I came to examine another piece of garage sale acquisition:

http://www.flickr.com/photos/2768312...7608104743029/

The two pillow blocks are all part of a single casting which encloses two
ball bearings. There is a 5/8" shaft which on either side is reduced to 1/2"
and threaded 20 tpi, one side left and the other right handed. There is a
pulley in the middle like in the picture and an old v-belt around it so
someone had to have the shaft off in the past to put these on.

I can find no screws of any kind and cannot but conclude that the bearings
are press-fit into the housing. Interestingly, the shaft has a 1/16" or so
axial play within the race of the bearings but none when turning (there is
no slipping in the races).

The whole thing looked useful when I saw it and for $5 it seemed a steal.
Unfortunately, the right-hand end of the shaft has a minor bend in it. Also
the v-belt will need replacing so I cannot see my way past having to
disassemble the whole thing.

I have never taken ball bearings apart. I hit the Google and books yesterday
and am comfortable with the principles but, as with anything, God is in the
details:

1) Given the one piece construction, I shall have to hammer the shaft out of
both bearings simultaneously. Is there a way to make sure that the shaft
comes out rather than bearings with the shaft still attached? I can block up
one of the inner races but not both at the same time.

2) OTOH getting the shaft and bearings out as one unit may be a better way.
How does one make sure that this is what happens?

3) Any other helpful thoughts?

--
Michael Koblic,
Campbell River, BC

3) Any other helpful thoughts?

Michael Koblic,
Campbell River, BC


Michael

Absent some other disassembly method you will have to press the shaft.
Pesss the small shaft end and support the bearing housing as
necesssary. From prior experience I believe you will find the bearing
to housing not as tight a fit as the shaft to bearing. There also
might be shims for axial play involved. Buy new bearings before
disassembly. I would straighten the shaft using my lathe and heat as
needed.

Bob AZ

You have two pressed on shaft ends and two pressed in bearings. The fit
on either the inner or outer press fit will be much easier than the
other fit on the same end. Disassembly is the same: press from one end
until the other end bearing comes free of the housing. If the bearing
comes off the shaft easily, you are good, if not, put a collar on the
now free end and press the other direction.

You may or may not be able to straighten the shaft enough to get it to
run true. If you want to run buffing wheels, a bit of run out won't make
any difference.

Do NOT try to run this as a grinder wheel head. Lots of folks (like my
Dad!) did this but there is not wheel guard to contain a wheel explosion.

Michael Koblic wrote:
I came to examine another piece of garage sale acquisition:

http://www.flickr.com/photos/2768312...7608104743029/

The two pillow blocks are all part of a single casting which encloses two
ball bearings. There is a 5/8" shaft which on either side is reduced to 1/2"
and threaded 20 tpi, one side left and the other right handed. There is a
pulley in the middle like in the picture and an old v-belt around it so
someone had to have the shaft off in the past to put these on.

I can find no screws of any kind and cannot but conclude that the bearings
are press-fit into the housing. Interestingly, the shaft has a 1/16" or so
axial play within the race of the bearings but none when turning (there is
no slipping in the races).

The whole thing looked useful when I saw it and for $5 it seemed a steal.
Unfortunately, the right-hand end of the shaft has a minor bend in it. Also
the v-belt will need replacing so I cannot see my way past having to
disassemble the whole thing.

I have never taken ball bearings apart. I hit the Google and books yesterday
and am comfortable with the principles but, as with anything, God is in the
details:

1) Given the one piece construction, I shall have to hammer the shaft out of
both bearings simultaneously. Is there a way to make sure that the shaft
comes out rather than bearings with the shaft still attached? I can block up
one of the inner races but not both at the same time.

2) OTOH getting the shaft and bearings out as one unit may be a better way.
How does one make sure that this is what happens?

3) Any other helpful thoughts?

"Bob AZ" wrote in message
...

Absent some other disassembly method you will have to press the shaft.
Pesss the small shaft end and support the bearing housing as
necesssary. From prior experience I believe you will find the bearing
to housing not as tight a fit as the shaft to bearing. There also
might be shims for axial play involved. Buy new bearings before
disassembly. I would straighten the shaft using my lathe and heat as
needed.

This is where I get confused: If I press the shaft and support the housing
only I put a lot of strain on both bearings. If I understand you correctly
this is where the "buying new bearings" comes in, i.e. there is no way to
preserve the existing bearings?

Thanks.

"Michael Koblic" wrote in message
...
I came to examine another piece of garage sale acquisition:

http://www.flickr.com/photos/2768312...7608104743029/

The two pillow blocks are all part of a single casting which encloses two
ball bearings. There is a 5/8" shaft which on either side is reduced to
1/2" and threaded 20 tpi, one side left and the other right handed. There
is a pulley in the middle like in the picture and an old v-belt around it
so someone had to have the shaft off in the past to put these on.

I can find no screws of any kind and cannot but conclude that the bearings
are press-fit into the housing. Interestingly, the shaft has a 1/16" or so
axial play within the race of the bearings but none when turning (there is
no slipping in the races).

The whole thing looked useful when I saw it and for $5 it seemed a steal.
Unfortunately, the right-hand end of the shaft has a minor bend in it.
Also the v-belt will need replacing so I cannot see my way past having to
disassemble the whole thing.

I have never taken ball bearings apart. I hit the Google and books
yesterday and am comfortable with the principles but, as with anything,
God is in the details:

1) Given the one piece construction, I shall have to hammer the shaft out
of both bearings simultaneously. Is there a way to make sure that the
shaft comes out rather than bearings with the shaft still attached? I can
block up one of the inner races but not both at the same time.

2) OTOH getting the shaft and bearings out as one unit may be a better
way. How does one make sure that this is what happens?

3) Any other helpful thoughts?

--
Michael Koblic,
Campbell River, BC


Michael,
Try contacting one of these guys, they may have had to take one apart
before.
http://www.owwm.com/photoindex/detail.aspx?id=4990
or
http://www.owwm.com/photoindex/detail.aspx?id=7569

Good luck,
Paul

"RoyJ" wrote in message
...
You have two pressed on shaft ends and two pressed in bearings. The fit on
either the inner or outer press fit will be much easier than the other fit
on the same end. Disassembly is the same: press from one end until the
other end bearing comes free of the housing. If the bearing comes off the
shaft easily, you are good, if not, put a collar on the now free end and
press the other direction.

So if I understand correctly:
1) There is no way of predicting/ensuring which bearing pops first or even
if it is the shaft coming out of the bearing or the bearing out of the
housing
2) There is no way of protecting the other bearing, in fact both bearings
may be wirte-offs at the end of the procedure

You may or may not be able to straighten the shaft enough to get it to run
true. If you want to run buffing wheels, a bit of run out won't make any
difference.

I have not quite decided what to do with this. Any future use is kind of
predicated on ease or otherwise of disassembly/re-building etc. I even
wondered if one wanted a true shaft one could true it up in the assembly
itself (ruining the thread, naturally) by spinning the other end with a hand
drill and making like a lathe on the end in question with some sort of
makeshift tool post.

Do NOT try to run this as a grinder wheel head. Lots of folks (like my
Dad!) did this but there is not wheel guard to contain a wheel explosion.

That I have no intention to do. However, if I could get a 5/8-11 thread on
the end of the shaft somehow one could hook up one of the new cold-cutting
saw blades on it and spin it at the appropriate speed (I could even make a
guard for it :-).
Just (for most part) idle thoughts...

--
Michael Koblic,
Campbell River, BC

"Michael Koblic" wrote in message
...
I came to examine another piece of garage sale acquisition:

http://www.flickr.com/photos/2768312...7608104743029/

The two pillow blocks are all part of a single casting which encloses two
ball bearings. There is a 5/8" shaft which on either side is reduced to
1/2" and threaded 20 tpi, one side left and the other right handed. There
is a pulley in the middle like in the picture and an old v-belt around it
so someone had to have the shaft off in the past to put these on.

I can find no screws of any kind and cannot but conclude that the bearings
are press-fit into the housing. Interestingly, the shaft has a 1/16" or so
axial play within the race of the bearings but none when turning (there is
no slipping in the races).

The whole thing looked useful when I saw it and for $5 it seemed a steal.
Unfortunately, the right-hand end of the shaft has a minor bend in it.
Also the v-belt will need replacing so I cannot see my way past having to
disassemble the whole thing.

I have never taken ball bearings apart. I hit the Google and books
yesterday and am comfortable with the principles but, as with anything,
God is in the details:

1) Given the one piece construction, I shall have to hammer the shaft out
of both bearings simultaneously. Is there a way to make sure that the
shaft comes out rather than bearings with the shaft still attached? I can
block up one of the inner races but not both at the same time.

2) OTOH getting the shaft and bearings out as one unit may be a better
way. How does one make sure that this is what happens?

3) Any other helpful thoughts?

--
Michael Koblic,
Campbell River, BC


If you are primarily concerned about changing the belt, why not use a
replacement with links?

Correct but most of these come out without too much effort, shouldn't
hurt the bearings. If you have a small press, just ease them out.
Hammering should be avoided but has been done a lot of times. Since the
bearings are held in by the buffing wheels on each end, these are not
pressed on with the same forces that you would see on a critical
application eg rear axle shaft.



Michael Koblic wrote:
"RoyJ" wrote in message
...
You have two pressed on shaft ends and two pressed in bearings. The fit on
either the inner or outer press fit will be much easier than the other fit
on the same end. Disassembly is the same: press from one end until the
other end bearing comes free of the housing. If the bearing comes off the
shaft easily, you are good, if not, put a collar on the now free end and
press the other direction.

So if I understand correctly:
1) There is no way of predicting/ensuring which bearing pops first or even
if it is the shaft coming out of the bearing or the bearing out of the
housing
2) There is no way of protecting the other bearing, in fact both bearings
may be wirte-offs at the end of the procedure
You may or may not be able to straighten the shaft enough to get it to run
true. If you want to run buffing wheels, a bit of run out won't make any
difference.

I have not quite decided what to do with this. Any future use is kind of
predicated on ease or otherwise of disassembly/re-building etc. I even
wondered if one wanted a true shaft one could true it up in the assembly
itself (ruining the thread, naturally) by spinning the other end with a hand
drill and making like a lathe on the end in question with some sort of
makeshift tool post.
Do NOT try to run this as a grinder wheel head. Lots of folks (like my
Dad!) did this but there is not wheel guard to contain a wheel explosion.

That I have no intention to do. However, if I could get a 5/8-11 thread on
the end of the shaft somehow one could hook up one of the new cold-cutting
saw blades on it and spin it at the appropriate speed (I could even make a
guard for it :-).
Just (for most part) idle thoughts...

Those arbors are handy to have around for various uses. Many of those were
made with only bushing bearings, the deluxe ball bearing model is not all
that common to find IME.
Your housing has the extending tabs/slots to facilitate the installation of
wheel guards and tool rests.

The bent shaft is only a problem if you need to mount something on that
side, otherwise, you could add a shaft collar with a setscrew in it to
prevent the shaft from walking.

Using an incorrectly applied force could break or damage the housing, making
it a repair project, or just scrap.
Using a couple of plates the same length as the distance between the
bearings' inner races (or a length of pipe cut in half lengthwise) would
support the bearing spacing while attempting to remove the shaft with
cautiously applied force, if the shaft is not floating.

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


"Michael Koblic" wrote in message
...
I came to examine another piece of garage sale acquisition:

http://www.flickr.com/photos/2768312...7608104743029/

The two pillow blocks are all part of a single casting which encloses two
ball bearings. There is a 5/8" shaft which on either side is reduced to
1/2" and threaded 20 tpi, one side left and the other right handed. There
is a pulley in the middle like in the picture and an old v-belt around it
so someone had to have the shaft off in the past to put these on.

I can find no screws of any kind and cannot but conclude that the bearings
are press-fit into the housing. Interestingly, the shaft has a 1/16" or so
axial play within the race of the bearings but none when turning (there is
no slipping in the races).

The whole thing looked useful when I saw it and for $5 it seemed a steal.
Unfortunately, the right-hand end of the shaft has a minor bend in it.
Also the v-belt will need replacing so I cannot see my way past having to
disassemble the whole thing.

I have never taken ball bearings apart. I hit the Google and books
yesterday and am comfortable with the principles but, as with anything,
God is in the details:

1) Given the one piece construction, I shall have to hammer the shaft out
of both bearings simultaneously. Is there a way to make sure that the
shaft comes out rather than bearings with the shaft still attached? I can
block up one of the inner races but not both at the same time.

2) OTOH getting the shaft and bearings out as one unit may be a better
way. How does one make sure that this is what happens?

3) Any other helpful thoughts?

--
Michael Koblic,
Campbell River, BC

You can disregard part or all of the earlier post, now that I discovered
that the center section of the shaft is 5/8", and the beraing IDs would be
1/2".

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


"Michael Koblic" wrote in message
...
I came to examine another piece of garage sale acquisition:

http://www.flickr.com/photos/2768312...7608104743029/

The two pillow blocks are all part of a single casting which encloses two
ball bearings. There is a 5/8" shaft which on either side is reduced to
1/2" and threaded 20 tpi, one side left and the other right handed. There
is a pulley in the middle like in the picture and an old v-belt around it
so someone had to have the shaft off in the past to put these on.

I can find no screws of any kind and cannot but conclude that the bearings
are press-fit into the housing. Interestingly, the shaft has a 1/16" or so
axial play within the race of the bearings but none when turning (there is
no slipping in the races).

The whole thing looked useful when I saw it and for $5 it seemed a steal.
Unfortunately, the right-hand end of the shaft has a minor bend in it.
Also the v-belt will need replacing so I cannot see my way past having to
disassemble the whole thing.

I have never taken ball bearings apart. I hit the Google and books
yesterday and am comfortable with the principles but, as with anything,
God is in the details:

1) Given the one piece construction, I shall have to hammer the shaft out
of both bearings simultaneously. Is there a way to make sure that the
shaft comes out rather than bearings with the shaft still attached? I can
block up one of the inner races but not both at the same time.

2) OTOH getting the shaft and bearings out as one unit may be a better
way. How does one make sure that this is what happens?

3) Any other helpful thoughts?

--
Michael Koblic,
Campbell River, BC

"Wild_Bill" wrote in message
...
You can disregard part or all of the earlier post, now that I discovered
that the center section of the shaft is 5/8", and the beraing IDs would be
1/2".

Actually, I do not think they are. Looking at it closely the 5/8 to 1/2
shoulder occurs at the bearing and the inner race seems to be 5/8".

"Paul" wrote in message
...
Try contacting one of these guys, they may have had to take one apart
before.
http://www.owwm.com/photoindex/detail.aspx?id=4990
or
http://www.owwm.com/photoindex/detail.aspx?id=7569

Good luck,

This is impressive! How on earth did you get to these pictures?

"peter divergilio" wrote in message
...

If you are primarily concerned about changing the belt, why not use a
replacement with links?

That and the bent shaft...

"Wild_Bill" wrote in message
...
Those arbors are handy to have around for various uses. Many of those were
made with only bushing bearings, the deluxe ball bearing model is not all
that common to find IME.
Your housing has the extending tabs/slots to facilitate the installation
of wheel guards and tool rests.

The bent shaft is only a problem if you need to mount something on that
side, otherwise, you could add a shaft collar with a setscrew in it to
prevent the shaft from walking.

Using an incorrectly applied force could break or damage the housing,
making it a repair project, or just scrap.
Using a couple of plates the same length as the distance between the
bearings' inner races (or a length of pipe cut in half lengthwise) would
support the bearing spacing while attempting to remove the shaft with
cautiously applied force, if the shaft is not floating.

The bearings are deeply recessed on the inside and although I have not tried
it I have thought of this solution. I did not think, however, that I shall
be able to fit the supports sufficiently tightly between the bearings into
the recesses. Maybe if I cut a pipe with inner diameter of 5/8" both
*lengthwise* and *crosswise" then I could get each quarter in, position it
and stabilize it, somehow it might support both inner races.

That's why I love this group. You guys not only give me solutions, you make
me think about them...

On Oct 17, 1:58*pm, "Michael Koblic" wrote:
"Wild_Bill" wrote in message

Actually, I do not think they are. Looking at it closely the 5/8 *to 1/2
shoulder occurs at the bearing and the inner race seems to be 5/8".

Most ball bearings come in metric sizes. What is the number on the
bearing?

Dan

"Michael Koblic" wrote in message
...

"Paul" wrote in message
...
Try contacting one of these guys, they may have had to take one apart
before.
http://www.owwm.com/photoindex/detail.aspx?id=4990
or
http://www.owwm.com/photoindex/detail.aspx?id=7569

Good luck,

This is impressive! How on earth did you get to these pictures?


Do a Google search for general +milwaukee +"est 1930"
Paul

"Paul" wrote in message
...

"Michael Koblic" wrote in message
...

"Paul" wrote in message
...
Try contacting one of these guys, they may have had to take one apart
before.
http://www.owwm.com/photoindex/detail.aspx?id=4990
or
http://www.owwm.com/photoindex/detail.aspx?id=7569

Good luck,

This is impressive! How on earth did you get to these pictures?


Do a Google search for general +milwaukee +"est 1930"
Paul
There is always a better way :-)
BTW I contacted both guys who were very quick to respond but neither has
taken the piece apart.
The more I look at it the more I think it should be left well alone!

wrote in message
...
On Oct 17, 1:58 pm, "Michael Koblic" wrote:
"Wild_Bill" wrote in message

Actually, I do not think they are. Looking at it closely the 5/8 to 1/2
shoulder occurs at the bearing and the inner race seems to be 5/8".

Most ball bearings come in metric sizes. What is the number on the
bearing?

6202Z Asahi Japan

"Michael Koblic" wrote in message
...

wrote in message
...
On Oct 17, 1:58 pm, "Michael Koblic" wrote:
"Wild_Bill" wrote in message

Actually, I do not think they are. Looking at it closely the 5/8 to 1/2
shoulder occurs at the bearing and the inner race seems to be 5/8".

Most ball bearings come in metric sizes. What is the number on the
bearing?

6202Z Asahi Japan


A 6202Z bearing is a common metric deep groove ball bearing with a metal
shield on one side. ( the Z indicates a shield on one side and a ZZ after
the number indicates shields on both sides . An R indicates a polymer seal
and RR indicates sealed both sides)
It has an I.D.of 15 millimetres,an O.D. of 32 millimetres and a thickness of
9 millimetres. It should be readily available at any reasonably good
industrial supplier

On Sat, 18 Oct 2008 22:00:54 +1100, "Grumpy"
wrote:


"Michael Koblic" wrote in message
...

wrote in message
...
On Oct 17, 1:58 pm, "Michael Koblic" wrote:
"Wild_Bill" wrote in message

Actually, I do not think they are. Looking at it closely the 5/8 to 1/2
shoulder occurs at the bearing and the inner race seems to be 5/8".

Most ball bearings come in metric sizes. What is the number on the
bearing?

6202Z Asahi Japan


A 6202Z bearing is a common metric deep groove ball bearing with a metal
shield on one side. ( the Z indicates a shield on one side and a ZZ after
the number indicates shields on both sides . An R indicates a polymer seal
and RR indicates sealed both sides)
It has an I.D.of 15 millimetres,an O.D. of 32 millimetres and a thickness of
9 millimetres. It should be readily available at any reasonably good
industrial supplier


That's the 6002. The 6202 is 15mm id x 35mm od x 11mm width. I just
got done ordering one of each from Motion 2 days ago. I had to design
a little stub shaft to replace the Parr reactor seal on a lab reactor.
The Parr design depends on only one bearing, and runs on an o-ring
belt. I need to switch to an HTD belt, so I needed more side load
capability.

Pete Keillor

"Pete Keillor" wrote in message
...
On Sat, 18 Oct 2008 22:00:54 +1100, "Grumpy"
wrote:


"Michael Koblic" wrote in message
...

wrote in message
...
On Oct 17, 1:58 pm, "Michael Koblic" wrote:
"Wild_Bill" wrote in message

Actually, I do not think they are. Looking at it closely the 5/8 to 1/2
shoulder occurs at the bearing and the inner race seems to be 5/8".

Most ball bearings come in metric sizes. What is the number on the
bearing?

6202Z Asahi Japan


A 6202Z bearing is a common metric deep groove ball bearing with a metal
shield on one side. ( the Z indicates a shield on one side and a ZZ after
the number indicates shields on both sides . An R indicates a polymer seal
and RR indicates sealed both sides)
It has an I.D.of 15 millimetres,an O.D. of 32 millimetres and a thickness
of
9 millimetres. It should be readily available at any reasonably good
industrial supplier


That's the 6002. The 6202 is 15mm id x 35mm od x 11mm width. I just
got done ordering one of each from Motion 2 days ago. I had to design
a little stub shaft to replace the Parr reactor seal on a lab reactor.
The Parr design depends on only one bearing, and runs on an o-ring
belt. I need to switch to an HTD belt, so I needed more side load
capability.

Pete Keillor

Yep! You're right. I slipped down a couple of lines in the catalogue

On Thu, 16 Oct 2008 19:19:08 -0700, "Michael Koblic"
wrote:

I came to examine another piece of garage sale acquisition:

http://www.flickr.com/photos/2768312...7608104743029/

The two pillow blocks are all part of a single casting which encloses two
ball bearings. There is a 5/8" shaft which on either side is reduced to 1/2"
and threaded 20 tpi, one side left and the other right handed. There is a
pulley in the middle like in the picture and an old v-belt around it so
someone had to have the shaft off in the past to put these on.

I can find no screws of any kind and cannot but conclude that the bearings
are press-fit into the housing. Interestingly, the shaft has a 1/16" or so
axial play within the race of the bearings but none when turning (there is
no slipping in the races).

The whole thing looked useful when I saw it and for $5 it seemed a steal.
Unfortunately, the right-hand end of the shaft has a minor bend in it. Also
the v-belt will need replacing so I cannot see my way past having to
disassemble the whole thing.

I have never taken ball bearings apart. I hit the Google and books yesterday
and am comfortable with the principles but, as with anything, God is in the
details:

1) Given the one piece construction, I shall have to hammer the shaft out of
both bearings simultaneously. Is there a way to make sure that the shaft
comes out rather than bearings with the shaft still attached? I can block up
one of the inner races but not both at the same time.

2) OTOH getting the shaft and bearings out as one unit may be a better way.
How does one make sure that this is what happens?

3) Any other helpful thoughts?

Find a piece of allthread and two nuts. Put that in the "ears" on the
left side (belt side), adjust the nuts so it's quite snug. This is
to support the casting and keep it from flexing. The nuts go inside,
not outside.

Make a plate with a hole in it to support the piece but clear the
bottom end of the shaft. The hole should be slightly larger than the
OD of the shaft.

Press on other end of shaft with hydraulic press. The shaft should
move.

Don't hammer. Hammering can result in peening. Steady force is
better.

"Don Foreman" wrote in message
...
Find a piece of allthread and two nuts. Put that in the "ears" on the
left side (belt side), adjust the nuts so it's quite snug. This is
to support the casting and keep it from flexing. The nuts go inside,
not outside.

Make a plate with a hole in it to support the piece but clear the
bottom end of the shaft. The hole should be slightly larger than the
OD of the shaft.

Press on other end of shaft with hydraulic press. The shaft should
move.

Don't hammer. Hammering can result in peening. Steady force is
better.

If I understand you correctly the casing would be supported as well as the
bottom bearing but the top bearing would be sacrificed? Also I am not quite
sure what the "belt side" is: In this case the belt is looped in the middle
over a pulley, between the two bearings. Or do you mean that these things
are usually driven by a pulley on the left side?

On Oct 19, 5:08*pm, "Michael Koblic" wrote:
"Don Foreman" wrote in message

...

Find a piece of allthread and two nuts. *Put that in the "ears" on the
left side (belt side), *adjust the nuts so it's quite snug. *This is
to support the casting and keep it from flexing. *The nuts go inside,
not outside.

Make a plate with a hole in it to support the piece but clear the
bottom end of the shaft. * The hole should be slightly larger than the
OD of the shaft.

Press on other end of shaft with hydraulic press. *The shaft should
move.

Don't hammer. *Hammering can result in peening. *Steady force is
better.

If I understand you correctly the casing would be supported as well as the
bottom bearing but the top bearing would be sacrificed? Also I am not quite
sure what the "belt side" is:

I read it as the less well supported open side of the housing where
the belt moves in and out.

On Sun, 19 Oct 2008 14:08:37 -0700, "Michael Koblic"
wrote:



If I understand you correctly the casing would be supported as well as the
bottom bearing but the top bearing would be sacrificed?

Yes, unless the shaft wasn't all that tight in the bearing. That has
usually been the case in my experience.

Also I am not quite
sure what the "belt side" is: In this case the belt is looped in the middle
over a pulley, between the two bearings. Or do you mean that these things
are usually driven by a pulley on the left side?

The cross section of the casting is sort of a U in one plane. I refer
to the open end of the U.

"Grumpy" wrote in message
. au...

A 6202Z bearing is a common metric deep groove ball bearing with a metal
shield on one side. ( the Z indicates a shield on one side and a ZZ after
the number indicates shields on both sides . An R indicates a polymer seal
and RR indicates sealed both sides)
It has an I.D.of 15 millimetres,an O.D. of 32 millimetres and a thickness
of 9 millimetres. It should be readily available at any reasonably good
industrial supplier

I see. I went and found a Chinese catalogue with a search facility so I can
find the numbers and dimensions in future.
Now this may be a naive question but it puzzles me: A 5/8" shaft is 0.875 mm
or 0.034" thicker than 15 mm. This seems quite a lot. Do all shafts have to
be turned down to fit the bearings? The difference seems quite a lot to
reconcile by using just heat and cold for a press fit.

You would find out that a caliper is very handy to have for checking bearing
sizes.

Many (most) ball bearings are all metric, but some applications use a
combination of metric and inch dimensions, with inch used as the I.D.

Generic (or used domestic brand) calipers are available for about $20, even
for generic digital. Most digital calipers switch between metric and inch
for instant conversions, and also can be reset to zero at any point along
the beam.

Dial calipers are generally either metric, or inch, although there are some
that indicate both on a single tool.

Shafts and housing openings are machined to sizes which are appropriate for
the desired type of fit for ball bearings, otherwise bearing sizes are
selected to fit existing parts.

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


"Michael Koblic" wrote in message
...

"Grumpy" wrote in message
. au...

A 6202Z bearing is a common metric deep groove ball bearing with a metal
shield on one side. ( the Z indicates a shield on one side and a ZZ after
the number indicates shields on both sides . An R indicates a polymer
seal and RR indicates sealed both sides)
It has an I.D.of 15 millimetres,an O.D. of 32 millimetres and a thickness
of 9 millimetres. It should be readily available at any reasonably good
industrial supplier

I see. I went and found a Chinese catalogue with a search facility so I
can find the numbers and dimensions in future.
Now this may be a naive question but it puzzles me: A 5/8" shaft is 0.875
mm or 0.034" thicker than 15 mm. This seems quite a lot. Do all shafts
have to be turned down to fit the bearings? The difference seems quite a
lot to reconcile by using just heat and cold for a press fit.

"Wild_Bill" wrote in message
...
You would find out that a caliper is very handy to have for checking
bearing sizes.

Many (most) ball bearings are all metric, but some applications use a
combination of metric and inch dimensions, with inch used as the I.D.

Generic (or used domestic brand) calipers are available for about $20,
even for generic digital. Most digital calipers switch between metric and
inch for instant conversions, and also can be reset to zero at any point
along the beam.

Dial calipers are generally either metric, or inch, although there are
some that indicate both on a single tool.

Shafts and housing openings are machined to sizes which are appropriate
for the desired type of fit for ball bearings, otherwise bearing sizes are
selected to fit existing parts.


I am not sure that I get your point. Are you saying that the tolerances on
bearings are so loose that one has to get a handful and go through them with
a caliper to find which matches your shaft?

Looking through McMaster-Carr web site there seems to be a wealth of both
metric and imperial shafts as well as bearings. In my simple mind one would
use a 5/8" ID bearing for a 5/8" OD shaft. The tolerances quoted are 0.0003"
(converted from metric) for the bearing ID and 0.003" for the OD shaft
(worst case).

I am puzzled why in the case of this particular piece of equipment there are
15 mm ID bearings supporting a 5/8" shaft (measured in the middle with
calipers). To me it implies a degree of machining to achieve a fit, but why?

--
Michael Koblic,
Campbell River, BC

"Michael Koblic" wrote in message
...

"Wild_Bill" wrote in message
...
You would find out that a caliper is very handy to have for checking
bearing sizes.

Many (most) ball bearings are all metric, but some applications use a
combination of metric and inch dimensions, with inch used as the I.D.

Generic (or used domestic brand) calipers are available for about $20,
even for generic digital. Most digital calipers switch between metric and
inch for instant conversions, and also can be reset to zero at any point
along the beam.

Dial calipers are generally either metric, or inch, although there are
some that indicate both on a single tool.

Shafts and housing openings are machined to sizes which are appropriate
for the desired type of fit for ball bearings, otherwise bearing sizes
are selected to fit existing parts.


I am not sure that I get your point. Are you saying that the tolerances on
bearings are so loose that one has to get a handful and go through them
with a caliper to find which matches your shaft?

Looking through McMaster-Carr web site there seems to be a wealth of both
metric and imperial shafts as well as bearings. In my simple mind one
would use a 5/8" ID bearing for a 5/8" OD shaft. The tolerances quoted are
0.0003" (converted from metric) for the bearing ID and 0.003" for the OD
shaft (worst case).

I am puzzled why in the case of this particular piece of equipment there
are 15 mm ID bearings supporting a 5/8" shaft (measured in the middle with
calipers). To me it implies a degree of machining to achieve a fit, but
why?

--
Michael Koblic,
Campbell River, BC


It's really pretty simple. Ball bearings were originally designed to metric
dimensions because they were not developed in the USA or England and
millions of them were designed into products. The vast majority of them are
still made to metric dimensions although there are ones which are entirely
or partly inch dimensioned. The USA manufacturers commonly machined their
parts to fit the standard (metric) bearings. If you have a 5/8" shaft
running in a X202XX bearing, the shaft has been machined down to fit. There
has to be a shoulder of some kind to establish the axial location of the
shaft and bearing.

To remove the shaft you have to remove one bearing with it. The bearing will
slide out of the housing with a little force from the shaft, though there
may be a snap-ring or other retainer that has to be removed first. It is not
considered good practice to apply force thru the balls but often there is no
other way to remove the bearing. A light tap on the shaft end from a soft
faced hammer will usually do it. The bearing should be re-usable unless it
is corroded in the housing and a lot of force is necessary to get it out.

Don Young

On 2008-10-21, Michael Koblic wrote:

[ ... ]

I am not sure that I get your point. Are you saying that the tolerances on
bearings are so loose that one has to get a handful and go through them with
a caliper to find which matches your shaft?

If one went through them with a caliper, one would get very
frustrated trying to find variations in a given part number. You will
need something with a lot more resolution than a caliper can give you. :-)

Looking through McMaster-Carr web site there seems to be a wealth of both
metric and imperial shafts as well as bearings. In my simple mind one would
use a 5/8" ID bearing for a 5/8" OD shaft. The tolerances quoted are 0.0003"
(converted from metric) for the bearing ID and 0.003" for the OD shaft
(worst case).

And you expect to measure 0.0003" variations with a caliper?

I am puzzled why in the case of this particular piece of equipment there are
15 mm ID bearings supporting a 5/8" shaft (measured in the middle with
calipers). To me it implies a degree of machining to achieve a fit, but why?

There is a very good reason for this -- which the maker of an
early double-sided 5.25" floppy drive did not understand. He mounted
the spindle in a pair of flanged outer race bearings which slipped into
a cylindrical bore. On one end of the shaft was the cup which drove the
floppy. On the other end was simply a tapped hole. (1/4" shaft, FWIW).
They slipped a pulley over the end of the shaft, and tightened a screw
and washer to hold the drive pulley onto the shaft. They then painted
over the end with Glyptol.

Some months later, I was finding double density floppies very
difficult to read, while single density was still easy. Pulling off the
drive belt, I discovered cogging in the spindle.

The bearings were radial thrust bearings, and the tightening of
the screw had put axial thrust on them, causing them to wear out quite
rapidly. When I got new bearings for the drive, I spent a little time
on the lathe and turned up a spacer to go around the shaft between the
bearings, and to hold them just a tiny bit farther apart than the
cylinder in which the outer races mounted would do. This allowed me to
tighten the screw firmly enough to keep the pulley from slipping without
putting a serious axial load on the bearings.

In the case of your assembly, the 15mm shaft is turned down to
5/16" so the bearings will slide onto the shaft and then stop at a
certain position. The reason for this is that there are some parts
missing from your device which press against the outside end of the
inner race, and support the wheel or buffer -- held in position by the
nuts being tightened against a washer to hold the outer surface of the
wheel or buffer.

Without that step in diameter from 5/8" to 15mm, this tightening
would put a serious axial load on the bearings. Your bearings were made
for radial thrust only. You *could* use angular thrust, but to take the
various loads, they would need to be larger and more expensive. The
full 15mm diameter of the inner portion of the shaft provides a spacer
for the inner races so you can tighten the nuts as much as needed.

I suspect that you will find a step in the bore where the OD of
the bearings mounts, to keep them from moving too far towards the
center. Fairly light pressing should move the far bearing out of its
bore, and the shaft inwards through the inner race on the near side.
You will need to find a setscrew on the pulley to allow you to release
it from the shaft.

Note that you will need to use a lathe to make the spacers
between the outside end of the bearings and the wheels or buffers before
you can use this. I doubt that you will be able to find the parts
needed, as they are made for the task at hand. I have similar things on
two grinders with built-in motors. They have similar steps on the
shafts to keep the ball bearing assemblies from being pressed in too far
and suffering similar fates.

Perhaps someone who has the same model can measure and draw up
what you need to make. But you still need to make a new shaft to get
around the bent end.

Good Luck,
DoN.

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

On Mon, 20 Oct 2008 18:24:46 -0700, "Michael Koblic"
wrote:


"Wild_Bill" wrote in message
...
You would find out that a caliper is very handy to have for checking
bearing sizes.

Many (most) ball bearings are all metric, but some applications use a
combination of metric and inch dimensions, with inch used as the I.D.

Generic (or used domestic brand) calipers are available for about $20,
even for generic digital. Most digital calipers switch between metric and
inch for instant conversions, and also can be reset to zero at any point
along the beam.

Dial calipers are generally either metric, or inch, although there are
some that indicate both on a single tool.

Shafts and housing openings are machined to sizes which are appropriate
for the desired type of fit for ball bearings, otherwise bearing sizes are
selected to fit existing parts.


I am not sure that I get your point. Are you saying that the tolerances on
bearings are so loose that one has to get a handful and go through them with
a caliper to find which matches your shaft?

Bearing tolerances are very tight measured in microns. Check out
http://www.ntnamerica.com/pdf/2200/tolrance.pdf to see.

Looking through McMaster-Carr web site there seems to be a wealth of both
metric and imperial shafts as well as bearings. In my simple mind one would
use a 5/8" ID bearing for a 5/8" OD shaft. The tolerances quoted are 0.0003"
(converted from metric) for the bearing ID and 0.003" for the OD shaft
(worst case).

I am puzzled why in the case of this particular piece of equipment there are
15 mm ID bearings supporting a 5/8" shaft (measured in the middle with
calipers). To me it implies a degree of machining to achieve a fit, but why?

I would imagine it was machined down to allow a shoulder to press the
bearing inner race against. Most applications with a rotating shaft
have a slip fit on the outer race and a press fit on the inner race.
Check out these sites for info on shaft and housing design and shaft
and housing fit. http://www.ntnamerica.com/pdf/2200/shaftdes.pdf
http://www.ntnamerica.com/pdf/2200/brgfits.pdf

I would not suggest reusing the bearings. They're pretty cheap and
readily available and it's not worth the risk. I'm going from memory
but I think you stated this was a 6202Z? If so, it most likely has two
shields so you would need to order a 6202ZZ. The 6202Z is normally
stamped on the shield because the factory doesn't know if it will be
used in a single or double shield application. If you order with one Z
you will only get a single shield. Good luck.

I didn't mean to suggest that ball bearings were individually hand selected
from batches of bearings to achieve the correct fit.

A more-common all metric dimension bearing would likely be cheaper than a
metric bearing with an inch I.D. in most cases.
If the manufacturer had size and strength constraints a less common bearing
may be more suitable.

When machine manufacturers are designing their parts that the bearings will
mount/mate to, they will typically machine their shaft and housing
dimensions to match a commonly available bearing.

When GLU (guys like us or maintenance/repair folks) are working
with/repairing existing machines, the bearing mating parts are first
measured, then an appropriate, commonly available (with any luck) bearing is
ordered/selected to fit the application.

As you can see by the other responses, the buffing arbor shaft was machined
for several reasons. Positioning the shaft's length relative to the arbor's
housing primarily, and to fit the bearings' I.D.s, and to use common
mounting hardware.. 1/2" nuts.
The shaft remains stronger in the center (providing shoulders for the
bearings), utilizing a commonly available pulley I.D., held in place
laterally, and commonly available mounting hardware for the mounted
accessories.

If the shaft were just 1/2" diameter, shaft collars or some similar hardware
that wouldn't compromise the shaft strength would be required to lock or
locate the shaft in place (more hardware generally means higher
manufacturing cost), and the bearings would've been more expensive.

The arbor manufacturer had a responsibility to market a fairly safe product,
one that wouldn't fly apart, safe enough for a DIY-type to take home and
use.

There are ball bearings that have integral locking features for securing the
inner races to shafts, but they are more expensive than an ordinary ball
bearing assembly.

The machining that was performed on the arbor shaft wasn't an expensive
operation, performed on automated machines it was probably completed in
probably less than a minute from raw barstock to a finished, threaded part.

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


"Michael Koblic" wrote in message
...

"Wild_Bill" wrote in message
...

snippage

Shafts and housing openings are machined to sizes which are appropriate
for the desired type of fit for ball bearings, otherwise bearing sizes
are selected to fit existing parts.


I am not sure that I get your point. Are you saying that the tolerances on
bearings are so loose that one has to get a handful and go through them
with a caliper to find which matches your shaft?

Looking through McMaster-Carr web site there seems to be a wealth of both
metric and imperial shafts as well as bearings. In my simple mind one
would use a 5/8" ID bearing for a 5/8" OD shaft. The tolerances quoted are
0.0003" (converted from metric) for the bearing ID and 0.003" for the OD
shaft (worst case).

I am puzzled why in the case of this particular piece of equipment there
are 15 mm ID bearings supporting a 5/8" shaft (measured in the middle with
calipers). To me it implies a degree of machining to achieve a fit, but
why?

--
Michael Koblic,
Campbell River, BC

"Wild_Bill" wrote in message
...
I didn't mean to suggest that ball bearings were individually hand selected
from batches of bearings to achieve the correct fit.

A more-common all metric dimension bearing would likely be cheaper than a
metric bearing with an inch I.D. in most cases.
If the manufacturer had size and strength constraints a less common
bearing may be more suitable.

When machine manufacturers are designing their parts that the bearings
will mount/mate to, they will typically machine their shaft and housing
dimensions to match a commonly available bearing.

When GLU (guys like us or maintenance/repair folks) are working
with/repairing existing machines, the bearing mating parts are first
measured, then an appropriate, commonly available (with any luck) bearing
is ordered/selected to fit the application.

As you can see by the other responses, the buffing arbor shaft was
machined for several reasons. Positioning the shaft's length relative to
the arbor's housing primarily, and to fit the bearings' I.D.s, and to use
common mounting hardware.. 1/2" nuts.
The shaft remains stronger in the center (providing shoulders for the
bearings), utilizing a commonly available pulley I.D., held in place
laterally, and commonly available mounting hardware for the mounted
accessories.

If the shaft were just 1/2" diameter, shaft collars or some similar
hardware that wouldn't compromise the shaft strength would be required to
lock or locate the shaft in place (more hardware generally means higher
manufacturing cost), and the bearings would've been more expensive.

The arbor manufacturer had a responsibility to market a fairly safe
product, one that wouldn't fly apart, safe enough for a DIY-type to take
home and use.

There are ball bearings that have integral locking features for securing
the inner races to shafts, but they are more expensive than an ordinary
ball bearing assembly.

The machining that was performed on the arbor shaft wasn't an expensive
operation, performed on automated machines it was probably completed in
probably less than a minute from raw barstock to a finished, threaded
part.

Who knew that such a simple piece of equipment would provide so many lessons
in engineering and associated history and economics? Thanks everybody for
such a detailed explanation. Some of the links provided are useful as
reference. Again, my Google technique has proved deficient as I have been
looking for them or something similar without success for the last two
weeks.

In the final analysis the whole thing cost me $5 and most of the procedures
suggested seem to involve greater costs than I can justify at present. I
shall just keep looking at it 'cos it's pretty and an idea for good use will
come to me in time :-)

--
Michael Koblic,
Campbell River, BC

In the final analysis the whole thing cost me $5 and most of the procedures
suggested seem to involve greater costs than I can justify at present. I
shall just keep looking at it 'cos it's pretty and an idea for good use will
come to me in time :-)

--
Michael Koblic,
Campbell River, BC- Hide quoted text -

- Show quoted text -

Michael

Lots of education and a great experience and for only $5.00. Now get
brave and take it apart and straighten the shaft and reassemble it.
And put the arbor to use.

Bob AZ