see that every day.

And if they treat you right, then this suggests that this is the
truth. (Or is this the lathe maker, not the chuck?)

Good Luck,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---