I have a runnout problem in the spindle on my CNC mill. means small
tooling, like endmills under 1/8" diameter break constantly. Driving
me nuts again this week.

Last year, I took the spindle apart and installed all new bearings -
no help.

I had read that the entire spindle cartridge could be sent in and have
the 40 taper reground to be exactly true. Not sure where a place like
this might be.

Any suggestions on my next step here?

Karl

Karl, how do you know, how did you prove to yourself that you have a
runout problem, and not, say, a following error problem.

i

On 2015-02-14, Karl Townsend wrote:
I have a runnout problem in the spindle on my CNC mill. means small
tooling, like endmills under 1/8" diameter break constantly. Driving
me nuts again this week.

Last year, I took the spindle apart and installed all new bearings -
no help.

I had read that the entire spindle cartridge could be sent in and have
the 40 taper reground to be exactly true. Not sure where a place like
this might be.

Any suggestions on my next step here?

Karl

"Karl Townsend" wrote in message
...
I have a runnout problem in the spindle on my CNC mill. means small
tooling, like endmills under 1/8" diameter break constantly. Driving
me nuts again this week.

Last year, I took the spindle apart and installed all new bearings -
no help.

I had read that the entire spindle cartridge could be sent in and
have
the 40 taper reground to be exactly true. Not sure where a place
like
this might be.

Any suggestions on my next step here?

Karl

I'd measure the runout at the endmill shank, also that of the 40 taper
ID, and their deflection under a side load from a spring scale, as I
did this morning for Robobass.

The quill shaft on my mill is worn and deflects when extended, meaning
I have to bore precision holes to final size by raising the knee.
-jsw

On Fri, 13 Feb 2015 18:34:20 -0600, Ignoramus4453
wrote:

Karl, how do you know, how did you prove to yourself that you have a
runout problem, and not, say, a following error problem.


I'm an engineer and a machinist, so I measured it VBG More runnout
at end of long tool holder, average about 1.4 thousanths. Best tool
was my hole centering guage, that way all you have to do is hold the
unit while rotating the quill by hand.

On Fri, 13 Feb 2015 18:09:02 -0600, Karl Townsend
wrote:

I have a runnout problem in the spindle on my CNC mill. means small
tooling, like endmills under 1/8" diameter break constantly. Driving
me nuts again this week.

Last year, I took the spindle apart and installed all new bearings -
no help.

I had read that the entire spindle cartridge could be sent in and have
the 40 taper reground to be exactly true. Not sure where a place like
this might be.

Any suggestions on my next step here?

Karl
Greetings Karl,
Some of the tool holders I have run out too much for small cutters.
Really, a 1/8 cutter should run true within a tenth, and a few of my
holders for small tools run out about 3 tenths. I made an eccentric
bushing for a small cutter but I don't like holding cutters in
bushings that slip in. So I am considering putting the tool holders in
the machine and boring them large enough to take a pressed in bushing.
Then boring to bushing in the holder in the spindle. Since all my
holders ALWAYS go in the same way the holder should always run true.
Eric

On Fri, 13 Feb 2015 18:09:02 -0600, Karl Townsend
wrote:

I have a runnout problem in the spindle on my CNC mill. means small
tooling, like endmills under 1/8" diameter break constantly. Driving
me nuts again this week.

Last year, I took the spindle apart and installed all new bearings -
no help.

I had read that the entire spindle cartridge could be sent in and have
the 40 taper reground to be exactly true. Not sure where a place like
this might be.

Any suggestions on my next step here?

Karl

http://www.spsspindle.com/sps-spindl...le-rebuilding/

However...keep in mind that if they grind the spindle taper..your tool
may not..not fill the hole..so they will also have to grind the nose
of the spindle and depending on how much metal they removed..they may
have to recut the holes for the alignment blocks. Generally when
regrinding..they will remove between .015-.05...but...shrug

Have you put a tenths indicator on the spindle taper and find out how
much out of alignment is inside the taper? That is #1 task.

Its entirely possible to have poorly ground or worn tool
holders..which will show up as a bad spindle alignment.

So put a tenths indcator on a holder and check at the inside of the
beginning of the taper..then stick it inside with the longest probe
you have and measure as far inside as you can.

This of course assumes there are ZERO high spots inside the spindle
nose. If there are high spots..they have to go away..hence a Dremel
tool etc etc will knock off high spots/burrs/damage. Better to have a
groove than a ridge.

Gunner

"At the core of liberalism is the spoiled child,
miserable, as all spoiled children are, unsatisfied,
demanding, ill-disciplined, despotic and useless.
Liberalism is a philosophy of sniveling brats."
PJ O'Rourke

On Fri, 13 Feb 2015 19:44:47 -0500, "Jim Wilkins"
wrote:

"Karl Townsend" wrote in message
.. .
I have a runnout problem in the spindle on my CNC mill. means small
tooling, like endmills under 1/8" diameter break constantly. Driving
me nuts again this week.

Last year, I took the spindle apart and installed all new bearings -
no help.

I had read that the entire spindle cartridge could be sent in and
have
the 40 taper reground to be exactly true. Not sure where a place
like
this might be.

Any suggestions on my next step here?

Karl

I'd measure the runout at the endmill shank, also that of the 40 taper
ID, and their deflection under a side load from a spring scale, as I
did this morning for Robobass.

The quill shaft on my mill is worn and deflects when extended, meaning
I have to bore precision holes to final size by raising the knee.
-jsw


Then thats NOT an ID issue..but an OD issue...which can be fi$ed by
having a shop strip the chrome, regrinding, rechroming and regriding
to size. Or replacing the quill with an unworn or less worn quill


"At the core of liberalism is the spoiled child,
miserable, as all spoiled children are, unsatisfied,
demanding, ill-disciplined, despotic and useless.
Liberalism is a philosophy of sniveling brats."
PJ O'Rourke

"Gunner Asch" wrote in message
...
On Fri, 13 Feb 2015 19:44:47 -0500, "Jim Wilkins"
wrote:

...
The quill shaft on my mill is worn and deflects when extended,
meaning
I have to bore precision holes to final size by raising the knee.
-jsw


Then thats NOT an ID issue..but an OD issue...which can be fi$ed by
having a shop strip the chrome, regrinding, rechroming and regriding
to size. Or replacing the quill with an unworn or less worn quill

Or do my precision boring jobs on the lathe, now that I know the mill
bores tapered.

It was only a few tenths, which mattered because I was rebushing a
hydraulic gear pump. If I rebore my air compressor I'll have to use
the knee anyway since the quill travel is only 3".

It's an early model Clausing 8525 with a poorly designed quill clamp
which they changed later.
-jsw

On 2/14/2015 9:00 PM, Gunner Asch wrote:
On Fri, 13 Feb 2015 18:09:02 -0600, Karl Townsend
wrote:

I have a runnout problem in the spindle on my CNC mill. means small
tooling, like endmills under 1/8" diameter break constantly. Driving
me nuts again this week.

Last year, I took the spindle apart and installed all new bearings -
no help.

I had read that the entire spindle cartridge could be sent in and have
the 40 taper reground to be exactly true. Not sure where a place like
this might be.

Any suggestions on my next step here?

Karl

http://www.spsspindle.com/sps-spindl...le-rebuilding/

However...keep in mind that if they grind the spindle taper..your tool
may not..not fill the hole..so they will also have to grind the nose
of the spindle and depending on how much metal they removed..they may
have to recut the holes for the alignment blocks. Generally when
regrinding..they will remove between .015-.05...but...shrug

Have you put a tenths indicator on the spindle taper and find out how
much out of alignment is inside the taper? That is #1 task.

Its entirely possible to have poorly ground or worn tool
holders..which will show up as a bad spindle alignment.

So put a tenths indcator on a holder and check at the inside of the
beginning of the taper..then stick it inside with the longest probe
you have and measure as far inside as you can.

This of course assumes there are ZERO high spots inside the spindle
nose. If there are high spots..they have to go away..hence a Dremel
tool etc etc will knock off high spots/burrs/damage. Better to have a
groove than a ridge.

Gunner

It might be as simple as oil. Or as I found in Dad's lathe when I got it,
the chuck was running a bit off - and there was a chunk of swarf from
inside of the chuck - in the chuck threads. It was pressed on like
everything. The chuck wasn't sitting square. I was able to clean the
thread and clean the chuck for other junk. The chuck screwed onto
the spindle as it should and mounded square on it. The chuck was
back to the normal quality. It had baffled dad, but I think his
eyesight was going badly by then and he missed the smear of steel.

Martin

On Sat, 14 Feb 2015 22:24:36 -0600, Martin Eastburn
wrote:

On 2/14/2015 9:00 PM, Gunner Asch wrote:
On Fri, 13 Feb 2015 18:09:02 -0600, Karl Townsend
wrote:

I have a runnout problem in the spindle on my CNC mill. means small
tooling, like endmills under 1/8" diameter break constantly. Driving
me nuts again this week.

Last year, I took the spindle apart and installed all new bearings -
no help.

I had read that the entire spindle cartridge could be sent in and have
the 40 taper reground to be exactly true. Not sure where a place like
this might be.

Any suggestions on my next step here?

Karl

http://www.spsspindle.com/sps-spindl...le-rebuilding/

However...keep in mind that if they grind the spindle taper..your tool
may not..not fill the hole..so they will also have to grind the nose
of the spindle and depending on how much metal they removed..they may
have to recut the holes for the alignment blocks. Generally when
regrinding..they will remove between .015-.05...but...shrug

Have you put a tenths indicator on the spindle taper and find out how
much out of alignment is inside the taper? That is #1 task.

Its entirely possible to have poorly ground or worn tool
holders..which will show up as a bad spindle alignment.

So put a tenths indcator on a holder and check at the inside of the
beginning of the taper..then stick it inside with the longest probe
you have and measure as far inside as you can.

This of course assumes there are ZERO high spots inside the spindle
nose. If there are high spots..they have to go away..hence a Dremel
tool etc etc will knock off high spots/burrs/damage. Better to have a
groove than a ridge.

Gunner

It might be as simple as oil. Or as I found in Dad's lathe when I got it,
the chuck was running a bit off - and there was a chunk of swarf from
inside of the chuck - in the chuck threads. It was pressed on like
everything. The chuck wasn't sitting square. I was able to clean the
thread and clean the chuck for other junk. The chuck screwed onto
the spindle as it should and mounded square on it. The chuck was
back to the normal quality. It had baffled dad, but I think his
eyesight was going badly by then and he missed the smear of steel.

Martin

Good catch! I have both 30 and 40 Nmtb tooling for the Gorton
MasterMill and the Larios horizontal and I religiously run a
scotchbrite inside both spindle tapers a couple times a year. I
generally dont change my tool holders very often, I use
interchangeable collets inside the tool holders..but they get cleaned
regularly as well. Both have .0001 runout..I can live with that I
think...
My Hardinge HLV-H had some swarf in the tailstock taper that had been
mashed in pretty badly..so I borrowed a #2 MT finishing reamer and
just touched it off and now I use a bright flashlight to look inside
now and then. Couldnt figure out why my centerdrills were .015 to the
side and it was driving me nuts.

Gunner

"At the core of liberalism is the spoiled child,
miserable, as all spoiled children are, unsatisfied,
demanding, ill-disciplined, despotic and useless.
Liberalism is a philosophy of sniveling brats."
PJ O'Rourke

This of course assumes there are ZERO high spots inside the spindle
nose. If there are high spots..they have to go away..hence a Dremel
tool etc etc will knock off high spots/burrs/damage. Better to have a
groove than a ridge.

I cannot find runnout inside the spindle. AND its more the longer the
tool holder. My theory, a couple of G0 schmucks of the spindle has
bent it. Seen this in your experience?

I'm ruling out toolholders. The same holder runs near 0 runnout in the
other machine. And it don't break small endmills. several different
holders with the same results here.


Another possible is high spots I heven't detected. Do I dare take a
taper 40 reamer to it lightly? Would I be better off using a tool
holder and lapping compound?

I'm afraid of the cost of the place you suggest, but maybe I should
just bite the bullet and be done with it

thanks for your advice

Karl

"Karl Townsend" wrote in message
news

This of course assumes there are ZERO high spots inside the spindle
nose. If there are high spots..they have to go away..hence a Dremel
tool etc etc will knock off high spots/burrs/damage. Better to have
a
groove than a ridge.

I cannot find runnout inside the spindle. AND its more the longer
the
tool holder. My theory, a couple of G0 schmucks of the spindle has
bent it. Seen this in your experience?

I'm ruling out toolholders. The same holder runs near 0 runnout in
the
other machine. And it don't break small endmills. several different
holders with the same results here.


Another possible is high spots I heven't detected. Do I dare take a
taper 40 reamer to it lightly? Would I be better off using a tool
holder and lapping compound?

I'm afraid of the cost of the place you suggest, but maybe I should
just bite the bullet and be done with it

thanks for your advice

Karl

At some time in its 60+ years my Clausing acquired a slight spindle
taper runout, which I fixed with Wholesale Tool's last, chipped, B&S
#7 reamer. Holding the reamer straight and centered against the offset
cutting load proved difficult. It wanted to ride up off the center
point on the table.
-jsw

On Sun, 15 Feb 2015 08:11:22 -0600, Karl Townsend
wrote:


This of course assumes there are ZERO high spots inside the spindle
nose. If there are high spots..they have to go away..hence a Dremel
tool etc etc will knock off high spots/burrs/damage. Better to have a
groove than a ridge.

I cannot find runnout inside the spindle. AND its more the longer the
tool holder. My theory, a couple of G0 schmucks of the spindle has
bent it. Seen this in your experience?
Unfortunately..I have see it.


I'm ruling out toolholders. The same holder runs near 0 runnout in the
other machine. And it don't break small endmills. several different
holders with the same results here.

Ah! Ayup..out of alinement


Another possible is high spots I heven't detected. Do I dare take a
taper 40 reamer to it lightly? Would I be better off using a tool
holder and lapping compound?

Shrug..both are harder than a hookers heart. Generally..not
always..but generally....the tool holder is softer than the spindle.
Im not sure what to suggest at this point.

I'm afraid of the cost of the place you suggest, but maybe I should
just bite the bullet and be done with it

Give em a call and ask about their price. Its an easy job for
them..they might give you a break as you are a hobby guy, not a pro
shop.

thanks for your advice

Karl

"At the core of liberalism is the spoiled child,
miserable, as all spoiled children are, unsatisfied,
demanding, ill-disciplined, despotic and useless.
Liberalism is a philosophy of sniveling brats."
PJ O'Rourke

On Sun, 15 Feb 2015 09:51:49 -0500, "Jim Wilkins"
wrote:

"Karl Townsend" wrote in message
news

This of course assumes there are ZERO high spots inside the spindle
nose. If there are high spots..they have to go away..hence a Dremel
tool etc etc will knock off high spots/burrs/damage. Better to have
a
groove than a ridge.

I cannot find runnout inside the spindle. AND its more the longer
the
tool holder. My theory, a couple of G0 schmucks of the spindle has
bent it. Seen this in your experience?

I'm ruling out toolholders. The same holder runs near 0 runnout in
the
other machine. And it don't break small endmills. several different
holders with the same results here.


Another possible is high spots I heven't detected. Do I dare take a
taper 40 reamer to it lightly? Would I be better off using a tool
holder and lapping compound?

I'm afraid of the cost of the place you suggest, but maybe I should
just bite the bullet and be done with it

thanks for your advice

Karl

At some time in its 60+ years my Clausing acquired a slight spindle
taper runout, which I fixed with Wholesale Tool's last, chipped, B&S
#7 reamer. Holding the reamer straight and centered against the offset
cutting load proved difficult. It wanted to ride up off the center
point on the table.
-jsw

Ayup..unless you can anchor that sucker tightly...it will always be an
issue reaming a spindle bore.

"At the core of liberalism is the spoiled child,
miserable, as all spoiled children are, unsatisfied,
demanding, ill-disciplined, despotic and useless.
Liberalism is a philosophy of sniveling brats."
PJ O'Rourke

Karl Townsend on Sun, 15 Feb 2015
08:11:22 -0600 typed in rec.crafts.metalworking the following:

This of course assumes there are ZERO high spots inside the spindle
nose. If there are high spots..they have to go away..hence a Dremel
tool etc etc will knock off high spots/burrs/damage. Better to have a
groove than a ridge.

I cannot find runnout inside the spindle. AND its more the longer the
tool holder. My theory, a couple of G0 schmucks of the spindle has
bent it. Seen this in your experience?

I'm ruling out toolholders. The same holder runs near 0 runnout in the
other machine. And it don't break small endmills. several different
holders with the same results here.


Another possible is high spots I heven't detected. Do I dare take a
taper 40 reamer to it lightly? Would I be better off using a tool
holder and lapping compound?

I'm afraid of the cost of the place you suggest, but maybe I should
just bite the bullet and be done with it

OTOH, how much are you spending in broken tools? Some times you
just have to ask "Am I able to make up what it costs on each one, in
volume?"
--
pyotr filipivich
"With Age comes Wisdom. Although more often, Age travels alone."

Karl Townsend wrote:


Another possible is high spots I heven't detected. Do I dare take a
taper 40 reamer to it lightly? Would I be better off using a tool
holder and lapping compound?
If you can spin a holder in the taper (maybe by removing the drive dogs
temporarily) you can get a good idea of what is going on.

Two ways to do it. One is to smear a VERY thin film of spotting dye
inside the spindle, and then work the holder in and give it a small
twist when gently seated. Turn it less than 1/8th turn, then pull
out and look for a streak of dye on the holder. Then, you have to
figure out where in the spindle the high spot is. The clear indication
will be one side of the holder has a wide print of dye, the other side
has just one small mark.

The other way is to coat the holder fairly lightly, and wring it into
the spindle. Then, you need a REALLY good light to see up in the
spindle. You may need a mirror to keep from twisting you neck
into a knot trying to see into the spindle. This should point out
any bumps in the spindle taper. Any big dings will produce a
"crater rim" around the ding. So, a bull's eye pattern is for sure
what you are looking for. You may be able to remove these with a
Swiss file or a curved piece of steel working it like a scraping
blade on the ding. Don't worry about leaving a tiny low spot
in the spindle taper, it will not affect the accuracy at all, but a
high spot will cause the tool holder to rock in the spindle, that's
even WORSE that a little eccentricity. Although, it sounds like
you have MORE than a "little" eccentricity going on there.

Jon