Tim Wescott wrote:

Well, I'm having one of those nice reverse-midas days when everything I
touch turns to dog doo.

Plan D was to finish milling out some dihedral braces for an
almost-ready-to-fly kit that I'm building. After setting everything up
and turning on the switch I find that the spindle on my Smithy 3-in-1
machine's milling head won't turn.

The spindle rides in tapered bearings in the quill, which are adjusted
by a round nut. The sheet metal retainer for the nut either never got
bent into place to prevent the nut from turning or it bent itself out of
the way. The bearings were way too tight -- to the point where there's
some bluing of the spindle on the bottom end. The grease in the
bearings has obviously overheated and left each roller bedded in it's
own little custom-made varnish pocket.

So I have two questions:

For the short term, is there anything that'll likely dissolve this
varnish? I can scrape it off the outer races with my fingernails, but
the rollers are retained onto the inner races & I can't get to it. I'd
like to soak it off if possible, although I may just leave things fairly
loose & make my dang cut to get through today.

For the longer term, how much of a chance is there that I can get these
bearings from a local bearing house? Should I just be applying to
Smithy for new ones? If I'm going to go to the trouble of pulling those
outer races I darn well want to put in decent bearings rather than
Chinese crap.

Thankee much.

Oh, and while I'm sure that the grease in there was of the finest
possible quality, I somehow inadvertently scraped it all off and threw
it away in a moment of distraction. Should I just replace it with
regular old automotive bearing grease, or is there something better?

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

I would bet you that good old brake cleaner will cut the old grease just
fine - you can spray some into a container and soak the bearings.
Automotive wheel bearing grease sees a very similar load profile - while I
am not a grease expert, my inclination would be to use a high pressure type
automotive bearing grease, or maybe the short fiber grease (do they still
make that?)
"Tim Wescott" wrote in message
...
Tim Wescott wrote:

Well, I'm having one of those nice reverse-midas days when everything I
touch turns to dog doo.

Plan D was to finish milling out some dihedral braces for an
almost-ready-to-fly kit that I'm building. After setting everything up
and turning on the switch I find that the spindle on my Smithy 3-in-1
machine's milling head won't turn.

The spindle rides in tapered bearings in the quill, which are adjusted by
a round nut. The sheet metal retainer for the nut either never got bent
into place to prevent the nut from turning or it bent itself out of the
way. The bearings were way too tight -- to the point where there's some
bluing of the spindle on the bottom end. The grease in the bearings has
obviously overheated and left each roller bedded in it's own little
custom-made varnish pocket.

So I have two questions:

For the short term, is there anything that'll likely dissolve this
varnish? I can scrape it off the outer races with my fingernails, but
the rollers are retained onto the inner races & I can't get to it. I'd
like to soak it off if possible, although I may just leave things fairly
loose & make my dang cut to get through today.

For the longer term, how much of a chance is there that I can get these
bearings from a local bearing house? Should I just be applying to Smithy
for new ones? If I'm going to go to the trouble of pulling those outer
races I darn well want to put in decent bearings rather than Chinese
crap.

Thankee much.

Oh, and while I'm sure that the grease in there was of the finest possible
quality, I somehow inadvertently scraped it all off and threw it away in a
moment of distraction. Should I just replace it with regular old
automotive bearing grease, or is there something better?

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

william_b_noble wrote:

I would bet you that good old brake cleaner will cut the old grease just
fine - you can spray some into a container and soak the bearings.
Automotive wheel bearing grease sees a very similar load profile - while I
am not a grease expert, my inclination would be to use a high pressure type
automotive bearing grease, or maybe the short fiber grease (do they still
make that?)
"Tim Wescott" wrote in message
...

snip

I had been eying my bucket of carb cleaner -- I dumped the bearings in
for the mere 30 minutes recommended and they cleaned right up.

I think I'll use the bearing grease that I have in my grease gun -- at
this point I'm kinda considering that those bearings are 1/2 way to
being toast anyway, so there's probably a teardown in that mill head's
future.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

william_b_noble wrote:
I would bet you that good old brake cleaner will cut the old grease just
fine - you can spray some into a container and soak the bearings.

Brake cleaner seems to come in at least two formulations. The one I
like is 50/50 Acetone/Xylol(Xylene). This, IMHO, is a better solvent
than either alone. I buy the Acetone and Xylol from a large paint store
in gallon cans and mix them myself. I pour them into a ShueShot sprayer
(available from KBC, Travers, ...). This sprayer is pressurised with
_clean_ shop air. Besides being "environmentaly friendly" this is MUCH
cheaper than buying aerosol cans of break cleaner.

An other one that I don't particularly like is perchloroetylene and
Methylene Chloride.

Ted

On Mon, 29 Aug 2005 21:14:48 -0700, the blithe spirit Tim Wescott
clearly indicated:

I had been eying my bucket of carb cleaner -- I dumped the bearings in
for the mere 30 minutes recommended and they cleaned right up.

I think I'll use the bearing grease that I have in my grease gun -- at
this point I'm kinda considering that those bearings are 1/2 way to
being toast anyway, so there's probably a teardown in that mill head's
future.

You done did a baaaaaad thing, Tim. Those oil-based solvents leach
into the metal and take forever to come out, usually with heat when
the bearing is spinning, effectively neutralizing the grease. Doesn't
that sound like great fun? I heard warnings about it in tech school
and again when I worked for Palomar Technology, a vibration tester
manufacturer for predictive maintenance firms. "Spectacular" is when a
30' steam turbine is running at top speed and a bearing seizes.

I'd heat and spray (NOT soak) those bearings with a film-free,
evaporative solvent before putting them back into service if they were
mine. YMMV.

--
Like they say, 99% of lawyers give the rest a bad name.
------------------------------------------------------
http://diversify.com Lawyer-free Website Development

Tim Wescott wrote:
william_b_noble wrote:

I would bet you that good old brake cleaner will cut the old grease
just fine - you can spray some into a container and soak the bearings.
Automotive wheel bearing grease sees a very similar load profile -
while I am not a grease expert, my inclination would be to use a high
pressure type automotive bearing grease, or maybe the short fiber
grease (do they still make that?)

Yes, but it's hard to find. It is sometimes called "Drum brake wheel
bearing grease". Plews or possibly Lubrimatic.

I had been eying my bucket of carb cleaner -- I dumped the bearings in
for the mere 30 minutes recommended and they cleaned right up.

I'd caution that some ball bearings use a plastic separator between the
individual balls. That plastic may not like strong solvents.

I think I'll use the bearing grease that I have in my grease gun -- at
this point I'm kinda considering that those bearings are 1/2 way to
being toast anyway, so there's probably a teardown in that mill head's
future.

Rex B wrote:

Tim Wescott wrote:

william_b_noble wrote:

I would bet you that good old brake cleaner will cut the old grease
just fine - you can spray some into a container and soak the
bearings. Automotive wheel bearing grease sees a very similar load
profile - while I am not a grease expert, my inclination would be to
use a high pressure type automotive bearing grease, or maybe the
short fiber grease (do they still make that?)


Yes, but it's hard to find. It is sometimes called "Drum brake wheel
bearing grease". Plews or possibly Lubrimatic.

I had been eying my bucket of carb cleaner -- I dumped the bearings in
for the mere 30 minutes recommended and they cleaned right up.


I'd caution that some ball bearings use a plastic separator between the
individual balls. That plastic may not like strong solvents.

I think I'll use the bearing grease that I have in my grease gun -- at
this point I'm kinda considering that those bearings are 1/2 way to
being toast anyway, so there's probably a teardown in that mill head's
future.

All these warnings come too late!

The separator is sheet metal -- I wouldn't have dumped the bearings into
paint-stripping parts cleaner otherwise. I guess I'll spray the
bearings with starting fluid (ether) to wash out what grease I can, then
heat them gently and let them outgas.

Since I'm reclaiming them instead of replacing them I was planning on
monitoring their health in any case -- I'll just do that ever much more so.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

In article ,
Larry Jaques says...
On Mon, 29 Aug 2005 21:14:48 -0700, the blithe spirit Tim Wescott
clearly indicated:

I had been eying my bucket of carb cleaner -- I dumped the bearings in
for the mere 30 minutes recommended and they cleaned right up.

I think I'll use the bearing grease that I have in my grease gun -- at
this point I'm kinda considering that those bearings are 1/2 way to
being toast anyway, so there's probably a teardown in that mill head's
future.

You done did a baaaaaad thing, Tim. Those oil-based solvents leach
into the metal and take forever to come out, usually with heat when
the bearing is spinning, effectively neutralizing the grease. Doesn't
that sound like great fun? I heard warnings about it in tech school
and again when I worked for Palomar Technology, a vibration tester
manufacturer for predictive maintenance firms.

I think you're being a bit alarmist here, Larry. If there
is such an effect it's likely only a factor in very
critical applications - I've never heard of it in over 20
years of designing and working around rolling bearings.
SKF, NSK, and Klueber (mfr of fancy lubricants) all
recommend rinsing bearings in hydrocarbon solvents, with no
warning about avoiding any specific solvents.

"Spectacular" is when a
30' steam turbine is running at top speed and a bearing seizes.

The rotors of all the steam turbines I'm aware of run in
hydrodynamic bearings. I'd be interested in any info you
might have on medium to large turbines equipped with
rolling bearings.

Re the OP, I think my biggest concern would be the bluing
of the bearings indicating overheating.

Tim: If you post the part numbers from the bearings we can
likely give you some idea of the cost of replacements.

Ned Simmons

On Tue, 30 Aug 2005 11:39:03 -0400, the blithe spirit Ned Simmons
clearly indicated:

I think you're being a bit alarmist here, Larry. If there
is such an effect it's likely only a factor in very
critical applications -

Yes, perhaps for a Smithy bearing...


I've never heard of it in over 20
years of designing and working around rolling bearings.
SKF, NSK, and Klueber (mfr of fancy lubricants) all
recommend rinsing bearings in hydrocarbon solvents, with no
warning about avoiding any specific solvents.

I'm surprised since I heard about it from two vastly different
user sets of bearings. Then again, designers and repairmen work
in two entirely different fields/worlds. Could we know something
you don't? I'm positive that you know things we don't.

What are the absorptive factors in bearing race material?


"Spectacular" is when a
30' steam turbine is running at top speed and a bearing seizes.

The rotors of all the steam turbines I'm aware of run in
hydrodynamic bearings. I'd be interested in any info you
might have on medium to large turbines equipped with
rolling bearings.

You could be right there. I don't know that it was a roller bearing
which seized, but a guy from SDG&E's Encina Power Plant was at PTI one
day (ca. 1990) discussing the horror stories of machinery failures
with the engineers and I had the opportunity to listen in. Scary!

PTI was absorbed by SKF, and the potential resultant corporate
climate was what made me take my leave. They closed the Carlsbad, CA
plant, moving all to the other absorbed company in Kearney Mesa
(northern San Diego suburb), about 2 extra hours in gawdawful traffic
each day for me. Test technicians aren't paid enough to want to go
that extra mile for the company. sigh

--
Like they say, 99% of lawyers give the rest a bad name.
------------------------------------------------------
http://diversify.com Lawyer-free Website Development

Ned Simmons wrote:


Re the OP, I think my biggest concern would be the bluing
of the bearings indicating overheating.

That bugs the hell out of me, too. The bearings themselves aren't blue,
it's the quill in the vicinity of the lower bearing -- would this be
because the bearings were embedded in grease and had no air contact? I
dunno.

Tim: If you post the part numbers from the bearings we can
likely give you some idea of the cost of replacements.

Ned Simmons

The Smithy chart gives their own part numbers -- S20500 & S20410, but
the chart also has a column of "generic" numbers, in which the bearings
are listed as "D2007107" & "2007106". I have to admit to focusing so
tightly on diagnosing the problem that the fact that I may have had the
reference I needed didn't fully penetrate -- it was just that sort of
day yesterday.

I wasn't clear on my original question, which was how likely would it be
that I could waltz into a bearing place with bearings in hand but no
other information and get decent replacements. If the bearing numbers
mean anything, though, then I know I'm set.

My intention would be to get a set of bearings that are one or two
grades better than what's indicated in the Smithy part number, unless
they're already claiming to use really good bearings.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Tim Wescott wrote:
The separator is sheet metal -- I wouldn't have dumped the bearings into
paint-stripping parts cleaner otherwise. I guess I'll spray the
bearings with starting fluid (ether) to wash out what grease I can, then
heat them gently and let them outgas.

Use 50/50 Xylol/Acetone. I have a ShureShot sprayer which is presurised
with shop air and another with mineral spirits (paint thinner). The X/A
is a very effective solvent.

Ted

Tim Wescott wrote:
The separator is sheet metal -- I wouldn't have dumped the bearings into
paint-stripping parts cleaner otherwise. I guess I'll spray the
bearings with starting fluid (ether) to wash out what grease I can, then
heat them gently and let them outgas.

Ether should not be a problem. Chem-Dip or similar carb cleaner
definitely gets into the pores and seeps out for a long time.
Once in my mis-guided youth, I elected to use carb cleaner to
reclaim a big aluminum percolator with strong carb dip cleaner. This was
back in the 1970s before all that EPA and OSHA silliness. Got the pot
clean, but after about a week of strange-tasting.... make that
AWFUL-tasting! ...coffee, we abandoned that pot.

In article ,
says...
Ned Simmons wrote:


Re the OP, I think my biggest concern would be the bluing
of the bearings indicating overheating.

That bugs the hell out of me, too. The bearings themselves aren't blue,
it's the quill in the vicinity of the lower bearing -- would this be
because the bearings were embedded in grease and had no air contact? I
dunno.

That would be my guess. But if the spindle runs true you
might leave well enough alone and watch it closely. Bearing
steel will tolerate relatively high temps without loss of
mechanical properties, around 400F IIRC. I believe
distortion is often a problem before the bearing reaches
the temperature where its temper is affected.


Tim: If you post the part numbers from the bearings we can
likely give you some idea of the cost of replacements.

Ned Simmons

The Smithy chart gives their own part numbers -- S20500 & S20410, but
the chart also has a column of "generic" numbers, in which the bearings
are listed as "D2007107" & "2007106". I have to admit to focusing so
tightly on diagnosing the problem that the fact that I may have had the
reference I needed didn't fully penetrate -- it was just that sort of
day yesterday.

Check for numbers on the bearings as well. I suspect the
7107 and 7106 indicate these bearings are extra-light
angular contact bearings, which also fits with the
application. That would make the smaller of the two, the
7106, 30 ID x 55 OD x 13 W. The 7107 would be 35 x 62 x 14.
Can we assume that there is a single 7107 at the nose of
the spindle, and the 7106 is at the upper end? Or does the
"D" (for "duplex"?) on the 7107 indicate a pair?

If the bearings are angular contact bearings, one shoulder
of the races will be higher than the other. The balls and
cage may or may not be separable from the races, but,
unlike normal radial bearings, there will be considerable
play in the bearings when they're unmounted.


I wasn't clear on my original question, which was how likely would it be
that I could waltz into a bearing place with bearings in hand but no
other information and get decent replacements. If the bearing numbers
mean anything, though, then I know I'm set.

My intention would be to get a set of bearings that are one or two
grades better than what's indicated in the Smithy part number, unless
they're already claiming to use really good bearings.


Price will be much higher for precision bearings. Probably
around $20 each for standard, and around $150 for ABEC 7,
which is what you'll find in Bridgeport spindles, for
example. Regular ABEC 1 bearings from the big mfrs (SKF,
NSK, etc.) are so good these days it may be worth trying
them before spending the big bucks on the precision
bearings, unless you have a matched pair of bearings at the
spindle nose.

Ned Simmons

In article ,
Larry Jaques says...
On Tue, 30 Aug 2005 11:39:03 -0400, the blithe spirit Ned Simmons
clearly indicated:

I think you're being a bit alarmist here, Larry. If there
is such an effect it's likely only a factor in very
critical applications -

Yes, perhaps for a Smithy bearing...


I've never heard of it in over 20
years of designing and working around rolling bearings.
SKF, NSK, and Klueber (mfr of fancy lubricants) all
recommend rinsing bearings in hydrocarbon solvents, with no
warning about avoiding any specific solvents.

I'm surprised since I heard about it from two vastly different
user sets of bearings. Then again, designers and repairmen work
in two entirely different fields/worlds. Could we know something
you don't?

Absolutely. I often worry that after I've designed, built,
and installed a new piece of equipment that the folks who
actually have to live with it every day are cursing me
behind my back. I'd much rather have the feedback, even if
it's negative, and a chance to improve things and avoid
repeating a mistake in the future.

I'm positive that you know things we don't.

What are the absorptive factors in bearing race material?

I wonder if rather than a matter of absorption, it's a case
of contamination by solvents that don't evaporate
completely?. Klueber seems to recommend some pretty
aggressive and volatile solvents in preference to mineral
spirits or kerosene, which they warn about leaving a
residue.



"Spectacular" is when a
30' steam turbine is running at top speed and a bearing seizes.

The rotors of all the steam turbines I'm aware of run in
hydrodynamic bearings. I'd be interested in any info you
might have on medium to large turbines equipped with
rolling bearings.

You could be right there. I don't know that it was a roller bearing
which seized, but a guy from SDG&E's Encina Power Plant was at PTI one
day (ca. 1990) discussing the horror stories of machinery failures
with the engineers and I had the opportunity to listen in. Scary!

I've done a bit of work for GE's medium steam turbine
division over the years and have some second hand knowledge
of how elaborate the oil supply systems for the bearings in
turbines can be, particularly on naval vessels. It's very
obvious that keeping those bearings happy is paramount.

Ned Simmons

Ned Simmons wrote:

In article ,
says...

Ned Simmons wrote:
- snip -

The Smithy chart gives their own part numbers -- S20500 & S20410, but
the chart also has a column of "generic" numbers, in which the bearings
are listed as "D2007107" & "2007106". I have to admit to focusing so
tightly on diagnosing the problem that the fact that I may have had the
reference I needed didn't fully penetrate -- it was just that sort of
day yesterday.


Check for numbers on the bearings as well. I suspect the
7107 and 7106 indicate these bearings are extra-light
angular contact bearings, which also fits with the
application. That would make the smaller of the two, the
7106, 30 ID x 55 OD x 13 W. The 7107 would be 35 x 62 x 14.
Can we assume that there is a single 7107 at the nose of
the spindle, and the 7106 is at the upper end? Or does the
"D" (for "duplex"?) on the 7107 indicate a pair?

If the bearings are angular contact bearings, one shoulder
of the races will be higher than the other. The balls and
cage may or may not be separable from the races, but,
unlike normal radial bearings, there will be considerable
play in the bearings when they're unmounted.

Without going out to the shop and looking the sizes sound right. If by
"one shoulder higher" you mean the races (and rollers) are conical like
a wheel bearing in a car then yes, they are. In this case the cages and
inner races are married and the outer races are free (well, pressed into
the quill, at the moment). I'm sure this was so they could make the
bearing tension adjustable without spending big bucks on matched duplex
bearings. The big bearing is _not_ a duplex, but maybe it was in some
previous design.

I wasn't clear on my original question, which was how likely would it be
that I could waltz into a bearing place with bearings in hand but no
other information and get decent replacements. If the bearing numbers
mean anything, though, then I know I'm set.

My intention would be to get a set of bearings that are one or two
grades better than what's indicated in the Smithy part number, unless
they're already claiming to use really good bearings.



Price will be much higher for precision bearings. Probably
around $20 each for standard, and around $150 for ABEC 7,
which is what you'll find in Bridgeport spindles, for
example. Regular ABEC 1 bearings from the big mfrs (SKF,
NSK, etc.) are so good these days it may be worth trying
them before spending the big bucks on the precision
bearings, unless you have a matched pair of bearings at the
spindle nose.

Ned Simmons

Thanks Ned. Right now I just want to get this thing back together so I
can make my cut. I've printed your post out and will keep it with the
machine if & when I ever buy bearings for it.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

In article ,
says...
Ned Simmons wrote:

In article ,
says...

Ned Simmons wrote:
- snip -

The Smithy chart gives their own part numbers -- S20500 & S20410, but
the chart also has a column of "generic" numbers, in which the bearings
are listed as "D2007107" & "2007106". I have to admit to focusing so
tightly on diagnosing the problem that the fact that I may have had the
reference I needed didn't fully penetrate -- it was just that sort of
day yesterday.


Without going out to the shop and looking the sizes sound right. If by
"one shoulder higher" you mean the races (and rollers) are conical like
a wheel bearing in a car then yes, they are.

Tapered roller bearings? Ignore everything I said, except
perhaps the stuff about how the heat may have affected the
bearings. It looks like your 2007106 crosses to an SKF
32006X (30×55×17mm). D2007107 = SKF 32007X (35×62×18mm).
Precision class for tapered roller bearings is very
confusing, and the run of the mill bearings are generally
much less accurate than ABEC 1 ball bearings.

Ned Simmons

On Tue, 30 Aug 2005 16:01:35 -0400, the blithe spirit Ned Simmons
clearly indicated:

In article ,
Larry Jaques says...

I'm surprised since I heard about it from two vastly different
user sets of bearings. Then again, designers and repairmen work
in two entirely different fields/worlds. Could we know something
you don't?

Absolutely. I often worry that after I've designed, built,
and installed a new piece of equipment that the folks who
actually have to live with it every day are cursing me
behind my back. I'd much rather have the feedback, even if
it's negative, and a chance to improve things and avoid
repeating a mistake in the future.

You're a good man, Ned.


I'm positive that you know things we don't.

What are the absorptive factors in bearing race material?

I wonder if rather than a matter of absorption, it's a case
of contamination by solvents that don't evaporate
completely?. Klueber seems to recommend some pretty
aggressive and volatile solvents in preference to mineral
spirits or kerosene, which they warn about leaving a
residue.

OK. How are bearing races made? Do they have any pores to catch
grease/solvent at all? If so, how much?


I've done a bit of work for GE's medium steam turbine
division over the years and have some second hand knowledge
of how elaborate the oil supply systems for the bearings in
turbines can be, particularly on naval vessels. It's very
obvious that keeping those bearings happy is paramount.

Ayup, broken pieces of large-diameter spinny metal things might go
quite a distance before something solid stopped them. I'd imagine that
hydro power plant generators and turbines might be the same way. I
definitely wouldn't want to be around one when it let go, whether it
was a bearing or something solid hitting a turbine blade. =:-0


--
"Given the low level of competence among politicians,
every American should become a Libertarian."
-- Charley Reese, Alameda Times-Star (California), June 17, 2003

In article ,
Larry Jaques says...


What are the absorptive factors in bearing race material?

I wonder if rather than a matter of absorption, it's a case
of contamination by solvents that don't evaporate
completely?. Klueber seems to recommend some pretty
aggressive and volatile solvents in preference to mineral
spirits or kerosene, which they warn about leaving a
residue.

OK. How are bearing races made? Do they have any pores to catch
grease/solvent at all? If so, how much?

In the process I've seen for high volume bearings, the
races are roughed out of tubular stock on multi-spindle
automatics, heat treated, then finish ground. Great care is
taken with the finish and surface condition, but at some
level there is obviously some roughness, so I suppose some
residual solvent could be trapped. But I'm inclined to
believe that contamination as a result of incomplete
evaporation of the cleaning agent is more likely. I thought
you might be alluding to this in your original reply to Tim
when you recommended spraying them off with an "evaporative
solvent."

Ned Simmons

On Wed, 31 Aug 2005 23:55:22 -0400, the blithe spirit Ned Simmons
clearly indicated:

In article ,
Larry Jaques says...

OK. How are bearing races made? Do they have any pores to catch
grease/solvent at all? If so, how much?

In the process I've seen for high volume bearings, the
races are roughed out of tubular stock on multi-spindle
automatics, heat treated, then finish ground. Great care is
taken with the finish and surface condition, but at some
level there is obviously some roughness, so I suppose some
residual solvent could be trapped. But I'm inclined to
believe that contamination as a result of incomplete
evaporation of the cleaning agent is more likely. I thought
you might be alluding to this in your original reply to Tim
when you recommended spraying them off with an "evaporative
solvent."

I was, to some extent, but I thought they might be more porous
than I than that. (More like a sintered metal.)

..-.
Life is short. Eat dessert first!
---
http://diversify.com Comprehensive Website Development