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Default Preliminary "test bar" lathe measurements.

I bought a "test bar", which is a 10" or so long with MT3 end.

I inserted centers in the headstock and tailstock and mounted the bar
between those. Then I aligned tailstock with headstock, such that the
position of the indicator was the same at both ends.

This gave me about 6 inches of travel along the straight portion of the
test bar.

The good news is that the travel of the indicator, as I moved the
carriage from one end to another over 6 inches of distance, did not
seem to exceed 0.0003" or so.

Of course, aligning tailstock using position of carriage as a
reference, and them measuring deflection of the indicator on carriage
using the bar as reference, is a little bit "self referential".

In other words, the indicator does not really tell me if the carriage
moves parallel to the imaginary axis of the spindle rotation, because
that axis was not used in any way. But what the indicator does tell
me, is that along those 6 inches, the carriage moves on a straight
line.

That is already something and is much better than what happened with
my old lathe, where the carriage moved along a jumpy line (as
evidenced by abrupt changes in thickness of a test cut).

I will try to do more measurements.

i
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Default Preliminary "test bar" lathe measurements.

On Thu, 28 Jan 2010 22:06:52 -0600, Ignoramus2532
wrote:

In other words, the indicator does not really tell me if the carriage
moves parallel to the imaginary axis of the spindle rotation, because
that axis was not used in any way


Use RDM (Rollie's Dad's Method). Dead simple, and even eliminates
errors in the test bar. The only requirement is that the test bar is
round at the measurement points.
--
RoRo
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Default Preliminary "test bar" lathe measurements.

On Jan 29, 2:06*pm, Ignoramus2532
wrote:
I bought a "test bar", which is a 10" or so long with MT3 end.

I inserted centers in the headstock and tailstock and mounted the bar
between those. Then I aligned tailstock with headstock, such that the
position of the indicator was the same at both ends.


What you have done is align the test bar between the 2 centres. This
will give you accuracy when your turning between centres, but anything
else, ie chuck work, is unknown. You also need to check the spindle
alignment, preferably first, then align the tailstock. As Robert says,
the (Rollie's Dad's Method) method is good, even if a bit hard to
comprehend at first reading.
(I still need to pull my finger out and correct said measured errors
in my humble 9x20...but need to shift so much stuff to be able to get
access to ALL of the headstock bolts that it aint happened. Yet. But
its on the list).
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Default Preliminary "test bar" lathe measurements.

On 2010-01-29, Andrew VK3BFA wrote:
On Jan 29, 2:06?pm, Ignoramus2532
wrote:
I bought a "test bar", which is a 10" or so long with MT3 end.

I inserted centers in the headstock and tailstock and mounted the bar
between those. Then I aligned tailstock with headstock, such that the
position of the indicator was the same at both ends.


What you have done is align the test bar between the 2 centres. This
will give you accuracy when your turning between centres, but anything
else, ie chuck work, is unknown. You also need to check the spindle
alignment, preferably first, then align the tailstock. As Robert says,
the (Rollie's Dad's Method) method is good, even if a bit hard to
comprehend at first reading.
(I still need to pull my finger out and correct said measured errors
in my humble 9x20...but need to shift so much stuff to be able to get
access to ALL of the headstock bolts that it aint happened. Yet. But
its on the list).


Guys, thanks. I loathe to adjust the headstock, because I think that I
will make things worse, not better. Why would headstock be misaligned
on this 43 year old lathe? At this point I just want to
measure bed straightness. Anyway, measuring is easy and fun, and is a
harmless activity, so I will just continue on this part. I have a
longer precision ground shaft, but it is not yet center drilled, and I
wanted to do so accurately.

i
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Default Preliminary "test bar" lathe measurements.

On 2010-01-29, Robert Roland wrote:
On Thu, 28 Jan 2010 22:06:52 -0600, Ignoramus2532
wrote:

In other words, the indicator does not really tell me if the carriage
moves parallel to the imaginary axis of the spindle rotation, because
that axis was not used in any way


Use RDM (Rollie's Dad's Method). Dead simple, and even eliminates
errors in the test bar. The only requirement is that the test bar is
round at the measurement points.


Robert, I read it, it is interesting, but I am left with a
question. What it does not eliminate, is errors in the chuck,
right?

i


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Default Preliminary "test bar" lathe measurements.

On Jan 29, 1:45*pm, Ignoramus7752
wrote:



Guys, thanks. I loathe to adjust the headstock, because I think that I
will make things worse, not better. Why would headstock be misaligned
on this 43 year old lathe?



i

The headstock may never have been aligned really well and every one
during its 43 year life ever was loathe to adjust it.

True story, I bought a nearly new lathe, found that the headstock was
misaligned, and aligned it. Saw the seller a month or so later and
told him that the headstock had been misaligned. His response was
that I should not ever mess with the alignment of the headstock.


Dan
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Default Preliminary "test bar" lathe measurements.

Iggy,
Please find my old response to this procedure. The following sequence is essential.
1) mount test bar into spindle. Spin it to verify it is centered. (no tail stock)
2) use the indicator on the horizontal axis and measure change parallel to the bed by moving the carriage.( Record the readings if
not 0)
3) repeat number 2, but with the indicator on the top of the test bar (vertical axis)
4) if these results are not 0, the head stock must be aligned with the bed with shims. This is very simple to do, but not
necessarily easy. Removing the gear box and drive will be required.

Remember, the most important adjustment is the bed itself. To do this, you must have a precision machine level. This must be done
over a one month period, especially on a large heavy machine. Lathe beds are like a big heavy piece of rubber and they twist very
easily. Follow these steps.
1) level the bed front to back at the head stock end placing the level on the bed at the head stock
2) adjust the bed level head to tail stock with the level on a machine bed flat front or back side doesn't matter.
3) check the bed level front to back at the tail stock end. if the bed is not level there and the bed is still level at the
headstock, you have bed twist.
Be prepared to adjust and readjust through several iterations before you are happy with your findings.

If you have twist, you must counter twist the bed straight. Once that is completed, be prepared to check the set after a few days
and repeat again 'till straight. This can take up to a month to get the set stable. If this is a large machine without a cabinet,
this can be done with the adjustable feet alone. If the lathe bed mounts on a cabinet, remove the bed mounting bolts at the tail
stock end, jack the bed up a bit and shim to suite, until straight. I often drill and tap the bed feet and use a screw to twist
the bed straight, then use feeler gauges to determine the shim size. Then backing off or removing the jacking screws
afterwards.You may note that when measuring for twist that the bed appears to sag in the middle....they do..... it's normal. You
my also find that the bed dynamically twists with the carriage motion....again this is normal. The carriage is front heavy because
of apron weight. My 13 x 40 SB twists.002"in the middle with the carriage centered.
Steve


"Ignoramus2532" wrote in message ...
I bought a "test bar", which is a 10" or so long with MT3 end.

I inserted centers in the headstock and tailstock and mounted the bar
between those. Then I aligned tailstock with headstock, such that the
position of the indicator was the same at both ends.

This gave me about 6 inches of travel along the straight portion of the
test bar.

The good news is that the travel of the indicator, as I moved the
carriage from one end to another over 6 inches of distance, did not
seem to exceed 0.0003" or so.

Of course, aligning tailstock using position of carriage as a
reference, and them measuring deflection of the indicator on carriage
using the bar as reference, is a little bit "self referential".

In other words, the indicator does not really tell me if the carriage
moves parallel to the imaginary axis of the spindle rotation, because
that axis was not used in any way. But what the indicator does tell
me, is that along those 6 inches, the carriage moves on a straight
line.

That is already something and is much better than what happened with
my old lathe, where the carriage moved along a jumpy line (as
evidenced by abrupt changes in thickness of a test cut).

I will try to do more measurements.

i


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Default Preliminary "test bar" lathe measurements.

Shouldn't the testing also include running the DTI along the top or bottom
of the test bar?

And how about running the DTI along a precision tailstock surface, not
associated with the carriage travel?

Just curious.

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html



"Ignoramus2532" wrote in message
...
I bought a "test bar", which is a 10" or so long with MT3 end.

I inserted centers in the headstock and tailstock and mounted the bar
between those. Then I aligned tailstock with headstock, such that the
position of the indicator was the same at both ends.

This gave me about 6 inches of travel along the straight portion of the
test bar.

The good news is that the travel of the indicator, as I moved the
carriage from one end to another over 6 inches of distance, did not
seem to exceed 0.0003" or so.

Of course, aligning tailstock using position of carriage as a
reference, and them measuring deflection of the indicator on carriage
using the bar as reference, is a little bit "self referential".

In other words, the indicator does not really tell me if the carriage
moves parallel to the imaginary axis of the spindle rotation, because
that axis was not used in any way. But what the indicator does tell
me, is that along those 6 inches, the carriage moves on a straight
line.

That is already something and is much better than what happened with
my old lathe, where the carriage moved along a jumpy line (as
evidenced by abrupt changes in thickness of a test cut).

I will try to do more measurements.

i


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Default Preliminary "test bar" lathe measurements.

On 2010-01-29, Wild_Bill wrote:
Shouldn't the testing also include running the DTI along the top or bottom
of the test bar?


Good idea

And how about running the DTI along a precision tailstock surface, not
associated with the carriage travel?


You mean, keep carriage in place and move the tailstock?

i
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Default Preliminary "test bar" lathe measurements.

On Jan 29, 11:33*am, Ignoramus7752
wrote:
On 2010-01-29, Wild_Bill wrote:

Shouldn't the testing also include running the DTI along the top or bottom
of the test bar?


Good idea

And how about running the DTI along a precision tailstock surface, not
associated with the carriage travel?


You mean, keep carriage in place and move the tailstock?

i


Another thing that is extremely important, is to eliminate the
possibility of "bed twist". While it can be fun with a partner, it's
no good when measuring a lathe for accuracy.

You are going to need an accurate Machinist's level.

Level the bed parallel to the ways (axially), then at each end
perpendicular to the ways. You want to make sure that the lathe bed
is level.


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Default Preliminary "test bar" lathe measurements.

What I was wondering about was tracking a tailsock surface with the DTI
secured to the carriage.. longitudinal travel of the carriage, but kinda
limited to one side of the carriage at a time, and only if the tailstock
ways are in nearly perfect condition.

Then again, I don't know if this check would reveal anything significant,
just pondering.

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html


"Ignoramus7752" wrote in message
...
On 2010-01-29, Wild_Bill wrote:
Shouldn't the testing also include running the DTI along the top or
bottom
of the test bar?


Good idea

And how about running the DTI along a precision tailstock surface, not
associated with the carriage travel?


You mean, keep carriage in place and move the tailstock?

i


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Default Preliminary "test bar" lathe measurements.

Kevin, I have been procrastinating about leveling this lathe, but yes,
I should get my act together and start leveling. I do have a machinist
level. It is just a matter of finding 2 hours to do it right.

i
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Default Preliminary "test bar" lathe measurements.

On 2010-01-29, Steve Lusardi wrote:
Iggy,
Please find my old response to this procedure. The following sequence is essential.
1) mount test bar into spindle. Spin it to verify it is centered. (no tail stock)


It is actually not. (!)

I use the Clausing MT4.5 to MT3 taper adapter and this "test bar", and
I find about 0.005" out of center when I set my indicator close to the
end of test bar.

My interpretation of this is that there are some burrs or dirt in the
spindle and that things did not get mounted correctly.

2) use the indicator on the horizontal axis and measure change
parallel to the bed by moving the carriage.( Record the readings if
not 0)


3) repeat number 2, but with the indicator on the top of the test bar (vertical axis)
4) if these results are not 0, the head stock must be aligned with the bed with shims. This is very simple to do, but not
necessarily easy. Removing the gear box and drive will be required.

Remember, the most important adjustment is the bed itself. To do
this, you must have a precision machine level. This must be done
over a one month period, especially on a large heavy machine. Lathe
beds are like a big heavy piece of rubber and they twist very
easily. Follow these steps. 1) level the bed front to back at the
head stock end placing the level on the bed at the head stock 2)
adjust the bed level head to tail stock with the level on a machine
bed flat front or back side doesn't matter. 3) check the bed level
front to back at the tail stock end. if the bed is not level there
and the bed is still level at the headstock, you have bed twist. Be
prepared to adjust and readjust through several iterations before
you are happy with your findings.

If you have twist, you must counter twist the bed straight. Once
that is completed, be prepared to check the set after a few days and
repeat again 'till straight. This can take up to a month to get the
set stable. If this is a large machine without a cabinet, this can
be done with the adjustable feet alone. If the lathe bed mounts on a
cabinet, remove the bed mounting bolts at the tail stock end, jack
the bed up a bit and shim to suite, until straight. I often drill
and tap the bed feet and use a screw to twist the bed straight, then
use feeler gauges to determine the shim size. Then backing off or
removing the jacking screws afterwards.You may note that when
measuring for twist that the bed appears to sag in the
middle....they do..... it's normal. You my also find that the bed
dynamically twists with the carriage motion....again this is
normal. The carriage is front heavy because of apron weight. My 13 x
40 SB twists.002"in the middle with the carriage centered. Steve


Steve... This weekend looks like I will have some time, so I will get
busy leveling.

i

"Ignoramus2532" wrote in message ...
I bought a "test bar", which is a 10" or so long with MT3 end.

I inserted centers in the headstock and tailstock and mounted the bar
between those. Then I aligned tailstock with headstock, such that the
position of the indicator was the same at both ends.

This gave me about 6 inches of travel along the straight portion of the
test bar.

The good news is that the travel of the indicator, as I moved the
carriage from one end to another over 6 inches of distance, did not
seem to exceed 0.0003" or so.

Of course, aligning tailstock using position of carriage as a
reference, and them measuring deflection of the indicator on carriage
using the bar as reference, is a little bit "self referential".

In other words, the indicator does not really tell me if the carriage
moves parallel to the imaginary axis of the spindle rotation, because
that axis was not used in any way. But what the indicator does tell
me, is that along those 6 inches, the carriage moves on a straight
line.

That is already something and is much better than what happened with
my old lathe, where the carriage moved along a jumpy line (as
evidenced by abrupt changes in thickness of a test cut).

I will try to do more measurements.

i


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Default Preliminary "test bar" lathe measurements.

On Fri, 29 Jan 2010 07:49:52 -0600, Ignoramus7752
wrote:

Use RDM (Rollie's Dad's Method). Dead simple, and even eliminates
errors in the test bar. The only requirement is that the test bar is
round at the measurement points.


Robert, I read it, it is interesting, but I am left with a
question. What it does not eliminate, is errors in the chuck,
right?


No, it also eliminates chuck errors, both eccentricity and parallel
errors. The beauty of the method is that it rotates the chuck and
takes two measurements (highest and lowest), and then calculates the
*difference*. Since wobble in the chuck or in the test bar will be
*equal* in size, but *opposite* in direction on each side, it is
eliminated when you calculate the middle.

What the method does not eliminate, are two things: Lack of roundness
of the test bar (on the measuring points) and droop of the test bar
when measuring high/low alignment. The former is easy to eliminate:
Just take a light cut until the cut is contiguous. The latter is more
tricky, unless your machine is small enough to flop in its back while
measuring. Use a thick, stiff test bar to minimize droop. A hollow
test bar may be even better.

Also, you will need to keep the test bar *reasonably* straight and
centered, so that the up/down movement does not cause the indicator to
contact the test bar off center too much. Larger diameter reduces the
problem.

You have probably seen the method described in a "teaspoon" fashion,
including formulas, to make it look massively complicated. In reality,
it is incredibly simple:

1. Chuck your test bar. Don't use the tailstock. Don't worry about
accurate centering; a 3-jaw is fine.
2. Put indicator on the saddle and on the test bar near the chuck and
rotate chuck to find highest and lowest reading, and calculate the
middle (average) between the two.
3. Move saddle far away from chuck without disturbing the indicator
position. Repeat measurement as in point 2.
4. Compare the two results. If they're identical, your spindle and bed
are parallel.
--
RoRo
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Default Preliminary "test bar" lathe measurements.

Ignoramus7752 wrote:

Guys, thanks. I loathe to adjust the headstock, because I think that I
will make things worse, not better. Why would headstock be misaligned
on this 43 year old lathe? At this point I just want to
measure bed straightness. Anyway, measuring is easy and fun, and is a
harmless activity, so I will just continue on this part. I have a
longer precision ground shaft, but it is not yet center drilled, and I
wanted to do so accurately.


Hang on before you start moving the headstock.

Couple of years ago, we moved the prototype machining area and due to management
reorganizing who did what like facility maintenance vs machine maintenance vs assembly
maintenance, the lathe was moved, wired and leveled by facilities.

He, believing it had been leveled properly, figured the taper he was seeing was caused by
the headstock being out so he tweeked it. He figured out shortly that his tail stock and
headstock wasn't on the same axis and asked me to take a look at this thing.

Well, it wasn't leveled worth a damn. Some of the jacks were not holding weight and the
bed was not level and it was twisted. This was a 22 or 23" gap bed swing lathe at least
6' between centers. So I leveled it with a .0005"/ foot set of levels and got it dead
nuts, pressure on all jacks.

The machinist told me he would fix the head stock he screwed with and he did and life for
him was fine once again.

So what is the moral to this story? Have you leveled your bed yet?

Then start measuring things.

Sorry if someone already told you this, I'm catching up on threads right now.

Wes
--
"Additionally as a security officer, I carry a gun to protect
government officials but my life isn't worth protecting at home
in their eyes." Dick Anthony Heller


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Default Preliminary "test bar" lathe measurements.

On Fri, 29 Jan 2010 16:59:13 +0100, "Steve Lusardi"
wrote:

Iggy,
Please find my old response to this procedure. The following sequence is essential.
1) mount test bar into spindle. Spin it to verify it is centered. (no tail stock)
2) use the indicator on the horizontal axis and measure change parallel to the bed by moving the carriage.( Record the readings if
not 0)
3) repeat number 2, but with the indicator on the top of the test bar (vertical axis)
4) if these results are not 0, the head stock must be aligned with the bed with shims. This is very simple to do, but not
necessarily easy. Removing the gear box and drive will be required.

Remember, the most important adjustment is the bed itself. To do this, you must have a precision machine level. This must be done
over a one month period, especially on a large heavy machine. Lathe beds are like a big heavy piece of rubber and they twist very
easily. Follow these steps.
1) level the bed front to back at the head stock end placing the level on the bed at the head stock
2) adjust the bed level head to tail stock with the level on a machine bed flat front or back side doesn't matter.
3) check the bed level front to back at the tail stock end. if the bed is not level there and the bed is still level at the
headstock, you have bed twist.
Be prepared to adjust and readjust through several iterations before you are happy with your findings.

If you have twist, you must counter twist the bed straight. Once that is completed, be prepared to check the set after a few days
and repeat again 'till straight. This can take up to a month to get the set stable. If this is a large machine without a cabinet,
this can be done with the adjustable feet alone. If the lathe bed mounts on a cabinet, remove the bed mounting bolts at the tail
stock end, jack the bed up a bit and shim to suite, until straight. I often drill and tap the bed feet and use a screw to twist
the bed straight, then use feeler gauges to determine the shim size. Then backing off or removing the jacking screws
afterwards.You may note that when measuring for twist that the bed appears to sag in the middle....they do..... it's normal. You
my also find that the bed dynamically twists with the carriage motion....again this is normal. The carriage is front heavy because
of apron weight. My 13 x 40 SB twists.002"in the middle with the carriage centered.
Steve


"Ignoramus2532" wrote in message ...
I bought a "test bar", which is a 10" or so long with MT3 end.

I inserted centers in the headstock and tailstock and mounted the bar
between those. Then I aligned tailstock with headstock, such that the
position of the indicator was the same at both ends.

This gave me about 6 inches of travel along the straight portion of the
test bar.

The good news is that the travel of the indicator, as I moved the
carriage from one end to another over 6 inches of distance, did not
seem to exceed 0.0003" or so.

Of course, aligning tailstock using position of carriage as a
reference, and them measuring deflection of the indicator on carriage
using the bar as reference, is a little bit "self referential".

In other words, the indicator does not really tell me if the carriage
moves parallel to the imaginary axis of the spindle rotation, because
that axis was not used in any way. But what the indicator does tell
me, is that along those 6 inches, the carriage moves on a straight
line.

That is already something and is much better than what happened with
my old lathe, where the carriage moved along a jumpy line (as
evidenced by abrupt changes in thickness of a test cut).

I will try to do more measurements.

i

With precision level lathe alignment a more direct measurement
is to mount the level fore and aft on the cross slide and then
note the CHANGE as the carriage is traversed end to end. This
directly indicates the effect of twist on the tool mount and
also shows up other errors such as sag at mid traverse and wear
or direction sensitive mismating of carriage to vee ways.

If you're chasing tenths, mismatches between the thermal
expansion characteristics of the lathe and its mountings start to
matter. A long time ago I made a bench to carry my Boxford ME10
( slightly uprated 9" Southbend clone). I reasoned that the
bench top should, as nearly as possible, have the same expansion
coefficient AND the same thermal time constant as the lathe bed.

With this in mind I made a sturdy wooden bench topped
with three mighty box section steel girders laid side by side and
welded together. This assembly was comparable in both weight and
torsional stiffness to the Boxford bed.

While this achieved the original aim I hit an unexpected
problem - extreme sensitivity of the hold down bolt adjustment.
Because the welded benchtop was so torsionally stiff, a
fractional thou movement of the bolts resulted in more than a
thou taper turn which made adjustment pretty fiddly. However,
with patience, I got a good result and the setup has remained
nicely stable over several years.

On reflection I realise that the heavy stiff bench top
is the wrong way to go.

There is more than meets the eye in the comparitively flimsy
sheet metal stands supplied by lathe manufacturers. Because the
sheet metal top is torsionally so much less rigid than the lathe
bed a relatively coarse hold down bolt/shim adjustment results in
a usefully fine bed twist adjustment. The thermal time constant
mismatch is of little importance because the resultant bed twist
is a result of the spring force of the deflected metal top and
this is comparitively temperature insensitive.

Jim

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Default Preliminary "test bar" lathe measurements.

On Fri, 29 Jan 2010 07:45:49 -0600, Ignoramus7752
wrote:

On 2010-01-29, Andrew VK3BFA wrote:
On Jan 29, 2:06?pm, Ignoramus2532
wrote:
I bought a "test bar", which is a 10" or so long with MT3 end.

I inserted centers in the headstock and tailstock and mounted the bar
between those. Then I aligned tailstock with headstock, such that the
position of the indicator was the same at both ends.


What you have done is align the test bar between the 2 centres. This
will give you accuracy when your turning between centres, but anything
else, ie chuck work, is unknown. You also need to check the spindle
alignment, preferably first, then align the tailstock. As Robert says,
the (Rollie's Dad's Method) method is good, even if a bit hard to
comprehend at first reading.
(I still need to pull my finger out and correct said measured errors
in my humble 9x20...but need to shift so much stuff to be able to get
access to ALL of the headstock bolts that it aint happened. Yet. But
its on the list).


Guys, thanks. I loathe to adjust the headstock, because I think that I
will make things worse, not better. Why would headstock be misaligned
on this 43 year old lathe? At this point I just want to
measure bed straightness. Anyway, measuring is easy and fun, and is a
harmless activity, so I will just continue on this part. I have a
longer precision ground shaft, but it is not yet center drilled, and I
wanted to do so accurately.

i



The old fashioned method was to mount a piece of stock between centers
and then turn it, full length, with sufficient depth of cut that the
entire diameter was machined. Measure both ends to determine tail
stock offset and adjust. When tail stock alignment is satisfactory
remove faceplate and centers and mount chuck. mount work in chuck with
reasonable overhang and re-machine. Measure head stock misalignment,
if any.

Probably an hour's work; no special test bars needed.

Cheers,

John B.
(johnbslocomatgmaildotcom)
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Default Preliminary "test bar" lathe measurements.

Iggy,
You are going to use more than 2 hours...find a friend and plan for all day. This is finicky stuff and you will be continually
remeasuring for consistency. I really don't like the idea of the spindle adapter. Getting the test bar mounted straight will be
problematic but essential.
Steve

"Ignoramus7752" wrote in message ...
Kevin, I have been procrastinating about leveling this lathe, but yes,
I should get my act together and start leveling. I do have a machinist
level. It is just a matter of finding 2 hours to do it right.

i


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Default Preliminary "test bar" lathe measurements.

On Fri, 29 Jan 2010 23:22:52 +0100, I wrote:

What the method does not eliminate, are two things: Lack of roundness
of the test bar (on the measuring points) and droop of the test bar
when measuring high/low alignment. The former is easy to eliminate:
Just take a light cut until the cut is contiguous.


I just thought of an important detail: The two measurement points must
be the same diameter. If you decide to turn them round, you have to be
accurate. It's easier to use something that's already accurately
round, such as a shock absorber rod.
--
RoRo
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Default Preliminary "test bar" lathe measurements.

On Thu, 28 Jan 2010 22:06:52 -0600, Ignoramus2532
wrote:

I bought a "test bar", which is a 10" or so long with MT3 end.

I inserted centers in the headstock and tailstock and mounted the bar
between those. Then I aligned tailstock with headstock, such that the
position of the indicator was the same at both ends.

This gave me about 6 inches of travel along the straight portion of the
test bar.

The good news is that the travel of the indicator, as I moved the
carriage from one end to another over 6 inches of distance, did not
seem to exceed 0.0003" or so.

Of course, aligning tailstock using position of carriage as a
reference, and them measuring deflection of the indicator on carriage
using the bar as reference, is a little bit "self referential".

In other words, the indicator does not really tell me if the carriage
moves parallel to the imaginary axis of the spindle rotation, because
that axis was not used in any way. But what the indicator does tell
me, is that along those 6 inches, the carriage moves on a straight
line.

That is already something and is much better than what happened with
my old lathe, where the carriage moved along a jumpy line (as
evidenced by abrupt changes in thickness of a test cut).

I will try to do more measurements.

i


Seems me that you have checked the rough measurements just fine, now
start using the damned thing!

Gunner, who bought a Van Norman #36 this week, with 500lbs of tooling,
indexer etc etc etc for $1500 (plus a $300 moving charge..sigh) and it
had been rebuilt 12 yrs ago, and seldom used since then.




Whenever a Liberal utters the term "Common Sense approach"....grab your
wallet, your ass, and your guns because the sombitch is about to do
something damned nasty to all three of them.


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Default Preliminary "test bar" lathe measurements.

Gunner Asch wrote:

Gunner, who bought a Van Norman #36 this week, with 500lbs of tooling,
indexer etc etc etc for $1500 (plus a $300 moving charge..sigh) and it
had been rebuilt 12 yrs ago, and seldom used since then.


Missed Michigan did you? IIRC, Van Norman was produced in Grand Rapids.

Wes
--
"Additionally as a security officer, I carry a gun to protect
government officials but my life isn't worth protecting at home
in their eyes." Dick Anthony Heller
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Default Preliminary "test bar" lathe measurements.

On 2010-02-07, Gunner Asch wrote:

Seems me that you have checked the rough measurements just fine, now
start using the damned thing!


Yep... Time to start using... Yesterday I faced a backing plate for a
chuck... Life is good.

Gunner, who bought a Van Norman #36 this week, with 500lbs of tooling,
indexer etc etc etc for $1500 (plus a $300 moving charge..sigh) and it
had been rebuilt 12 yrs ago, and seldom used since then.


Is that a horizontal mill? 6000 lbs or so?

i
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Default Preliminary "test bar" lathe measurements.

On Sat, 06 Feb 2010 19:44:25 -0500, Wes wrote:

Gunner Asch wrote:

Gunner, who bought a Van Norman #36 this week, with 500lbs of tooling,
indexer etc etc etc for $1500 (plus a $300 moving charge..sigh) and it
had been rebuilt 12 yrs ago, and seldom used since then.


Missed Michigan did you? IIRC, Van Norman was produced in Grand Rapids.

Wes


Indeed. Ive been jonesing really bad for a Van Norman or K&T for
years..and this came up while I was setting up a new shop for a guy.

And I get to use it whenever I want!! Yay!!!


Gunner

Whenever a Liberal utters the term "Common Sense approach"....grab your
wallet, your ass, and your guns because the sombitch is about to do
something damned nasty to all three of them.
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Default Preliminary "test bar" lathe measurements.

On Sat, 06 Feb 2010 20:53:42 -0600, Ignoramus20464
wrote:

On 2010-02-07, Gunner Asch wrote:

Seems me that you have checked the rough measurements just fine, now
start using the damned thing!


Yep... Time to start using... Yesterday I faced a backing plate for a
chuck... Life is good.

Gunner, who bought a Van Norman #36 this week, with 500lbs of tooling,
indexer etc etc etc for $1500 (plus a $300 moving charge..sigh) and it
had been rebuilt 12 yrs ago, and seldom used since then.


Is that a horizontal mill? 6000 lbs or so?

i

Horizontal/Verticle..and yeah..its got to be close to 6000 lbs. Data
sheet specs it as 4500, but I suspect with all the doodads and
whatnot..including that 3 axis DRO...its heavier.

Gunner

Whenever a Liberal utters the term "Common Sense approach"....grab your
wallet, your ass, and your guns because the sombitch is about to do
something damned nasty to all three of them.
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Default Preliminary "test bar" lathe measurements.

On Feb 6, 7:09*pm, Gunner Asch wrote:
On Thu, 28 Jan 2010 22:06:52 -0600, Ignoramus2532





wrote:
I bought a "test bar", which is a 10" or so long with MT3 end.


I inserted centers in the headstock and tailstock and mounted the bar
between those. Then I aligned tailstock with headstock, such that the
position of the indicator was the same at both ends.


This gave me about 6 inches of travel along the straight portion of the
test bar.


The good news is that the travel of the indicator, as I moved the
carriage from one end to another over 6 inches of distance, did not
seem to exceed 0.0003" or so.


Of course, aligning tailstock using position of carriage as a
reference, and them measuring deflection of the indicator on carriage
using the bar as reference, is a little bit "self referential".


In other words, the indicator does not really tell me if the carriage
moves parallel to the imaginary axis of the spindle rotation, because
that axis was not used in any way. But what the indicator does tell
me, is that along those 6 inches, the carriage moves on a straight
line.


That is already something and is much better than what happened with
my old lathe, where the carriage moved along a jumpy line (as
evidenced by abrupt changes in thickness of a test cut).


I will try to do more measurements.


i


Seems me that you have checked the rough measurements just fine, now
start using the damned thing!

Gunner, who bought a Van Norman #36 this week, with 500lbs of tooling,
indexer etc etc etc for $1500 (plus a $300 moving charge..sigh) and it
had been rebuilt 12 yrs ago, and seldom used since then.

*Whenever a Liberal utters the term "Common Sense approach"....grab your
*wallet, your ass, and your guns because the sombitch is about to do
*something damned nasty to all three of them.


Bankrupt thief spend $1800 for even more crap that the state will
seize.
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