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Michael Koblic March 13th 09 12:53 AM

Electric motor shafts
 
In an effort to educate myself and hopefully gain a 3/4" shaft in the
process I attacked an electric motor I bought for $1 in a garage sale. It
has seen better days. I suspect it powered some sort of woodworking machine
as the whole thing was coated liberally with sawdust inside and out. The
insulation was rotten and falling off the wires. I should mention that
physically it was a big beast but only 1/2hp (the label was barely
readable).

I managed to get the front off. I expected ball bearings supporting the
shaft but there were sleeve bearings at both ends - the front one quite
chewed up which surprised me as the shaft seemed to turn freely. The oiling
port was plugged with sawdust.

I got the fan off and tried to get the rotor off but could not even shift
it. I should say I have never attempted anything similar and use of Workmate
and sledge hammer is probably not the recommended method. I managed to
mushroom the end of the shaft nicely but the rotor would not shift.

The rotor sits on the central part of the shaft which is 1.25" as opposed to
the ends which are 0.75". There appears to be a small key in a slot but
trying to punch it out did not meet with success either.

Questions:

1) Are sleeve bearings usual in electric motors or is this some old, cheap
model?
2) Are shafts in such motor usually machined in one piece or is a 3/4" shaft
rammed into a mandrel to hold the rotor? In spite copious cleaning I cannot
tell for sure.
3) I am puzzled at the inability to shift the rotor. If the sledge hammer
did not do the job is a gear puller (or some other gizmo) likely to succeed
(as well as protect the shaft, of course)?
4) Am I missing some method by which the rotor is held onto the shaft
rendering the sledge hammer ineffective?

Books and Google have been no help. Neither was liberal application of
Liquid Wrench.

Thanks,

--
Michael Koblic,
Campbell River, BC



Buerste March 13th 09 01:20 AM

Electric motor shafts
 

"Michael Koblic" wrote in message
...
In an effort to educate myself and hopefully gain a 3/4" shaft in the
process I attacked an electric motor I bought for $1 in a garage sale. It
has seen better days. I suspect it powered some sort of woodworking
machine as the whole thing was coated liberally with sawdust inside and
out. The insulation was rotten and falling off the wires. I should mention
that physically it was a big beast but only 1/2hp (the label was barely
readable).

I managed to get the front off. I expected ball bearings supporting the
shaft but there were sleeve bearings at both ends - the front one quite
chewed up which surprised me as the shaft seemed to turn freely. The
oiling port was plugged with sawdust.

I got the fan off and tried to get the rotor off but could not even shift
it. I should say I have never attempted anything similar and use of
Workmate and sledge hammer is probably not the recommended method. I
managed to mushroom the end of the shaft nicely but the rotor would not
shift.

The rotor sits on the central part of the shaft which is 1.25" as opposed
to the ends which are 0.75". There appears to be a small key in a slot but
trying to punch it out did not meet with success either.

Questions:

1) Are sleeve bearings usual in electric motors or is this some old, cheap
model?
2) Are shafts in such motor usually machined in one piece or is a 3/4"
shaft rammed into a mandrel to hold the rotor? In spite copious cleaning I
cannot tell for sure.
3) I am puzzled at the inability to shift the rotor. If the sledge hammer
did not do the job is a gear puller (or some other gizmo) likely to
succeed (as well as protect the shaft, of course)?
4) Am I missing some method by which the rotor is held onto the shaft
rendering the sledge hammer ineffective?

Books and Google have been no help. Neither was liberal application of
Liquid Wrench.

Thanks,

--
Michael Koblic,
Campbell River, BC


Can you get your $1 back?



RoyJ March 13th 09 02:59 AM

Electric motor shafts
 
1) properly lubed sleeve bearing have a longer service life in certain
applications like furnace blowers. In the 'old' days, they were used in
the majority of motors since ball bearings had both shorter life and
were much more expensive.

2) Rotors have a steel shaft pressed through a stack of laminations made
from a high silcon steel. The stuff is extremely hard and brittle.
Easily bites into a normal steel shaft.

3) If you try pressing the shaft the way it was pressed on, you MIGHT
have a chance. Smashing it with a hammer won't do the job. Gear puller
is not even an option.

Michael Koblic wrote:
In an effort to educate myself and hopefully gain a 3/4" shaft in the
process I attacked an electric motor I bought for $1 in a garage sale. It
has seen better days. I suspect it powered some sort of woodworking machine
as the whole thing was coated liberally with sawdust inside and out. The
insulation was rotten and falling off the wires. I should mention that
physically it was a big beast but only 1/2hp (the label was barely
readable).

I managed to get the front off. I expected ball bearings supporting the
shaft but there were sleeve bearings at both ends - the front one quite
chewed up which surprised me as the shaft seemed to turn freely. The oiling
port was plugged with sawdust.

I got the fan off and tried to get the rotor off but could not even shift
it. I should say I have never attempted anything similar and use of Workmate
and sledge hammer is probably not the recommended method. I managed to
mushroom the end of the shaft nicely but the rotor would not shift.

The rotor sits on the central part of the shaft which is 1.25" as opposed to
the ends which are 0.75". There appears to be a small key in a slot but
trying to punch it out did not meet with success either.

Questions:

1) Are sleeve bearings usual in electric motors or is this some old, cheap
model?
2) Are shafts in such motor usually machined in one piece or is a 3/4" shaft
rammed into a mandrel to hold the rotor? In spite copious cleaning I cannot
tell for sure.
3) I am puzzled at the inability to shift the rotor. If the sledge hammer
did not do the job is a gear puller (or some other gizmo) likely to succeed
(as well as protect the shaft, of course)?
4) Am I missing some method by which the rotor is held onto the shaft
rendering the sledge hammer ineffective?

Books and Google have been no help. Neither was liberal application of
Liquid Wrench.

Thanks,


Ignoramus20387 March 13th 09 03:30 AM

Electric motor shafts
 
On 2009-03-13, RoyJ wrote:
1) properly lubed sleeve bearing have a longer service life in certain
applications like furnace blowers. In the 'old' days, they were used in
the majority of motors since ball bearings had both shorter life and
were much more expensive.


What about modern balll bearings?
i

Michael Koblic March 13th 09 05:23 AM

Electric motor shafts
 

"Buerste" wrote in message
...

Can you get your $1 back?


No, and I would not want to. The motor came with two pulleys attached, one
of them 3-step. As the new ones would cost me about $25 I consider myself
$24 ahead not including the 3 hours of amusement I have had so far with the
motor :-)



Buerste March 13th 09 05:48 AM

Electric motor shafts
 

"Michael Koblic" wrote in message
...

"Buerste" wrote in message
...

Can you get your $1 back?


No, and I would not want to. The motor came with two pulleys attached, one
of them 3-step. As the new ones would cost me about $25 I consider myself
$24 ahead not including the 3 hours of amusement I have had so far with
the motor :-)


We have a WINNER!

The rotor was seriously pressed on that shaft, you probably won't get it
off. Bronze bearings have a lot of good points. If kept lubed they last a
very long time.



Buerste March 13th 09 05:50 AM

Electric motor shafts
 

"Ignoramus20387" wrote in message
...
On 2009-03-13, RoyJ wrote:
1) properly lubed sleeve bearing have a longer service life in certain
applications like furnace blowers. In the 'old' days, they were used in
the majority of motors since ball bearings had both shorter life and
were much more expensive.


What about modern balll bearings?
i


I want some of those modern balll bearings, I only can get old fashioned
ball bearings...lucky *******!



Jim Wilkins March 13th 09 12:05 PM

Electric motor shafts
 
On Mar 12, 8:53*pm, "Michael Koblic" wrote:
In an effort to educate myself and hopefully gain a 3/4" shaft in the
process I attacked an electric motor I bought for $1 in a garage sale. It
has seen better days. I suspect it powered some sort of woodworking machine
as the whole thing was coated liberally with sawdust inside and out. The
insulation was rotten and falling off the wires. I should mention that
physically it was a big beast but only 1/2hp (the label was barely
readable).

I managed to get the front off. I expected ball bearings supporting the
shaft but there were sleeve bearings at both ends - the front one quite
chewed up which surprised me as the shaft seemed to turn freely. The oiling
port was plugged with sawdust.

I got the fan off and tried to get the rotor off but could not even shift
it. I should say I have never attempted anything similar and use of Workmate
and sledge hammer is probably not the recommended method. I managed to
mushroom the end of the shaft nicely but the rotor would not shift.

The rotor sits on the central part of the shaft which is 1.25" as opposed to
the ends which are 0.75". There appears to be a small key in a slot but
trying to punch it out did not meet with success either.

Questions:

1) Are sleeve bearings usual in electric motors or is this some old, cheap
model?
2) Are shafts in such motor usually machined in one piece or is a 3/4" shaft
rammed into a mandrel to hold the rotor? In spite copious cleaning I cannot
tell for sure.
3) I am puzzled at the inability to shift the rotor. If the sledge hammer
did not do the job is a gear puller (or some other gizmo) likely to succeed
(as well as protect the shaft, of course)?
4) Am I missing some method by which the rotor is held onto the shaft
rendering the sledge hammer ineffective?

Books and Google have been no help. Neither was liberal application of
Liquid Wrench.

Thanks,

--
Michael Koblic,
Campbell River, BC


The Workmate doesn't have enough inertia to restrain the armature. You
need to back it with a hunk of iron at least as heavy as the sledge
hammer. A long piece of heavy pipe might work if your collection of
scrap metal is inadequate.

Think of the toy with a line of suspended balls, hit one end and only
the far one swings out. Or bucking a rivet.

Jim Wilkins

Wild_Bill March 13th 09 02:03 PM

Electric motor shafts
 
I think that a more effective way to remove the shaft would be making a saw
cut into the rotor toward and inline with the shaft centerline.
I haven't tried this, but I wouldn't think that it would be necessary to
make more than one cut to release the contact pressure between the rotor and
shaft.

Silicon steel used for motor and tranformer laminations, that I'm familiar
with has been very soft steel, and not at all diffiult to cut.
The difference of an induction motor rotor is that there are the steel
laminations surrounded by a cast aluminum alloy (which is what makes up the
windings, or current paths, similar to a copper wound armature).
I believe the aluminum alloy would prohibit the use of an abrasive disk to
cut thru the rotor material.

I don't think that trying to drive a shaft out with a hammer will produce
much effect on the position of the rotor.

Polished sleeve bearings are very practical for numerous applications
(provided that they are lubricated properly). There might be an very
noticeable opening in the sleeve, referred to sometimes as the window, and
many motor housings will have an arrow or other indication of where the
window is located so the installer can apply the side load to a location
where the window is opposite the load side. The oil wick material might
contact the shaft thru the window for continuous lubrication.

On some older domestic USA motors, the manufacturer may have used cast end
end bells for the motor end plates that are very similar for both sleeve and
ball bearing models.
For the ball bearing models, they eliminate the extra material used for the
sleeve model, and machine a counterbore/pocket for the ball bearing
assembly.
This means that if a HSM discovers a good motor with worn sleeve bearings,
he can sometimes machine away the sleeve support webs in the end bell
castings to install ball bearings.
I've done this just to see if it could be done, and the results were as good
as if the motor originally had ball bearings.

This modification wasn't difficult to perform on a 9" lathe with 4-jaw
chuck, and the the cost of the bearings was only a few dollars.

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


"Michael Koblic" wrote in message
...
In an effort to educate myself and hopefully gain a 3/4" shaft in the
process I attacked an electric motor I bought for $1 in a garage sale. It
has seen better days. I suspect it powered some sort of woodworking
machine as the whole thing was coated liberally with sawdust inside and
out. The insulation was rotten and falling off the wires. I should mention
that physically it was a big beast but only 1/2hp (the label was barely
readable).

I managed to get the front off. I expected ball bearings supporting the
shaft but there were sleeve bearings at both ends - the front one quite
chewed up which surprised me as the shaft seemed to turn freely. The
oiling port was plugged with sawdust.

I got the fan off and tried to get the rotor off but could not even shift
it. I should say I have never attempted anything similar and use of
Workmate and sledge hammer is probably not the recommended method. I
managed to mushroom the end of the shaft nicely but the rotor would not
shift.

The rotor sits on the central part of the shaft which is 1.25" as opposed
to the ends which are 0.75". There appears to be a small key in a slot but
trying to punch it out did not meet with success either.

Questions:

1) Are sleeve bearings usual in electric motors or is this some old, cheap
model?
2) Are shafts in such motor usually machined in one piece or is a 3/4"
shaft rammed into a mandrel to hold the rotor? In spite copious cleaning I
cannot tell for sure.
3) I am puzzled at the inability to shift the rotor. If the sledge hammer
did not do the job is a gear puller (or some other gizmo) likely to
succeed (as well as protect the shaft, of course)?
4) Am I missing some method by which the rotor is held onto the shaft
rendering the sledge hammer ineffective?

Books and Google have been no help. Neither was liberal application of
Liquid Wrench.

Thanks,

--
Michael Koblic,
Campbell River, BC



RoyJ March 13th 09 02:36 PM

Electric motor shafts
 
Current ball bearings are made to better tolerances than older ones. The
ABEC numbers (higher is better) have stayed the same but a 30 year old
ABEC-3 is pretty close to a current ABEC-1. And even the import specials
are pretty good.

Ball bearings are good for higher speed and lower friction. Sleeve
bearings are good for lower speeds, higher average loads, but have
slightly higher friction (means heat in the bearing). A sleeve bearing
actually floats on a film of oil (assuming it's properly lubed) so there
is no metal to metal contact. Ball bearing have metal to metal contact
because the balls squeeze the lube out of the point of contact.
Everything is hardened but there is still the wear factor.

Sleeve bearings take severe impact loadings better. The relevant surface
area of a 3/4" shaft is around 1/2" wide. Compare that to the 3 or 4
ball point contacts in a ball bearing. Of course a roller bearing has
much more contact area, they are used for the high impact applications.

I have some bearing balls out of a race car CV joint that show nasty
cratering under a 10x magnification. You can see rows of chips taken out
of the hardened surface, look almost like the gouge marks from a backhoe
tooth on a concrete road surface.

Ignoramus20387 wrote:
On 2009-03-13, RoyJ wrote:
1) properly lubed sleeve bearing have a longer service life in certain
applications like furnace blowers. In the 'old' days, they were used in
the majority of motors since ball bearings had both shorter life and
were much more expensive.


What about modern balll bearings?
i


Jim Wilkins March 13th 09 04:19 PM

Electric motor shafts
 
On Mar 13, 10:03*am, "Wild_Bill" wrote:
...
On some older domestic USA motors, the manufacturer may have used cast end
end bells for the motor end plates that are very similar for both sleeve and
ball bearing models.
For the ball bearing models, they eliminate the extra material used for the
sleeve model, and machine a counterbore/pocket for the ball bearing
assembly.
This means that if a HSM discovers a good motor with worn sleeve bearings,
he can sometimes machine away the sleeve support webs in the end bell
castings to install ball bearings....
WB



Thanks, I'll watch for that.

Christopher Tidy March 13th 09 09:43 PM

Electric motor shafts
 
Michael Koblic wrote:

1) Are sleeve bearings usual in electric motors or is this some old, cheap
model?


Sleeve bearings are common in older motors. Like Roy said, a sleeve
bearing has some advantages over a rolling element bearing. They take
high loads better. They are also quieter as their stiffness doesn't vary
with position. Quite often sleeve bearings are more expensive than
rolling element bearings.

2) Are shafts in such motor usually machined in one piece or is a 3/4" shaft
rammed into a mandrel to hold the rotor? In spite copious cleaning I cannot
tell for sure.


Probably there is a shaft of 3/4" diameter (which is of a slightly
larger diameter in the centre; you are unlikely to be able to remove
this without turning down the shaft) which is somehow attached to the
rotor. The three methods I've seen for attachment a (i) small splines
on the shaft (the shaft is then pressed through an undersize hole in the
laminations), (ii) a key and keyway, and (iii) welding. Depending on the
method of attachment, you may be able to remove the rotor, but it
probably won't be easy. The rotor has to stay firmly and reliably
attached to the shaft in service.

3) I am puzzled at the inability to shift the rotor. If the sledge hammer
did not do the job is a gear puller (or some other gizmo) likely to succeed
(as well as protect the shaft, of course)?


Unless you have a very strong gear puller, probably not. A good strong
puller, like some of the larger Gedore/Baldur models, might be able to
move it. But a cheap gear puller won't.

4) Am I missing some method by which the rotor is held onto the shaft
rendering the sledge hammer ineffective?


It sounds like your rotor is secured by a key. If it's a taper key, this
is probably why you can't remove the rotor. Taper keys are designed to
jam tight. If it's a parallel key, there may be a threaded hole for a
grubscrew which holds the key in place. If so, you need to remove the
grubscrew. Rust may also be jamming the rotor in place.

If it's a taper key, I find the best way to remove them is using a
strong gear puller. You need a puller capable of exerting several tons
of force. Also, if you have to pull the rotor in the direction which
tends to push the taper key further in, put a piece of metal under the
head of the taper key to stop it sliding further in and jamming the
rotor on tighter.

Good luck!

Best wishes,

Chris


Newshound March 13th 09 10:07 PM

Electric motor shafts
 


"RoyJ" wrote in message
m...
Current ball bearings are made to better tolerances than older ones. The
ABEC numbers (higher is better) have stayed the same but a 30 year old
ABEC-3 is pretty close to a current ABEC-1. And even the import specials
are pretty good.

Ball bearings are good for higher speed and lower friction. Sleeve
bearings are good for lower speeds, higher average loads, but have
slightly higher friction (means heat in the bearing). A sleeve bearing
actually floats on a film of oil (assuming it's properly lubed) so there
is no metal to metal contact. Ball bearing have metal to metal contact
because the balls squeeze the lube out of the point of contact.


Actually no; when the design is right there is still a very thin oil film
there (although it is vulnerable to dirt in the lube). Google EHL

Everything is hardened but there is still the wear factor.

Sleeve bearings take severe impact loadings better. The relevant surface
area of a 3/4" shaft is around 1/2" wide. Compare that to the 3 or 4 ball
point contacts in a ball bearing. Of course a roller bearing has much more
contact area, they are used for the high impact applications.

I have some bearing balls out of a race car CV joint that show nasty
cratering under a 10x magnification. You can see rows of chips taken out
of the hardened surface, look almost like the gouge marks from a backhoe
tooth on a concrete road surface.

No again, the cratering will be pits produced by fatigue cracking, caused by
stress cycles. But as you say, the stress levels are very high

Ignoramus20387 wrote:
On 2009-03-13, RoyJ wrote:
1) properly lubed sleeve bearing have a longer service life in certain
applications like furnace blowers. In the 'old' days, they were used in
the majority of motors since ball bearings had both shorter life and
were much more expensive.

What about modern balll bearings?
i



Christopher Tidy March 13th 09 10:22 PM

Electric motor shafts
 
RoyJ wrote:

I have some bearing balls out of a race car CV joint that show nasty
cratering under a 10x magnification. You can see rows of chips taken out
of the hardened surface, look almost like the gouge marks from a backhoe
tooth on a concrete road surface.


Roy, if you want to sell one of those balls with the pitting, drop me a
line (chris AT ruggedmachines DOT com). I'm looking for an example of a
spalled surface that I can photograph under a microscope.

Best wishes,

Chris


RoyJ March 13th 09 11:45 PM

Electric motor shafts
 
Sent private response.

Christopher Tidy wrote:
RoyJ wrote:

I have some bearing balls out of a race car CV joint that show nasty
cratering under a 10x magnification. You can see rows of chips taken
out of the hardened surface, look almost like the gouge marks from a
backhoe tooth on a concrete road surface.


Roy, if you want to sell one of those balls with the pitting, drop me a
line (chris AT ruggedmachines DOT com). I'm looking for an example of a
spalled surface that I can photograph under a microscope.

Best wishes,

Chris


Christopher Tidy March 14th 09 12:17 AM

Electric motor shafts
 
RoyJ wrote:
Sent private response.


Thanks, Roy. It hasn't arrived in my inbox yet, but I'm sure it'll be
there tomorrow (unless you sent it to the address in the message header,
which is spam-trapped because of the insane amount of spam I was
getting?). I'll get back to you on it tomorrow.

Many thanks,

Chris


Michael Koblic March 14th 09 01:10 AM

Electric motor shafts
 
Christopher Tidy wrote:
Sleeve bearings are common in older motors.

big snip

Thanks, everyone!
I have learned more reading this thread than in three days of searching and
googling.

I think the end result with this item is scrap yard: the 3/4" section of the
shaft is too short for the coutershaft I had in mind. I could cut into the
rotor, remove it that way and then turn the rest of the shaft down to 3/4"
but for that ...I would need a lathe! I am sure the said scrap yard will
provide the necessary 3/4" shaft in some form :-)

The positive outcome of this may be that I shall feel more comfortable
designing the counterhaft with cheap sleeve bearings rather than expensive
pillow blocks.

Thanks again,

--
Michael Koblic,
Campbell River, BC



Jim Wilkins March 14th 09 01:11 PM

Electric motor shafts
 
On Mar 13, 9:10*pm, "Michael Koblic" wrote:

The positive outcome of this may be that I shall feel more comfortable
designing the counterhaft with cheap sleeve bearings rather than expensive
pillow blocks.
Michael Koblic,


The only real advantage of ball-bearing pillow blocks is that they can
swivel to align with the shaft, although as you've noticed some swivel
more freely than others. Sleeve bearings can be very hard to align if
you can't drill and ream them in one setup.


Michael Koblic March 15th 09 01:18 AM

Electric motor shafts
 
Jim Wilkins wrote:
On Mar 13, 9:10 pm, "Michael Koblic" wrote:

The positive outcome of this may be that I shall feel more
comfortable designing the counterhaft with cheap sleeve bearings
rather than expensive pillow blocks.
Michael Koblic,


The only real advantage of ball-bearing pillow blocks is that they can
swivel to align with the shaft, although as you've noticed some swivel
more freely than others. Sleeve bearings can be very hard to align if
you can't drill and ream them in one setup.


Copper water pipe out of the question then ? Worked before...I guess for
3/4" I should use something more sophisticated. I was thinking a couple of
bronze flanged bearings for $2 each in home-made pillow blocks. Not a good
idea?

--
Michael Koblic,
Campbell River, BC



Gerald Miller March 15th 09 06:19 AM

Electric motor shafts
 
On Sat, 14 Mar 2009 18:18:44 -0700, "Michael Koblic"
wrote:

Jim Wilkins wrote:
On Mar 13, 9:10 pm, "Michael Koblic" wrote:

The positive outcome of this may be that I shall feel more
comfortable designing the counterhaft with cheap sleeve bearings
rather than expensive pillow blocks.
Michael Koblic,


The only real advantage of ball-bearing pillow blocks is that they can
swivel to align with the shaft, although as you've noticed some swivel
more freely than others. Sleeve bearings can be very hard to align if
you can't drill and ream them in one setup.


Copper water pipe out of the question then ? Worked before...I guess for
3/4" I should use something more sophisticated. I was thinking a couple of
bronze flanged bearings for $2 each in home-made pillow blocks. Not a good
idea?

All depends on what you want to accomplish. The eccentrics on my
compost sifter run in fairly loose, well greased oak.
Gerry :-)}
London, Canada

Jim Wilkins March 15th 09 12:28 PM

Electric motor shafts
 
On Mar 14, 9:18*pm, "Michael Koblic" wrote:
Jim Wilkins wrote:
...Sleeve bearings can be very hard to align if
you can't drill and ream them in one setup.


Copper water pipe out of the question then ? Worked before...I guess for
3/4" I should use something more sophisticated. I was thinking a couple of
bronze flanged bearings for $2 each in home-made pillow blocks. Not a good
idea?

Michael Koblic,


There's quite a gap between the hack methods I've tried and the ones I
usually suggest in print. I started building working models when I was
a litle kid with only hand tools, scrap wood, nails, pipe and tin can
metal. My windmills and water wheels might run a month between major
overhauls.

Copper may last longer if you tin the inside, like crude Babbitt. I
tightened up the spindle bearing on my AA/Sears lathe with solder
which has been good enough for the little use it gets.

Jim Wilkins

Don Young March 16th 09 01:39 AM

Electric motor shafts
 

"Jim Wilkins" wrote in message
...
On Mar 14, 9:18 pm, "Michael Koblic" wrote:
Jim Wilkins wrote:
...Sleeve bearings can be very hard to align if
you can't drill and ream them in one setup.


Copper water pipe out of the question then ? Worked before...I guess for
3/4" I should use something more sophisticated. I was thinking a couple of
bronze flanged bearings for $2 each in home-made pillow blocks. Not a good
idea?

Michael Koblic,


There's quite a gap between the hack methods I've tried and the ones I
usually suggest in print. I started building working models when I was
a litle kid with only hand tools, scrap wood, nails, pipe and tin can
metal. My windmills and water wheels might run a month between major
overhauls.

Copper may last longer if you tin the inside, like crude Babbitt. I
tightened up the spindle bearing on my AA/Sears lathe with solder
which has been good enough for the little use it gets.

Jim Wilkins
I once repaired a worn evaporative cooler fan motor shaft with solder and a
file. It was still running good when I moved out of the house a year later.

Don Young




[email protected] March 16th 09 08:49 PM

Electric motor shafts
 
On Mar 13, 7:10*pm, "Michael Koblic" wrote:
Christopher Tidy wrote:
Sleeve bearings are common in older motors.


big snip

Thanks, everyone!
I have learned more reading this thread than in three days of searching and
googling.

I think the end result with this item is scrap yard: the 3/4" section of the
shaft is too short for the coutershaft I had in mind. I could cut into the
rotor, remove it that way and then turn the rest of the shaft down to 3/4"
but for that ...I would need a lathe! I am sure the said scrap yard will
provide the necessary 3/4" shaft in some form :-)

The positive outcome of this may be that I shall feel more comfortable
designing the counterhaft with cheap sleeve bearings rather than expensive
pillow blocks.

Thanks again,

--
Michael Koblic,
Campbell River, BC


Just depends on the load and the speed. Remember, there once was no
such thing as a ball bearing. All those overhead shafts and the tools
that they drove had sleeve bearings. And they weren't necessarily
metal, either. One of the small businesses near where I used to live
when I was a kid made wood bearings, they used to be used in old
washing machines. Propeller shaft stuffing boxes for boarts used to
be lignum vitae, too. Just depends on load, load type and speed.
Keep the sleeve bearings well oiled and they last for a long time. If
you really want to get old-timey, look up "ring oiler".

Stan

Jim Wilkins March 16th 09 08:54 PM

Electric motor shafts
 
On Mar 16, 4:49*pm, wrote:
...
Keep the sleeve bearings well oiled and they last for a long time. *If
you really want to get old-timey, look up "ring oiler".

Stan-


My surface grinder has one of those on the wheel end of the spindle,
the other has a ball bearing. The grinder was designed in 1942,
patented in '45.


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