I'm restoring my 1963 Clausing 8520 mill ( pictures here if interested
http://gallery.intlwaters.com/thumbnails.php?album=323 )
and in the process am replacing the spindle bearings. I've read through
many posts on the Yahoo Group and have just gotten more confused.
Talked to a few bearing "engineers" (ya right) at SKF and they don't seem to
have solid answers either.

The spindle takes a pair of 7205 angular contact bearings that are held in
place by a locking washer and nut. I was able to find on the MRC site that
the torque on the nut should be 23-50 ft-lb. but can't seem to find answers
to the following:

Should the bearings be mounted "face to face" (where the contact lines of
the bearings converge inward), or "back to back"?

I can order bearings that are ground and sold as a matching set in either "b
to b" or "f to f" that when mounted together and the retaining nut tightened
give a "light preload".

I can also order bearings that are not matched but are for "universal
pairing" that are about half the cost and are made to mount either way.
Some posts on the Yahoo Group mention that to apply a preload to these
bearings a shim is needed between them either on the inner or outer race,
others say none is needed. If the bearings are made to mount either way how
can they be preloaded without the use of a shim? If needed how thick should
it be?

The machine came fitted with standard bearings and no shims so I can't go by
what was there.

Any experts here? Thanks in advance!

On Thu, 1 Dec 2005 09:20:18 -0500, "Terry Keeley" tkee(no spam)@(or
mail)rogers.com wrote:

Greetings Terry,
I assume you have contacted Clausing asking them how to mount the
bearings. If not, try, maybe they can help. They helped me a few years
ago with questions about an Atlas lathe. I have spoken with both SKF
and NTN engineers. Both were helpful. But I also had to go through
some younger engineers to finally speak to older ones with more
experience. You need to be able to tell the engineer how the bearings
are mounted. The mount limits the options. The lines converging or
diverging regulate the stiffness of the assembly. Try SKF again and
insist, politely, to speak to someone who really knows.
ERS
I'm restoring my 1963 Clausing 8520 mill ( pictures here if interested
http://gallery.intlwaters.com/thumbnails.php?album=323 )
and in the process am replacing the spindle bearings. I've read through
many posts on the Yahoo Group and have just gotten more confused.
Talked to a few bearing "engineers" (ya right) at SKF and they don't seem to
have solid answers either.

The spindle takes a pair of 7205 angular contact bearings that are held in
place by a locking washer and nut. I was able to find on the MRC site that
the torque on the nut should be 23-50 ft-lb. but can't seem to find answers
to the following:

Should the bearings be mounted "face to face" (where the contact lines of
the bearings converge inward), or "back to back"?

I can order bearings that are ground and sold as a matching set in either "b
to b" or "f to f" that when mounted together and the retaining nut tightened
give a "light preload".

I can also order bearings that are not matched but are for "universal
pairing" that are about half the cost and are made to mount either way.
Some posts on the Yahoo Group mention that to apply a preload to these
bearings a shim is needed between them either on the inner or outer race,
others say none is needed. If the bearings are made to mount either way how
can they be preloaded without the use of a shim? If needed how thick should
it be?

The machine came fitted with standard bearings and no shims so I can't go by
what was there.

Any experts here? Thanks in advance!

Thanks Eric, you're right I'm sure, the person that was recommended at SKF
was on the road for the week so I asked if anyone else could help...

Not sure about Clausing, posts on the Yahoo Group weren't too encouraging.


"Eric R Snow" wrote in message
...
On Thu, 1 Dec 2005 09:20:18 -0500, "Terry Keeley" tkee(no spam)@(or
mail)rogers.com wrote:

Greetings Terry,
I assume you have contacted Clausing asking them how to mount the
bearings. If not, try, maybe they can help. They helped me a few years
ago with questions about an Atlas lathe. I have spoken with both SKF
and NTN engineers. Both were helpful. But I also had to go through
some younger engineers to finally speak to older ones with more
experience. You need to be able to tell the engineer how the bearings
are mounted. The mount limits the options. The lines converging or
diverging regulate the stiffness of the assembly. Try SKF again and
insist, politely, to speak to someone who really knows.
ERS

In article , no spam says...

The spindle takes a pair of 7205 angular contact bearings that are held in
place by a locking washer and nut. I was able to find on the MRC site that
the torque on the nut should be 23-50 ft-lb. but can't seem to find answers
to the following:

Should the bearings be mounted "face to face" (where the contact lines of
the bearings converge inward), or "back to back"?

Just out of curiosity, were the originals bb or ff? My first take on
it would be to replicate the original setup.

I can order bearings that are ground and sold as a matching set in either "b
to b" or "f to f" that when mounted together and the retaining nut tightened
give a "light preload".

I can also order bearings that are not matched but are for "universal
pairing" that are about half the cost and are made to mount either way.
Some posts on the Yahoo Group mention that to apply a preload to these
bearings a shim is needed between them either on the inner or outer race,
others say none is needed. If the bearings are made to mount either way how
can they be preloaded without the use of a shim? If needed how thick should
it be?

If you do this without any shims the bearings will have way too much
clearance I suspect. What bridgeport used to do was to grind the face
of the bearing race to set this, rather than use shims, on the M heads.

My first take would be to order the same type (bb or ff) as the original
bearings, and purchase them as a true angular contact pair.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

In article ,
"Terry Keeley" tkee(no spam)@(or mail)rogers.com says...
I'm restoring my 1963 Clausing 8520 mill ( pictures here if interested
http://gallery.intlwaters.com/thumbnails.php?album=323 )
and in the process am replacing the spindle bearings. I've read through
many posts on the Yahoo Group and have just gotten more confused.
Talked to a few bearing "engineers" (ya right) at SKF and they don't seem to
have solid answers either.

The spindle takes a pair of 7205 angular contact bearings that are held in
place by a locking washer and nut. I was able to find on the MRC site that
the torque on the nut should be 23-50 ft-lb. but can't seem to find answers
to the following:

Should the bearings be mounted "face to face" (where the contact lines of
the bearings converge inward), or "back to back"?

Almost certainly back to back.


I can order bearings that are ground and sold as a matching set in either "b
to b" or "f to f" that when mounted together and the retaining nut tightened
give a "light preload".

I can also order bearings that are not matched but are for "universal
pairing" that are about half the cost and are made to mount either way.
Some posts on the Yahoo Group mention that to apply a preload to these
bearings a shim is needed between them either on the inner or outer race,
others say none is needed. If the bearings are made to mount either way how
can they be preloaded without the use of a shim? If needed how thick should
it be?

You'll have to ask the bearing mfr for a definitive answer
on the spacer thickness, but I wouldn't recommend this
approach. A few tenths will make a big difference in the
preload, possibly resulting in overheating or loss of
rigidity, depending on whether the shim is too thick or too
thin. Best to buy the proper matching set of bearings. A
matched pair of precision 7207s should cost you around
$275.

Ned Simmons

..
Just out of curiosity, were the originals bb or ff? My first take on
it would be to replicate the original setup.


Thanks for the help but someone installed regular standard ball bearings so
I don't have any history to go by.


I can order bearings that are ground and sold as a matching set in either
"b
to b" or "f to f" that when mounted together and the retaining nut
tightened
give a "light preload".

I can also order bearings that are not matched but are for "universal
pairing" that are about half the cost and are made to mount either way.
Some posts on the Yahoo Group mention that to apply a preload to these
bearings a shim is needed between them either on the inner or outer race,
others say none is needed. If the bearings are made to mount either way
how
can they be preloaded without the use of a shim? If needed how thick
should
it be?

If you do this without any shims the bearings will have way too much
clearance I suspect. What bridgeport used to do was to grind the face
of the bearing race to set this, rather than use shims, on the M heads.

My first take would be to order the same type (bb or ff) as the original
bearings, and purchase them as a true angular contact pair.

Jim

Think this might be the way to go also but most don't seem to go this
route...




--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

In article , Ned Simmons
says...

You'll have to ask the bearing mfr for a definitive answer
on the spacer thickness, but I wouldn't recommend this
approach. A few tenths will make a big difference in the
preload, possibly resulting in overheating or loss of
rigidity, depending on whether the shim is too thick or too
thin.

Agree. When I was doing this with non-setup bearings
I was taking a tenth off the spacers at the end while
doing trials.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

Terry,

When I replaced mine I bought the bearings from Clausing as a match set.
There was no shim needed/supplied). When I installed them I realized
there was two ways to do it. I mounted them so that when they were
mounted on the spindle they were "tight". I don't remember if I ever
figured out if this was the official direction or not, but I never had
any problems. This way make since to me because the spindle nut has a
locking feature, and the retaining nut does not. If the nut backs off,
then you have lost the preload (bad thing).

I did have a heating problem, but that was because I filled the bears
completely with grease, and at the 2 highest speeds things over heated.
Found out later that you should fill the bearings 1/3 rd with grease.
Once I removed most of the grease it ran fine. You do this by filling
1/3 rd of the bearing 100% with grease, and then spinning the bearing
around until it's even.

Hope this helps,

Vince



Terry Keeley wrote:
I'm restoring my 1963 Clausing 8520 mill ( pictures here if interested
http://gallery.intlwaters.com/thumbnails.php?album=323 )
and in the process am replacing the spindle bearings. I've read through
many posts on the Yahoo Group and have just gotten more confused.
Talked to a few bearing "engineers" (ya right) at SKF and they don't seem to
have solid answers either.

The spindle takes a pair of 7205 angular contact bearings that are held in
place by a locking washer and nut. I was able to find on the MRC site that
the torque on the nut should be 23-50 ft-lb. but can't seem to find answers
to the following:

Should the bearings be mounted "face to face" (where the contact lines of
the bearings converge inward), or "back to back"?

I can order bearings that are ground and sold as a matching set in either "b
to b" or "f to f" that when mounted together and the retaining nut tightened
give a "light preload".

I can also order bearings that are not matched but are for "universal
pairing" that are about half the cost and are made to mount either way.
Some posts on the Yahoo Group mention that to apply a preload to these
bearings a shim is needed between them either on the inner or outer race,
others say none is needed. If the bearings are made to mount either way how
can they be preloaded without the use of a shim? If needed how thick should
it be?

The machine came fitted with standard bearings and no shims so I can't go by
what was there.

Any experts here? Thanks in advance!

Thanks for the help!

So when you put them on and tightened up the nut it applied the pre-load?

I'd hear tat about the grease, thanks.

"Vince Iorio" wrote in message
...
Terry,

When I replaced mine I bought the bearings from Clausing as a match set.
There was no shim needed/supplied). When I installed them I realized
there was two ways to do it. I mounted them so that when they were
mounted on the spindle they were "tight". I don't remember if I ever
figured out if this was the official direction or not, but I never had
any problems. This way make since to me because the spindle nut has a
locking feature, and the retaining nut does not. If the nut backs off,
then you have lost the preload (bad thing).

I did have a heating problem, but that was because I filled the bears
completely with grease, and at the 2 highest speeds things over heated.
Found out later that you should fill the bearings 1/3 rd with grease.
Once I removed most of the grease it ran fine. You do this by filling
1/3 rd of the bearing 100% with grease, and then spinning the bearing
around until it's even.

Hope this helps,

Vince



Terry Keeley wrote:
I'm restoring my 1963 Clausing 8520 mill ( pictures here if interested
http://gallery.intlwaters.com/thumbnails.php?album=323 )
and in the process am replacing the spindle bearings. I've read through
many posts on the Yahoo Group and have just gotten more confused.
Talked to a few bearing "engineers" (ya right) at SKF and they don't
seem to
have solid answers either.

The spindle takes a pair of 7205 angular contact bearings that are held
in
place by a locking washer and nut. I was able to find on the MRC site
that
the torque on the nut should be 23-50 ft-lb. but can't seem to find
answers
to the following:

Should the bearings be mounted "face to face" (where the contact lines
of
the bearings converge inward), or "back to back"?

I can order bearings that are ground and sold as a matching set in
either "b
to b" or "f to f" that when mounted together and the retaining nut
tightened
give a "light preload".

I can also order bearings that are not matched but are for "universal
pairing" that are about half the cost and are made to mount either way.
Some posts on the Yahoo Group mention that to apply a preload to these
bearings a shim is needed between them either on the inner or outer
race,
others say none is needed. If the bearings are made to mount either way
how
can they be preloaded without the use of a shim? If needed how thick
should
it be?

The machine came fitted with standard bearings and no shims so I can't
go by
what was there.

Any experts here? Thanks in advance!

Terry,

Ask to speak with Jo(lene) Olds at Clausing, if she is still there. She's
been pretty helpful to me in the past.

Mike


"Terry Keeley" tkee(no spam)@(or mail)rogers.com wrote in message
.. .
Thanks Eric, you're right I'm sure, the person that was recommended at SKF
was on the road for the week so I asked if anyone else could help...

Not sure about Clausing, posts on the Yahoo Group weren't too encouraging.


"Eric R Snow" wrote in message
...
On Thu, 1 Dec 2005 09:20:18 -0500, "Terry Keeley" tkee(no spam)@(or
mail)rogers.com wrote:

Greetings Terry,
I assume you have contacted Clausing asking them how to mount the
bearings. If not, try, maybe they can help. They helped me a few years
ago with questions about an Atlas lathe. I have spoken with both SKF
and NTN engineers. Both were helpful. But I also had to go through
some younger engineers to finally speak to older ones with more
experience. You need to be able to tell the engineer how the bearings
are mounted. The mount limits the options. The lines converging or
diverging regulate the stiffness of the assembly. Try SKF again and
insist, politely, to speak to someone who really knows.
ERS

"Terry Keeley" tkee(no spam)@(or mail)rogers.com wrote in message
.. .
I'm restoring my 1963 Clausing 8520 mill ( pictures here if interested
http://gallery.intlwaters.com/thumbnails.php?album=323 )
and in the process am replacing the spindle bearings. I've read through
many posts on the Yahoo Group and have just gotten more confused.
Talked to a few bearing "engineers" (ya right) at SKF and they don't seem
to
have solid answers either.

The spindle takes a pair of 7205 angular contact bearings that are held in
place by a locking washer and nut. I was able to find on the MRC site
that
the torque on the nut should be 23-50 ft-lb. but can't seem to find
answers
to the following:

Should the bearings be mounted "face to face" (where the contact lines of
the bearings converge inward), or "back to back"?

I can order bearings that are ground and sold as a matching set in either
"b
to b" or "f to f" that when mounted together and the retaining nut
tightened
give a "light preload".

I can also order bearings that are not matched but are for "universal
pairing" that are about half the cost and are made to mount either way.
Some posts on the Yahoo Group mention that to apply a preload to these
bearings a shim is needed between them either on the inner or outer race,
others say none is needed. If the bearings are made to mount either way
how
can they be preloaded without the use of a shim? If needed how thick
should
it be?

The machine came fitted with standard bearings and no shims so I can't go
by
what was there.

Any experts here? Thanks in advance!

FWIW, the replacement bearings I ordered from Clausing a few years ago are
Fafnir 7205WN SU. I haven't installed them yet, but it looks like it might
be necessary pretty soon. There are one or two files in the Yahoo Clausing
group that describe bearing replacement, I think. I've archived off two
from there or elsewhere, complete with pictures. Email me if you can't find
them at the Yahoo group.

Following is the only info that Clausing could supply me on the spindle
(note that no "sample" was attached):

ASSEMBLING SPINDLE AND QUILL ASSEMBLY FOR CLAUSING MILL

1. Press 044-005 bearings one at a time on 701-004 spindle. Apply pressure
on inner race only and use DB mounting as shown in instructions supplied
with bearing - sample attached.


2.Slide 932-011 lock tab washer on spindle with inner tab in keyway.

3. Turn 537-020 nut on spindle and tighten securely against inner race of
bearing. Bend a tab on the 932-011 lock washer into a matching slot of the
537-020 nut.

4. Place the spindle in the 631-001 quill - 044-005 bearings in the threaded
end.


5. Press the 044-006 bearing on the spindle as far as it will go - apply
pressure on inner race only and support spindle on nose only.


6. Assembly 708-001 oil seal in 641-008 retainer as shown in attached
sketch.


7. Turn 641-008 retainer in quill -firm but not too tight.


8. Place M6-214 lead ball in threaded hole in quill and lock retainer with
#10-32 x 3/16" socket set screw.




INSTRUCTIONS FOR REMOVING NO.8520-25 V-MILL SPINDLE ASSEMBLY

1. Remove (2) 1/4" socket set screws from No.537-014 knurled nut located on
top of spindle, then remove knurl nut from spindle.


2. Remove (4) 1/4" machine screws (2 on each side of guard) which screws
guard No.342-020 to head casting. remove guard by pulling forward.

3. Remove (4) screws which screws plate No.386-009 containing pinion and
compound gears. Tap plate lightly on edge while prying outward with screw
driver to remove from dowell pins.


4. Remove socket set screw in No.233-001 dial and lift or pry up on stop
screw No.696-007 until top of screw is against spindle pulley, push quill to
bottom position.


5. Remove 1/4-20 socket cap screw holding stationary stop to face of quill.
With stop removed, remove quill assembly from head, reverse procedure to
install quill. Caution --be sure when installing spindle pulley guard that
brake lever is engaged in brake ring slot.

Thanks Mike, she's off having a knee replaced. Lee is the gal replacing
her, she's semi-retired and good also but I didn't think they'd be good at
this sort of thing...


"Mike Henry" wrote in message
...
Terry,

Ask to speak with Jo(lene) Olds at Clausing, if she is still there. She's
been pretty helpful to me in the past.

Mike


"Terry Keeley" tkee(no spam)@(or mail)rogers.com wrote in message
.. .
Thanks Eric, you're right I'm sure, the person that was recommended at
SKF
was on the road for the week so I asked if anyone else could help...

Not sure about Clausing, posts on the Yahoo Group weren't too
encouraging.


"Eric R Snow" wrote in message
...
On Thu, 1 Dec 2005 09:20:18 -0500, "Terry Keeley" tkee(no spam)@(or
mail)rogers.com wrote:

Greetings Terry,
I assume you have contacted Clausing asking them how to mount the
bearings. If not, try, maybe they can help. They helped me a few years
ago with questions about an Atlas lathe. I have spoken with both SKF
and NTN engineers. Both were helpful. But I also had to go through
some younger engineers to finally speak to older ones with more
experience. You need to be able to tell the engineer how the bearings
are mounted. The mount limits the options. The lines converging or
diverging regulate the stiffness of the assembly. Try SKF again and
insist, politely, to speak to someone who really knows.
ERS

Well those instructions kinda confirmed what I've been hearing from others
privately and also what an engineer at Barden said, it's back to back and
there are no shims involved. Interesting they don't specify a torque rating
for the locknut, I found that it's supposed to be 23-50 ft-lb. Thanks for
the help!




"Mike Henry" wrote in message
...

"Terry Keeley" tkee(no spam)@(or mail)rogers.com wrote in message
.. .
I'm restoring my 1963 Clausing 8520 mill ( pictures here if interested
http://gallery.intlwaters.com/thumbnails.php?album=323 )
and in the process am replacing the spindle bearings. I've read through
many posts on the Yahoo Group and have just gotten more confused.
Talked to a few bearing "engineers" (ya right) at SKF and they don't
seem
to
have solid answers either.

The spindle takes a pair of 7205 angular contact bearings that are held
in
place by a locking washer and nut. I was able to find on the MRC site
that
the torque on the nut should be 23-50 ft-lb. but can't seem to find
answers
to the following:

Should the bearings be mounted "face to face" (where the contact lines
of
the bearings converge inward), or "back to back"?

I can order bearings that are ground and sold as a matching set in
either
"b
to b" or "f to f" that when mounted together and the retaining nut
tightened
give a "light preload".

I can also order bearings that are not matched but are for "universal
pairing" that are about half the cost and are made to mount either way.
Some posts on the Yahoo Group mention that to apply a preload to these
bearings a shim is needed between them either on the inner or outer
race,
others say none is needed. If the bearings are made to mount either way
how
can they be preloaded without the use of a shim? If needed how thick
should
it be?

The machine came fitted with standard bearings and no shims so I can't
go
by
what was there.

Any experts here? Thanks in advance!

FWIW, the replacement bearings I ordered from Clausing a few years ago are
Fafnir 7205WN SU. I haven't installed them yet, but it looks like it
might
be necessary pretty soon. There are one or two files in the Yahoo
Clausing
group that describe bearing replacement, I think. I've archived off two
from there or elsewhere, complete with pictures. Email me if you can't
find
them at the Yahoo group.

Following is the only info that Clausing could supply me on the spindle
(note that no "sample" was attached):

ASSEMBLING SPINDLE AND QUILL ASSEMBLY FOR CLAUSING MILL

1. Press 044-005 bearings one at a time on 701-004 spindle. Apply pressure
on inner race only and use DB mounting as shown in instructions supplied
with bearing - sample attached.


2.Slide 932-011 lock tab washer on spindle with inner tab in keyway.

3. Turn 537-020 nut on spindle and tighten securely against inner race of
bearing. Bend a tab on the 932-011 lock washer into a matching slot of the
537-020 nut.

4. Place the spindle in the 631-001 quill - 044-005 bearings in the
threaded
end.


5. Press the 044-006 bearing on the spindle as far as it will go - apply
pressure on inner race only and support spindle on nose only.


6. Assembly 708-001 oil seal in 641-008 retainer as shown in attached
sketch.


7. Turn 641-008 retainer in quill -firm but not too tight.


8. Place M6-214 lead ball in threaded hole in quill and lock retainer with
#10-32 x 3/16" socket set screw.




INSTRUCTIONS FOR REMOVING NO.8520-25 V-MILL SPINDLE ASSEMBLY

1. Remove (2) 1/4" socket set screws from No.537-014 knurled nut located
on
top of spindle, then remove knurl nut from spindle.


2. Remove (4) 1/4" machine screws (2 on each side of guard) which screws
guard No.342-020 to head casting. remove guard by pulling forward.

3. Remove (4) screws which screws plate No.386-009 containing pinion and
compound gears. Tap plate lightly on edge while prying outward with screw
driver to remove from dowell pins.


4. Remove socket set screw in No.233-001 dial and lift or pry up on stop
screw No.696-007 until top of screw is against spindle pulley, push quill
to
bottom position.


5. Remove 1/4-20 socket cap screw holding stationary stop to face of
quill.
With stop removed, remove quill assembly from head, reverse procedure to
install quill. Caution --be sure when installing spindle pulley guard that
brake lever is engaged in brake ring slot.

In article , no spam says...

Thanks for the help!

So when you put them on and tightened up the nut it applied the pre-load?

The true preload on the front pair is built in at the factory. The
nut that tightens up the stack simply brings the inner races hard up
against each other. The outer races have to be constrained to
hard up against each other as well, this is typically done by
placing them in a pocket with some kind of clamp ring that bears
on the outer face of the outer bearing's outer race.

The bearing manufacture has them ground such that, as long as all
races are tight up against each other, the preload (or, tiny
amount of clearance) will be exactly correct. This is why true
angular contact pairs are so much more expensive.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

FWIW, the replacement bearings I ordered from Clausing a few years ago are
Fafnir 7205WN SU.


Just curious, are those angular contact bearings? I can't find those
numbers in the catalogue. The Fafnir numbers I'm getting are more like
2MM205WICRDUL, that's for a 25deg. Class 7 bearing.

In article , no spam says...

Well those instructions kinda confirmed what I've been hearing from others
privately and also what an engineer at Barden said, it's back to back and
there are no shims involved. Interesting they don't specify a torque rating
for the locknut, I found that it's supposed to be 23-50 ft-lb. Thanks for
the help!

Once again, the torque on the locknut does NOT set the preload.

It only assures that the preload that is built into the bearings
is achieved, and stays in place. Those things don't have to
be honkin' tight.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

"Terry Keeley" tkee(no spam)@(or mail)rogers.com wrote in message
...
FWIW, the replacement bearings I ordered from Clausing a few years ago
are
Fafnir 7205WN SU.


Just curious, are those angular contact bearings? I can't find those
numbers in the catalogue. The Fafnir numbers I'm getting are more like
2MM205WICRDUL, that's for a 25deg. Class 7 bearing.

You've got me - I'm no bearing expert.

Based on the info in this link:

http://www.timken.com/industries/tor...nir/radial.pdf

It looks like they are a light duty (72), 25 mm (05), angular contact (WN)
bearing, external self-aligning (S) - but no mention of what the "U" might
stand for.

From the old Chaski group:

"By what I can find in my Fafnir bearing book a 7205WN SU bearing is a :
Single row angular contact bearing
7200 series .. Light
7205 is the bearing size (25x52x15mm)
WN is 37* contact angle and heavy-duty retainer of bronze
SU is flush ground bearings for back-to-back, face-to-face, or tandem
mounting

There is no description of this bearing being any type of precision (5, 7 or
9), the difference between this bearing and a standard 7205 bearing is the
contact angle for combined thrust and radial loads.

I would see no reason that these bearings should not be replaced with the
orginal specifications (bearing class), but the angular contact and being
flush ground I would think would be very important. I would be cautious
about replacing with a standard 7205 ($5 bearing). "

By someone else in response to a question about using standard 7205 bearings
for the Clausing spindle.

Mike

On Thu, 1 Dec 2005 14:21:32 -0500, "Terry Keeley" tkee(no spam)@(or
mail)rogers.com wrote:

.
Just out of curiosity, were the originals bb or ff? My first take on
it would be to replicate the original setup.


Thanks for the help but someone installed regular standard ball bearings so
I don't have any history to go by.



Ive not removed bearings from your particular mill..but based on most
angular contact bearings...they should be mounted like this " "

With a hand snug preload.

I recently got into a beef with a well known CNC lathe manufacture
over angular contact bearings.. A brand new machine became noisy on
the Z axis after about 6 hours use. I tracked the noise down to a
thrust bearing between the ballscrew and the servo motor. Taking it
apart...I found the bearings to be mounted . They were
toasted..brinelled.

The bearings and their housing came pre assembled from a major high
quality bearing manufacture and not only did the machine become
nosiy..but z repeatability was all over the map...up to .0035+
variations.

The manufacture claimed it was the first time this was found..and
frankly they didnt believe me...so they sent out a their own tech to
check..and he replaced the bearing cartridge. Gee..suddenly it was
quiet and most of the repeatability issues went away.

2 days later..I had to replace a ballscrew and thrustbearing on a much
older machine made by the same manufacture. I pulled the bearing
housing apart on a lark..and found the bearings to be

I mentioned it to the customer..and he said he had always had an issue
doing a back turn.....

I suspect they really dont want to know about the second bearing I
found ..as it may open a can of worms they dont want opened. Shrug.

I figured that some gomer in Japan had too much saki and kereoki the
night before and assembled em wrong. The second bearing means there
are likely to be more bad ones out there....

All parties shall remain nameless.

Gunner



I can order bearings that are ground and sold as a matching set in either
"b
to b" or "f to f" that when mounted together and the retaining nut
tightened
give a "light preload".

I can also order bearings that are not matched but are for "universal
pairing" that are about half the cost and are made to mount either way.
Some posts on the Yahoo Group mention that to apply a preload to these
bearings a shim is needed between them either on the inner or outer race,
others say none is needed. If the bearings are made to mount either way
how
can they be preloaded without the use of a shim? If needed how thick
should
it be?

If you do this without any shims the bearings will have way too much
clearance I suspect. What bridgeport used to do was to grind the face
of the bearing race to set this, rather than use shims, on the M heads.

My first take would be to order the same type (bb or ff) as the original
bearings, and purchase them as a true angular contact pair.

Jim

Think this might be the way to go also but most don't seem to go this
route...




--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================


"Pax Americana is a philosophy. Hardly an empire.
Making sure other people play nice and dont kill each other (and us)
off in job lots is hardly empire building, particularly when you give
them self determination under "play nice" rules.

Think of it as having your older brother knock the **** out of you
for torturing the cat." Gunner

On Thu, 1 Dec 2005 13:52:36 -0500, Ned Simmons
wrote:

In article ,
"Terry Keeley" tkee(no spam)@(or mail)rogers.com says...
I'm restoring my 1963 Clausing 8520 mill ( pictures here if interested
http://gallery.intlwaters.com/thumbnails.php?album=323 )
and in the process am replacing the spindle bearings. I've read through
many posts on the Yahoo Group and have just gotten more confused.
Talked to a few bearing "engineers" (ya right) at SKF and they don't seem to
have solid answers either.

The spindle takes a pair of 7205 angular contact bearings that are held in
place by a locking washer and nut. I was able to find on the MRC site that
the torque on the nut should be 23-50 ft-lb. but can't seem to find answers
to the following:

Should the bearings be mounted "face to face" (where the contact lines of
the bearings converge inward), or "back to back"?

Almost certainly back to back.


I can order bearings that are ground and sold as a matching set in either "b
to b" or "f to f" that when mounted together and the retaining nut tightened
give a "light preload".

I can also order bearings that are not matched but are for "universal
pairing" that are about half the cost and are made to mount either way.
Some posts on the Yahoo Group mention that to apply a preload to these
bearings a shim is needed between them either on the inner or outer race,
others say none is needed. If the bearings are made to mount either way how
can they be preloaded without the use of a shim? If needed how thick should
it be?

You'll have to ask the bearing mfr for a definitive answer
on the spacer thickness, but I wouldn't recommend this
approach. A few tenths will make a big difference in the
preload, possibly resulting in overheating or loss of
rigidity, depending on whether the shim is too thick or too
thin. Best to buy the proper matching set of bearings. A
matched pair of precision 7207s should cost you around
$275.

Ned Simmons


Call Alpine Bearing in Boston. Ask for JC..get his quote before buying
from anyone else.

Gunner

"Pax Americana is a philosophy. Hardly an empire.
Making sure other people play nice and dont kill each other (and us)
off in job lots is hardly empire building, particularly when you give
them self determination under "play nice" rules.

Think of it as having your older brother knock the **** out of you
for torturing the cat." Gunner

On Sat, 03 Dec 2005 12:29:49 GMT, Gunner Asch
wrote:


2 days later..I had to replace a ballscrew and thrustbearing on a much
older machine made by the same manufacture. I pulled the bearing
housing apart on a lark..and found the bearings to be

I mentioned it to the customer..and he said he had always had an issue
doing a back turn.....

I suspect they really dont want to know about the second bearing I
found ..as it may open a can of worms they dont want opened. Shrug.

Gunner: Since when has that ever stopped you? Here's a P-38 C-Rat
Can Opener, go for it... :-P

"Dumbth" needs to be stomped out wherever and whenever you find it.
Even if you can't fix it, it's existence needs to become common
knowledge so other people can spot and avoid it.

But give the company a heads up, a chance to figure out there's a
potential problem with their old machines and to issue a service
bulletin about it - if you get up on a soap box, they're liable to
take offense and sic a lawyer or three on you.

A friend of mine (Not a FOAF) is a repair tech who found a
repeatable flaw in an automated stage light - if you called for a
certain combination of focus position, color filters and gobo screens,
the whole light would lock up solid in whatever position it was in,
and you had to remove power to get it to reset. If this happened in
the middle of a show, it could be a big problem.

The company's initial reaction was to deny there was any problem at
all, there's no way that could happen, yatta yatta yatta. Or at least
till they tried it themselves - then they got very very quiet... They
have since revised the operating firmware on the PROM two or three
times, and AFAIK they send them free to anyone who asks.

-- Bruce --

--
Bruce L. Bergman, Woodland Hills (Los Angeles) CA - Desktop
Electrician for Westend Electric - CA726700
5737 Kanan Rd. #359, Agoura CA 91301 (818) 889-9545
Spamtrapped address: Remove the python and the invalid, and use a net.

Terry Keeley wrote:
FWIW, the replacement bearings I ordered from Clausing a few years ago are
Fafnir 7205WN SU.




I have been following this thread with great interest, since I own the
same mill (http://www.abrasha.com/studio.htm).

I wonder, if I'll ever get to doing the same thing that you are doing.
Your mill is going to be as close to "new" as possible when you are
done. You even took the Clausing name plates on the side of the column
off. Now that is dedication!

And the added work you did by putting it all online is nothing to scoff
at either. What a great job you're doing.

BTW, I noticed in your images of the mill, that it does not have a motor
mounted. If you are thinking of getting a new motor for it, I strongly
recommend a new Baldor motor.

Get a 3 phase, 3/4HP with RIGID base. Whatever motor you may get, do
not get a resilient base motor for this mill. When I got my mill, it
had some crappy Sears 1/2HP resilient base motor on it (the one in the
picture on my site), and the mill was always dancing around the floor at
the higher rpm's. Let me know, and I'll post the model number of my motor.

Clausing still sells the rubber washers that go between the NEMA frame
and the motor for mounting. Now, with my new motor properly mounted the
machine is as rigid as it should be.

If you are interested, I have a parts list with prices from Clausing of
parts that are still available for this mill. The list is from the time
that I got my mill, so it is most likely at least be partially outdated.
I think that booklet also contained "exploded view" assembly drawings
of the mill. At the time I got my mill I bought this list with drawings
from Clausing for $10.00 after which I ordered several new parts. Among
other things I got two new nuts for the lead screws for the X and Y
axes, which brought the backlash down from around .020" to a more
manageable .010". Still not great, but then again I am not machining
parts for NASA. At the time new lead screws were also available, but
they cost more than I paid for the entire mill, so I did not get those.

And finally, I have printouts of the original owner's manual, that
someone emailed me when I got this mill. That might have been Mike
Henry, but I am not sure about that. I can no longer find the original
digital files that were sent to me. But I think, that I still have
those printouts somewhere, so if nothing else I can scan those and send
them to you.

Abrasha
http://www.abrasha.com

"Abrasha" wrote in message
. ..
Terry Keeley wrote:
FWIW, the replacement bearings I ordered from Clausing a few years ago
are
Fafnir 7205WN SU.




I have been following this thread with great interest, since I own the
same mill (http://www.abrasha.com/studio.htm).

I wonder, if I'll ever get to doing the same thing that you are doing.
Your mill is going to be as close to "new" as possible when you are done.
You even took the Clausing name plates on the side of the column off. Now
that is dedication!

And the added work you did by putting it all online is nothing to scoff at
either. What a great job you're doing.

BTW, I noticed in your images of the mill, that it does not have a motor
mounted. If you are thinking of getting a new motor for it, I strongly
recommend a new Baldor motor.

Get a 3 phase, 3/4HP with RIGID base. Whatever motor you may get, do not
get a resilient base motor for this mill. When I got my mill, it had some
crappy Sears 1/2HP resilient base motor on it (the one in the picture on
my site), and the mill was always dancing around the floor at the higher
rpm's. Let me know, and I'll post the model number of my motor.

Clausing still sells the rubber washers that go between the NEMA frame and
the motor for mounting. Now, with my new motor properly mounted the
machine is as rigid as it should be.

If you are interested, I have a parts list with prices from Clausing of
parts that are still available for this mill. The list is from the time
that I got my mill, so it is most likely at least be partially outdated. I
think that booklet also contained "exploded view" assembly drawings of the
mill. At the time I got my mill I bought this list with drawings from
Clausing for $10.00 after which I ordered several new parts. Among other
things I got two new nuts for the lead screws for the X and Y axes, which
brought the backlash down from around .020" to a more manageable .010".
Still not great, but then again I am not machining parts for NASA. At the
time new lead screws were also available, but they cost more than I paid
for the entire mill, so I did not get those.

And finally, I have printouts of the original owner's manual, that someone
emailed me when I got this mill. That might have been Mike Henry, but I
am not sure about that. I can no longer find the original digital files
that were sent to me. But I think, that I still have those printouts
somewhere, so if nothing else I can scan those and send them to you.

It probably wasn't me that sent you the manual as Clausing only charges $10
for it and I feel that all but the most destitute owners should be willing
to come with that much cash for a manual.

I may have sent you copies of the test report from my mill, though, or maybe
scans from an old brochure showing the few accessories they sold for these
mills. If you've lost those, or just want them, email me for a copy.

Mike

Call Alpine Bearing in Boston. Ask for JC..get his quote before buying
from anyone else.

Gunner



Thanks, I'll give him a try. I'm finding quite a variation in price for
essentially the same bearings. The SKF bearings were quoted at $265 by
Motion in Buffalo (or C$293 from Canadian Bearings here in Toronto) but the
Bardens are around $320 or an incredible C$512 here. Must be using our old
exchange rate of 60%!

Ive not removed bearings from your particular mill..but based on most
angular contact bearings...they should be mounted like this " "

With a hand snug preload.


Are you sure that's right? That symbology is for "face to face" mounting
and everyone I've talked to have said "back to back" is the way to go.

Just curious, are those angular contact bearings? I can't find those
numbers in the catalogue. The Fafnir numbers I'm getting are more like
2MM205WICRDUL, that's for a 25deg. Class 7 bearing.

You've got me - I'm no bearing expert.

It looks like they are a light duty (72), 25 mm (05), angular contact (WN)
bearing, external self-aligning (S) - but no mention of what the "U" might
stand for.


I'm actually finding that a 15degree contact angle might be better for a
milling machine as it can take higher radial loads with less deflection, 25
degree and up are better for axial loads.

I have been following this thread with great interest, since I own the
same mill (http://www.abrasha.com/studio.htm).

I wonder, if I'll ever get to doing the same thing that you are doing.
Your mill is going to be as close to "new" as possible when you are
done. You even took the Clausing name plates on the side of the column
off. Now that is dedication!

And the added work you did by putting it all online is nothing to scoff
at either. What a great job you're doing.

BTW, I noticed in your images of the mill, that it does not have a motor
mounted. If you are thinking of getting a new motor for it, I strongly
recommend a new Baldor motor.

Get a 3 phase, 3/4HP with RIGID base. Whatever motor you may get, do
not get a resilient base motor for this mill. When I got my mill, it
had some crappy Sears 1/2HP resilient base motor on it (the one in the
picture on my site), and the mill was always dancing around the floor at
the higher rpm's. Let me know, and I'll post the model number of my
motor.

Clausing still sells the rubber washers that go between the NEMA frame
and the motor for mounting. Now, with my new motor properly mounted the
machine is as rigid as it should be.

If you are interested, I have a parts list with prices from Clausing of
parts that are still available for this mill. The list is from the time
that I got my mill, so it is most likely at least be partially outdated.
I think that booklet also contained "exploded view" assembly drawings
of the mill. At the time I got my mill I bought this list with drawings
from Clausing for $10.00 after which I ordered several new parts. Among
other things I got two new nuts for the lead screws for the X and Y
axes, which brought the backlash down from around .020" to a more
manageable .010". Still not great, but then again I am not machining
parts for NASA. At the time new lead screws were also available, but
they cost more than I paid for the entire mill, so I did not get those.

And finally, I have printouts of the original owner's manual, that
someone emailed me when I got this mill. That might have been Mike
Henry, but I am not sure about that. I can no longer find the original
digital files that were sent to me. But I think, that I still have
those printouts somewhere, so if nothing else I can scan those and send
them to you.

Abrasha
http://www.abrasha.com

Thanks for the kind words, I've have two buddies that have this mill and
know what it's capable of. When shopping I looked hard at the "china
mills", including the RF45 but just couldn't do it, even though I would have
paid about the same as for this 1963 Clausing. It's going to be pretty as
well as functional soon.

I've got a new Leeson 1/2 HP to go on it, woulda used a 3/4 HP but this one
came cheap, not sure what you mean by a RIGID base but it has the standard
mounting frame.

Thanks for the offers on the parts lists but I ordered a manual and parts
lists as soon as I got the machine. I'm replacing all the bearings, the
gears for the knee and the "y" nut, plus a few other odds and ends. The
dealer I bought it from (Dick Treimstra in Detroit) even supplied an
original inspection report from another machine (might be Mike's) so I can
check mine when I'm done.

Terry Keeley wrote:


I've got a new Leeson 1/2 HP to go on it, woulda used a 3/4 HP but this one
came cheap, not sure what you mean by a RIGID base but it has the standard
mounting frame.


Check out this page: http://www.intea.hr/Baldor_pdf/ca453.pdf

Go to page 7 of 16. The photo is of a resilient base motor. AS you can
see, the base is a cradle that holds the motor around the shaft. On
both ends the motor is mounted in a thick rubber rings, which allows for
a certain amount of movement.

This is a rigid base motor: http://tinyurl.com/8vgzc The base is
welded to the motor.

Or look here http://www.leeson.com/products/techref/mechanical.htm
Read under: "Type of mounts"

Rigid base
Is bolted, welded or cast on main frame and allows motor to be rigidly
mounted on equipment.

Resilient base
Has isolation or resilient rings between motor mounting hubs and base to
absorb vibration and noise. A conductor is imbedded in the ring to
complete the circuit for grounding purposes.

Abrasha
http://www.abrasha.com

On Sat, 3 Dec 2005 22:44:51 -0500, "Terry Keeley" tkee(no
spam)@(or mail)rogers.com wrote:

Ive not removed bearings from your particular mill..but based on most
angular contact bearings...they should be mounted like this " "

With a hand snug preload.


Are you sure that's right? That symbology is for "face to face" mounting
and everyone I've talked to have said "back to back" is the way to go.


Lots of recommendations on which way to mount the bearings but no
input on why!

As I see it, if the angular contact bearings are the only
bearings on the shaft they should fit because that gives
radial location, end thrust location and maximum resistance to
angular misalignment of the shaft. By angular misalignment I mean
the axis of the shaft shifting so that the shaft centre line
traces out a double cone with the vertices located between the
two bearings. An appropriate case for this pairing arrangement
would be automobile front wheel bearings.

If,as is common, on a Mill or a Lathe a third bearing is fitted
well separated from the angular contact pair it is THIS bearing
that provides the primary resistance to shaft angular movement.
Any residual difference between this and the shaft angle defined
by the angular contact pair results in the shaft being over
constrained and generates large interbearing forces. This means
that the angular contact bearings shoud be mounted to minimise
the angular constraint - one way of visualising this is to
realise that this is half way to the geometry of a self aligning
bearing.

I am not a bearing expert but I think this is a reasonable way of
looking at it.

Jim

Oh, now see, don't think I've ever seen a resilient base motor, mines
definately a rigid base with the NEMA 56 frame. Thanks for the help!


"Abrasha" wrote in message
...
Terry Keeley wrote:


I've got a new Leeson 1/2 HP to go on it, woulda used a 3/4 HP but this
one
came cheap, not sure what you mean by a RIGID base but it has the
standard
mounting frame.


Check out this page: http://www.intea.hr/Baldor_pdf/ca453.pdf

Go to page 7 of 16. The photo is of a resilient base motor. AS you can
see, the base is a cradle that holds the motor around the shaft. On
both ends the motor is mounted in a thick rubber rings, which allows for
a certain amount of movement.

This is a rigid base motor: http://tinyurl.com/8vgzc The base is
welded to the motor.

Or look here http://www.leeson.com/products/techref/mechanical.htm
Read under: "Type of mounts"

Rigid base
Is bolted, welded or cast on main frame and allows motor to be rigidly
mounted on equipment.

Resilient base
Has isolation or resilient rings between motor mounting hubs and base to
absorb vibration and noise. A conductor is imbedded in the ring to
complete the circuit for grounding purposes.

Abrasha
http://www.abrasha.com

That's exactly the case with the 8520 spindle, they use a single bearing
near the top with a duplex pair at the bottom. Somewhere in my reading I
recall that back to back mounting is a more rigid set-up.



wrote in message
...
On Sat, 3 Dec 2005 22:44:51 -0500, "Terry Keeley" tkee(no
spam)@(or mail)rogers.com wrote:

Ive not removed bearings from your particular mill..but based on most
angular contact bearings...they should be mounted like this " "

With a hand snug preload.


Are you sure that's right? That symbology is for "face to face" mounting
and everyone I've talked to have said "back to back" is the way to go.


Lots of recommendations on which way to mount the bearings but no
input on why!

As I see it, if the angular contact bearings are the only
bearings on the shaft they should fit because that gives
radial location, end thrust location and maximum resistance to
angular misalignment of the shaft. By angular misalignment I mean
the axis of the shaft shifting so that the shaft centre line
traces out a double cone with the vertices located between the
two bearings. An appropriate case for this pairing arrangement
would be automobile front wheel bearings.

If,as is common, on a Mill or a Lathe a third bearing is fitted
well separated from the angular contact pair it is THIS bearing
that provides the primary resistance to shaft angular movement.
Any residual difference between this and the shaft angle defined
by the angular contact pair results in the shaft being over
constrained and generates large interbearing forces. This means
that the angular contact bearings shoud be mounted to minimise
the angular constraint - one way of visualising this is to
realise that this is half way to the geometry of a self aligning
bearing.

I am not a bearing expert but I think this is a reasonable way of
looking at it.

Jim

In article ,
says...
On Sat, 3 Dec 2005 22:44:51 -0500, "Terry Keeley" tkee(no
spam)@(or mail)rogers.com wrote:

Ive not removed bearings from your particular mill..but based on most
angular contact bearings...they should be mounted like this " "

With a hand snug preload.


Are you sure that's right? That symbology is for "face to face" mounting
and everyone I've talked to have said "back to back" is the way to go.


Lots of recommendations on which way to mount the bearings but no
input on why!

As I see it, if the angular contact bearings are the only
bearings on the shaft they should fit because that gives
radial location, end thrust location and maximum resistance to
angular misalignment of the shaft. By angular misalignment I mean
the axis of the shaft shifting so that the shaft centre line
traces out a double cone with the vertices located between the
two bearings. An appropriate case for this pairing arrangement
would be automobile front wheel bearings.

If,as is common, on a Mill or a Lathe a third bearing is fitted
well separated from the angular contact pair it is THIS bearing
that provides the primary resistance to shaft angular movement.
Any residual difference between this and the shaft angle defined
by the angular contact pair results in the shaft being over
constrained and generates large interbearing forces. This means
that the angular contact bearings shoud be mounted to minimise
the angular constraint - one way of visualising this is to
realise that this is half way to the geometry of a self aligning
bearing.

I am not a bearing expert but I think this is a reasonable way of
looking at it.

I assume by you mean back to back, but I think would be a better
notation. In the standard depiction of bearings the lines are drawn thru
the contact points between ball and races. For example...
http://www.koyousa.com/KoyoCatalog/C...&c=020-020-010

One way to think about which arrangement of two closely mounted angular
contact (or tapered roller) bearings is more rigid is to take the point
where the contact lines converge as the point the inner race would
rotate about if a moment perpendicular to the axis of the bearing is
applied to the inner race. Increasing the distance between the points
for a pair of bearings increases stiffness. I find this easier to
visualize by thinking first about tapered roller or spherical roller
bearings.

As far as the upper bearing on the spindle providing stiffness, you have
to consider that all bearings have some internal clearance, which is
specified independently of the precision class. The upper bearing will
resist an axial load applied to the spindle nose, but only once the load
is great enough to take up the clearance in the bearing, at which point
the axis of the spindle is sweeping out a small cone.

You can specify bearings with less than normal internal clearance, which
makes sense to me for the upper bearing in the sort of spindle we're
talking about. SKF uses the notation C0 for deep groove bearings with
minimal internal clearance, C3 is standard. I installed a C0 bearing in
my BP spindle when I replaced the bearings several years ago. I
experimented on the quill/spindle assembly a bit with an indicator and
spring scale before I reinstalled it, and as I recall, the results
agreed pretty well with the model I've described.

Ned Simmons

On Sun, 04 Dec 2005 11:28:44 +0000, wrote:

On Sat, 3 Dec 2005 22:44:51 -0500, "Terry Keeley" tkee(no
spam)@(or mail)rogers.com wrote:

Ive not removed bearings from your particular mill..but based on most
angular contact bearings...they should be mounted like this " "

With a hand snug preload.


Are you sure that's right? That symbology is for "face to face" mounting
and everyone I've talked to have said "back to back" is the way to go.


Lots of recommendations on which way to mount the bearings but no
input on why!

As I see it, if the angular contact bearings are the only
bearings on the shaft they should fit because that gives
radial location, end thrust location and maximum resistance to
angular misalignment of the shaft. By angular misalignment I mean
the axis of the shaft shifting so that the shaft centre line
traces out a double cone with the vertices located between the
two bearings. An appropriate case for this pairing arrangement
would be automobile front wheel bearings.

If,as is common, on a Mill or a Lathe a third bearing is fitted
well separated from the angular contact pair it is THIS bearing
that provides the primary resistance to shaft angular movement.
Any residual difference between this and the shaft angle defined
by the angular contact pair results in the shaft being over
constrained and generates large interbearing forces. This means
that the angular contact bearings shoud be mounted to minimise
the angular constraint - one way of visualising this is to
realise that this is half way to the geometry of a self aligning
bearing.

I am not a bearing expert but I think this is a reasonable way of
looking at it.

Jim
When you preload bearings..then put radical thrust loads on
it..which way does the off side bearing get pushed? Into or away from
the thrust?

Hardinge spindle bearings btw..are angular contact..and are mounted
with a preload cylinder between them. In the case of many or most
ballscrew thrust bearings with single end cartridges...they are inner
race to race as the pre-load cylinder.

Early Hardinges used 3 bearings..but all later ones..after the 1940s,
only used just the two, in th at configuration.

Gunner

"Pax Americana is a philosophy. Hardly an empire.
Making sure other people play nice and dont kill each other (and us)
off in job lots is hardly empire building, particularly when you give
them self determination under "play nice" rules.

Think of it as having your older brother knock the **** out of you
for torturing the cat." Gunner

On Sat, 3 Dec 2005 22:44:51 -0500, "Terry Keeley" tkee(no spam)@(or
mail)rogers.com wrote:

Ive not removed bearings from your particular mill..but based on most
angular contact bearings...they should be mounted like this " "

With a hand snug preload.


Are you sure that's right? That symbology is for "face to face" mounting
and everyone I've talked to have said "back to back" is the way to go.



Hopefully, either the inner races _or_ the outer races are clamped together
with a nut ant the other races are just located with a circlip, if at all. If
so, this will define which way round to mount the bearings since the clamping
_must_ set the preload.

If both inner and outer are clamped with nuts, then you are back to the
original confusion :-(



Mark Rand
RTFM

In article ,
says...
On Sat, 3 Dec 2005 22:44:51 -0500, "Terry Keeley" tkee(no spam)@(or
mail)rogers.com wrote:

Ive not removed bearings from your particular mill..but based on most
angular contact bearings...they should be mounted like this " "

With a hand snug preload.


Are you sure that's right? That symbology is for "face to face" mounting
and everyone I've talked to have said "back to back" is the way to go.



Hopefully, either the inner races _or_ the outer races are clamped together
with a nut ant the other races are just located with a circlip, if at all. If
so, this will define which way round to mount the bearings since the clamping
_must_ set the preload.

In the arrangement being discussed, both the inner and outer races are
clamped together. The nut does not set the preload, only clamps the
inner races together. The preload is predetermined at the factory by
grinding the faces of the races such that the faces are very slightly
offset when the bearing is assembled with zero preload. The proper
preload results from forcing the inner and outer races together.

Ned Simmons

In article ,
says...

When you preload

Can you explain that notation, please? Your post makes sense to me if
is face to face and is back to back, as illustrated here...
http://www.koyousa.com/KoyoCatalog/C...&c=020-020-010

I don't recall ever seeing that notation and it seems backwards from the
way bearings are usually drawn.

Ned Simmons

The inner races are clamped together with a locknut, is that the proper
condition for back to back mounting?



"Mark Rand" wrote in message
news
On Sat, 3 Dec 2005 22:44:51 -0500, "Terry Keeley" tkee(no spam)@(or
mail)rogers.com wrote:

Ive not removed bearings from your particular mill..but based on most
angular contact bearings...they should be mounted like this " "

With a hand snug preload.


Are you sure that's right? That symbology is for "face to face" mounting
and everyone I've talked to have said "back to back" is the way to go.



Hopefully, either the inner races _or_ the outer races are clamped
together
with a nut ant the other races are just located with a circlip, if at all.
If
so, this will define which way round to mount the bearings since the
clamping
_must_ set the preload.

If both inner and outer are clamped with nuts, then you are back to the
original confusion :-(



Mark Rand
RTFM

In article , no spam says...

The inner races are clamped together with a locknut, is that the proper
condition for back to back mounting?

For angular contact pairs, whether back to back or face to face,
the outer races and inner races *must* be clamped together.

The inners via the spindle nut and whatever spacers stack
happens to be there, the outers typically by clamping them
in a bored recess with a clamp ring.

In both ff and bb mounting, you will see that locknut. You cannot
determine a priori one vs the other because of its presence.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

Ned Simmons wrote:

In article ,
says...
On Sat, 3 Dec 2005 22:44:51 -0500, "Terry Keeley" tkee(no spam)@(or
mail)rogers.com wrote:

Ive not removed bearings from your particular mill..but based on most
angular contact bearings...they should be mounted like this " "

With a hand snug preload.


Are you sure that's right? That symbology is for "face to face" mounting
and everyone I've talked to have said "back to back" is the way to go.



Hopefully, either the inner races _or_ the outer races are clamped together
with a nut ant the other races are just located with a circlip, if at all. If
so, this will define which way round to mount the bearings since the clamping
_must_ set the preload.

In the arrangement being discussed, both the inner and outer races are
clamped together. The nut does not set the preload, only clamps the
inner races together. The preload is predetermined at the factory by
grinding the faces of the races such that the faces are very slightly
offset when the bearing is assembled with zero preload. The proper
preload results from forcing the inner and outer races together.

Ned Simmons

If you are using ultra precision bearings, Ned's information will work
fine. Also look for an identify mark on the inner and outer race of
each bearing. The inner race marks should be lined up on the shaft
and both outer marks should be lined up in the housing. The marks
represent the out of roundness of the bearing and the two bearing should
run with the out of roundness in the same position, to keep the run out
errors to a minimum. Of course the out of roundness you probably cant
even measure in most shops.( less than .0001)

John

Like most of you all, I save everything ...

Here are the bearing numbers I received when buying the bearings from
Clausing several years ago (I still have the empty boxes).

Two Fafnir 7205W SU bearings. The boxes were taped together and I
believe they were the lower spindle bearing.

Two Fafnir 9105KDD bearings. I believe these were for the front pulley.

One Fafnir 204KDD bearing. I believe this was the upper spindle bearing.

One CR Services 13548 Oil Seal. This is for the bottom of the spindle.


As the directions posted by Mike says, the bearings are Back-to-Back.
As I think back to when I was doing this, I recall putting them in
backwards first. The advantage of the back to back configuration is
when pressing the bearings out you are NOT reverse loading them. In the
face to face configuration you are loading one of the bearings in the
wrong direction when pressing them out. This might be a problem if the
press is high, and you want to reuse the bearings.

IAW my Fafnir catalog, the "SU" means the bearings are packaged singly,
and can be used DB, DF or DT (Tandem). "DU" in place of "SU" means you
will get 2 "SU" bearings in one package. Might be a price brake that way.

There is a difference between the "W" and the "WN" that Mike quoted. I
don't see a 7205WN in the catalog, just a 7205W. The "W" has a 20 deg
contact angle, and the WN would have a 40 deg. It is only the smaller
sizes that are "W", so I am guessing that they are to small to make with
a 40 deg angle.

FWIW, after I got the bearings from Clausing, I priced them out from a
bearing house and they were about a 1/3 cheaper.

Hope this helps.

Vince




Mike Henry wrote:



FWIW, the replacement bearings I ordered from Clausing a few years ago are
Fafnir 7205WN SU. I haven't installed them yet, but it looks like it might
be necessary pretty soon. There are one or two files in the Yahoo Clausing
group that describe bearing replacement, I think. I've archived off two
from there or elsewhere, complete with pictures. Email me if you can't find
them at the Yahoo group.

Following is the only info that Clausing could supply me on the spindle
(note that no "sample" was attached):

ASSEMBLING SPINDLE AND QUILL ASSEMBLY FOR CLAUSING MILL

1. Press 044-005 bearings one at a time on 701-004 spindle. Apply pressure
on inner race only and use DB mounting as shown in instructions supplied
with bearing - sample attached.


2.Slide 932-011 lock tab washer on spindle with inner tab in keyway.

3. Turn 537-020 nut on spindle and tighten securely against inner race of
bearing. Bend a tab on the 932-011 lock washer into a matching slot of the
537-020 nut.

4. Place the spindle in the 631-001 quill - 044-005 bearings in the threaded
end.


5. Press the 044-006 bearing on the spindle as far as it will go - apply
pressure on inner race only and support spindle on nose only.


6. Assembly 708-001 oil seal in 641-008 retainer as shown in attached
sketch.


7. Turn 641-008 retainer in quill -firm but not too tight.


8. Place M6-214 lead ball in threaded hole in quill and lock retainer with
#10-32 x 3/16" socket set screw.




INSTRUCTIONS FOR REMOVING NO.8520-25 V-MILL SPINDLE ASSEMBLY

1. Remove (2) 1/4" socket set screws from No.537-014 knurled nut located on
top of spindle, then remove knurl nut from spindle.


2. Remove (4) 1/4" machine screws (2 on each side of guard) which screws
guard No.342-020 to head casting. remove guard by pulling forward.

3. Remove (4) screws which screws plate No.386-009 containing pinion and
compound gears. Tap plate lightly on edge while prying outward with screw
driver to remove from dowell pins.


4. Remove socket set screw in No.233-001 dial and lift or pry up on stop
screw No.696-007 until top of screw is against spindle pulley, push quill to
bottom position.


5. Remove 1/4-20 socket cap screw holding stationary stop to face of quill.
With stop removed, remove quill assembly from head, reverse procedure to
install quill. Caution --be sure when installing spindle pulley guard that
brake lever is engaged in brake ring slot.

On Sun, 4 Dec 2005 17:29:16 -0500, Ned Simmons
wrote:

In article ,
says...

When you preload

Can you explain that notation, please? Your post makes sense to me if
is face to face and is back to back, as illustrated here...
http://www.koyousa.com/KoyoCatalog/C...&c=020-020-010

I don't recall ever seeing that notation and it seems backwards from the
way bearings are usually drawn.

Ned Simmons

As you will notice..angular contact bearings are essentally cone
shaped in their bearing contacts. One side of the bearing has a wide
gap around the race, the other side has a much narrower gap.

They are designed to basicly be pushed from the wide..or thrust side,
so the bearings are forced deeper in to the cone.

Hence the being two cones facing each other with the thrust towards
each other being applied by the shaft and lock nut that pulls them
deeper into their respective cones.

If you reverse the arraingment in a fashion..the shaft and nut
Pulls the inner races away from the cone. Even with a preload cylinder
between them..thrust makes the bearing move towards the wide end of
the cone..away from full contact.
\-----\
----- thrust------
/___/

Even if the two cones are seperated by a short distance..they are
pulled deeper in the races by the lock nut.

I dont know the nomenclature for front and back..but only know them as
thrust side and the other side G and the thrust side (often plainly
marked as such) need to be on the outside of the bearing stack, and
pulled together, then the entire bearing group held tightly in the
housing. Ball screw thrust bearing (double bearing) packs have a
removable "cover" that is held in place by bolts/screws that keep the
outer races held rigidly in place.often with a very thin spacer that
contacts only the facing faces G of the outer race.

Hope that helped, not confused..and that diagram in your link..is
as you indicated

Gunner

"Pax Americana is a philosophy. Hardly an empire.
Making sure other people play nice and dont kill each other (and us)
off in job lots is hardly empire building, particularly when you give
them self determination under "play nice" rules.

Think of it as having your older brother knock the **** out of you
for torturing the cat." Gunner