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Old Delta/Rockwell bandsaw - bearing lubrication?
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Jules Richardson
Oct 11, 2013, 7:29:41 PM10/11/13
to
I picked up an old Delta/Rockwell 10" bandsaw a while ago (model 28-113)
for peanuts - I don't think this model was ever considered particularly
good (it's got the plastic wheels), but it'd be OK for the kind of stuff
I'd use it for.
Anyway, the bronze driveshaft bearings were completely shot - but when I
pulled them out so I could replace them, I found that the one on the
drive pulley side completely blocks the grease fitting pathway!
It seems impossible that it was always like that; there's a cavity within
the saw's cast frame which still had some grease in it (albeit not much).
So I assume that the bearings have been replaced at some point in the
saw's life; did the original (on the grease fitting side) maybe have a
notch to allow grease in? Or perhaps a hole, and grease could flow
between the bearing and driveshaft into the cavity (but this seems
unlikely as the clearance between bearing and driveshaft is so small)?
Another possibility is that according to the parts break-down (e.g.
http://www.toolpartsdirect.com/cgi-bin/schematic.cgi/rockwell/28-113),
replacement bearings were supplied over-size and the frame would have to
be reamed to get them to fit - in which case was there perhaps originally
a channel in the frame between the grease fitting and internal cavity,
and reaming took this out (and whoever did the work didn't cut a new one)?
The bearings which were fitted were 10/16" ID and 13/16" OD (and 12/16"
OD seems much easier to obtain, again perhaps suggesting that the saw has
over-size replacements), and I've got some new ones to put in - but in
order to fix the lube problem properly it would be useful to know what
the original setup would have been.
cheers
Jules
Nick
Oct 14, 2013, 8:35:59 PM10/14/13
to
"Jules Richardson" <julesrichar...@gmail.com> wrote in message
news:l3a1l4$l9i$1...@dont-email.me...
#64. To be of any use 63 would have both an external groove and a bore to
allow oil or grease to pass into the bearing. This groove to align with the
hole into which the oiler fits. Internally the bearing would probably (damn,
late at night, lost worms) have a spiral channel to distribute lubricant to
the shaft.
You say above 'driveshaft bearings' but the drawing shows only one bearing.
I wonder if at some time in the past the original bearing has been replaced
by two sleeves; which could allow a space in between for lubricant dispersal
but in this instance has been poorly manufactured/fitted? Too long a
sentence but I hope you'll get my drift. Looking at the drawing, the oiler
seems to be set at an angle. I reckon someone has fitted new sleeves to this
at some some and has blocked the oiler pathway.
Could the frame be modified to take sealed bearings?
Just my 2d's
dpb
Oct 14, 2013, 9:08:14 PM10/14/13
to
On 10/11/2013 6:29 PM, Jules Richardson wrote:
...
>
> Anyway, the bronze driveshaft bearings were completely shot - but when I
> pulled them out so I could replace them, I found that the one on the
> drive pulley side completely blocks the grease fitting pathway!
>
> It seems impossible that it was always like that; there's a cavity within
> the saw's cast frame which still had some grease in it (albeit not much).
> So I assume that the bearings have been replaced at some point in the
> saw's life; did the original (on the grease fitting side) maybe have a
> notch to allow grease in? Or perhaps a hole, and grease could flow
> between the bearing and driveshaft into the cavity (but this seems
> unlikely as the clearance between bearing and driveshaft is so small)?
...
I think it's the latter; that you're supposed to drill the hole before
installation. The point of the cap on the "oiler" if it's as the one
I've seen that's a set screw is that you put some grease in there and
then the screw forces it down into the area and then the shaft rotation
carries some into the annular space. One should, of course, coat the
interior fully before inserting the shaft.
That's if the bushing is solid bronze; alternatively, if the bushings
supplied are sintered they use oil instead of grease and it's supposed
to work it's way thru the pores.
Unfortunately, as the other poster suggests there likely isn't
sufficient material to support any sealed bearing which would be the
cat's meow if so...
--
...
>
> Anyway, the bronze driveshaft bearings were completely shot - but when I
> pulled them out so I could replace them, I found that the one on the
> drive pulley side completely blocks the grease fitting pathway!
>
> It seems impossible that it was always like that; there's a cavity within
> the saw's cast frame which still had some grease in it (albeit not much).
> So I assume that the bearings have been replaced at some point in the
> saw's life; did the original (on the grease fitting side) maybe have a
> notch to allow grease in? Or perhaps a hole, and grease could flow
> between the bearing and driveshaft into the cavity (but this seems
> unlikely as the clearance between bearing and driveshaft is so small)?
I think it's the latter; that you're supposed to drill the hole before
installation. The point of the cap on the "oiler" if it's as the one
I've seen that's a set screw is that you put some grease in there and
then the screw forces it down into the area and then the shaft rotation
carries some into the annular space. One should, of course, coat the
interior fully before inserting the shaft.
That's if the bushing is solid bronze; alternatively, if the bushings
supplied are sintered they use oil instead of grease and it's supposed
to work it's way thru the pores.
Unfortunately, as the other poster suggests there likely isn't
sufficient material to support any sealed bearing which would be the
cat's meow if so...
--
Jules Richardson
Oct 15, 2013, 10:23:34 AM10/15/13
to
On Mon, 14 Oct 2013 20:08:14 -0500, dpb wrote:
> On 10/11/2013 6:29 PM, Jules Richardson wrote:
> ...
>
>
>> Anyway, the bronze driveshaft bearings were completely shot - but when
>> I pulled them out so I could replace them, I found that the one on the
>> drive pulley side completely blocks the grease fitting pathway!
>>
>> It seems impossible that it was always like that; there's a cavity
>> within the saw's cast frame which still had some grease in it (albeit
>> not much).
>> So I assume that the bearings have been replaced at some point in the
>> saw's life; did the original (on the grease fitting side) maybe have a
>> notch to allow grease in? Or perhaps a hole, and grease could flow
>> between the bearing and driveshaft into the cavity (but this seems
>> unlikely as the clearance between bearing and driveshaft is so small)?
> ...
>
> I think it's the latter; that you're supposed to drill the hole before
> installation. The point of the cap on the "oiler" if it's as the one
> I've seen that's a set screw is that you put some grease in there and
> then the screw forces it down into the area and then the shaft rotation
> carries some into the annular space. One should, of course, coat the
> interior fully before inserting the shaft.
>
> That's if the bushing is solid bronze; alternatively, if the bushings
> supplied are sintered they use oil instead of grease and it's supposed
> to work it's way thru the pores.
These are oil-impregnated bronze, but I don't think that they're porous -
> On 10/11/2013 6:29 PM, Jules Richardson wrote:
> ...
>
>
>> Anyway, the bronze driveshaft bearings were completely shot - but when
>> I pulled them out so I could replace them, I found that the one on the
>> drive pulley side completely blocks the grease fitting pathway!
>>
>> It seems impossible that it was always like that; there's a cavity
>> within the saw's cast frame which still had some grease in it (albeit
>> not much).
>> So I assume that the bearings have been replaced at some point in the
>> saw's life; did the original (on the grease fitting side) maybe have a
>> notch to allow grease in? Or perhaps a hole, and grease could flow
>> between the bearing and driveshaft into the cavity (but this seems
>> unlikely as the clearance between bearing and driveshaft is so small)?
> ...
>
> I think it's the latter; that you're supposed to drill the hole before
> installation. The point of the cap on the "oiler" if it's as the one
> I've seen that's a set screw is that you put some grease in there and
> then the screw forces it down into the area and then the shaft rotation
> carries some into the annular space. One should, of course, coat the
> interior fully before inserting the shaft.
>
> That's if the bushing is solid bronze; alternatively, if the bushings
> supplied are sintered they use oil instead of grease and it's supposed
> to work it's way thru the pores.
the oil just helps them to last longer, but they still need greasing.
Searching for the original p/n (920-75-011-2796) turns up a couple of
images, both of which appear to be plain bearings/bushings - no holes,
grooves etc.
I don't understand how grease is supposed to get to where it's needed,
but I have seen this setup - a grease chamber and plain bearings at the
ends of a plain shaft - before; e.g. the right-angle drive on my tiller
and the back axles on my pair of lawn tractors are like that. It just
seems a bit wasteful as what's the point of having a big chamber full of
grease when only a little bit of it is doing useful work (it's different
for the tractors and tiller as the gears sit in the grease)? Maybe as the
bearings get warm they're supposed to "wick" more grease from the chamber
or something.
Anyway, what I've done for now is cut a small ("internal") slot in the
saw's frame between the grease point and the interior grease chamber;
that will allow me to pump grease into the chamber with the bearings
fitted (from where it will be forced between the bearings and shaft,
although I'll still pre-grease everything before assembly, of course). It
would just be nice to find someone who has taken one of these saws "in
original condition" apart just to see what the setup is!
Maybe it was just supposed to be routine maintenance every x months to
force more grease into the chamber via the grease point, and this in turn
would force fresh grease into the bearings. Of course, hardly anyone
likely did so...
> Unfortunately, as the other poster suggests there likely isn't
> sufficient material to support any sealed bearing which would be the
> cat's meow if so...
is just too big. It could probably be done using a bearing carrier
mounted to the frame (although there's not much clearance on the pulley
side), but realistically I only got this saw for light use (I've got $15
in it right now*, including the new bearings) and if that changed I'd be
better spending a few hundred on a decent saw rather than putting $50
into a saw that would still be left with cheap plastic wheels :-)
* add $10 for a 1/2HP motor, but I want to make sure it all runs true
before getting that far.
cheers
Jules
Jules Richardson
Oct 15, 2013, 10:42:36 AM10/15/13
to
On Tue, 15 Oct 2013 01:35:59 +0100, Nick wrote:
> From what I can see the bearing #63 is fed with lubricant from the oiler
> #64. To be of any use 63 would have both an external groove and a bore
> to allow oil or grease to pass into the bearing. This groove to align
> with the hole into which the oiler fits. Internally the bearing would
> probably (damn,
> late at night, lost worms) have a spiral channel to distribute lubricant
> to the shaft.
> You say above 'driveshaft bearings' but the drawing shows only one
> bearing. I wonder if at some time in the past the original bearing has
> been replaced by two sleeves; which could allow a space in between for
> lubricant dispersal but in this instance has been poorly
> manufactured/fitted? Too long a sentence but I hope you'll get my drift.
Hmm, there would have to be *something* supporting the shaft at the wheel
> From what I can see the bearing #63 is fed with lubricant from the oiler
> #64. To be of any use 63 would have both an external groove and a bore
> to allow oil or grease to pass into the bearing. This groove to align
> with the hole into which the oiler fits. Internally the bearing would
> probably (damn,
> late at night, lost worms) have a spiral channel to distribute lubricant
> to the shaft.
> You say above 'driveshaft bearings' but the drawing shows only one
> bearing. I wonder if at some time in the past the original bearing has
> been replaced by two sleeves; which could allow a space in between for
> lubricant dispersal but in this instance has been poorly
> manufactured/fitted? Too long a sentence but I hope you'll get my drift.
end, though; the shaft runs around 3" through the frame, so a single
bearing at the opposite end to the wheel (which is under stress from
blade tension) wouldn't last long. I did find a couple of diagrams for
other Rockwell/Delta saws of the same era, which seem to show the same
shaft, and use two bearings (both with the same p/n as the one listed for
my saw). I think they just managed to miss it off the diagram for the saw
that I have.
> Looking at the drawing, the oiler seems to be set at an angle. I reckon
> someone has fitted new sleeves to this at some some and has blocked the
> oiler pathway.
replacements are supplied over-size and the frame has to be reamed for
them to fit; I expect someone just didn't take into account the need to
also cut a new path for the lube.
Whether there were internal spiral grooves or anything on the originals,
I don't know - although the couple of photos of the same part that I've
found online don't seem to show any (and it seems unlikely that Delta/
Rockwell would expect someone to machine those themselves - although I
suppose they did expect them to ream out the frame!). For now, I've cut a
channel between the grease fitting and the internal chamber, and I'll see
how that goes (it won't be much work to dismantle and check for wear
after x hours of use)
> Could the frame be modified to take sealed bearings?
although external bearings with a carrier might be technically possible
(but just not worth the effort in a saw of this class).
cheers
Jules
WW
Oct 15, 2013, 11:27:56 AM10/15/13
to
"Jules Richardson" wrote in message news:l3a1l4$l9i$1...@dont-email.me...
I call roller bearings??? WW
Jules Richardson
Oct 15, 2013, 12:04:43 PM10/15/13
to
On Tue, 15 Oct 2013 09:27:56 -0600, WW wrote:
> After reading the other replies......How about needle bearings that is
> what I call roller bearings??? WW
Yes, I think they're the same thing. They should be narrower than ball
> After reading the other replies......How about needle bearings that is
> what I call roller bearings??? WW
bearings, but I did notice on one Delta saw that they fitted a needle
bearing for the top wheel only on earlier ones, but then changed it to a
sleeve on later ones, so I wonder if they had problems with the needle
bearing not taking the load (or maybe it was prone to sawdust getting in
and then wearing out quickly... or maybe they were just trying to cut
costs :-)
J.
dpb
Oct 15, 2013, 12:43:54 PM10/15/13
to
On 10/15/2013 10:27 AM, WW wrote:
...
> After reading the other replies......How about needle bearings that is
> what I call roller bearings??? WW
needle bearing isn't the same as a roller bearing, no...both are rollers
as opposed to a ball, yes, but much different...but a good idea and can
even actually find something that might just work...
<http://www.amazon.com/INA-SCE1010-17600rpm-Rotational-Capacity/dp/B0026GTP7U>
--
...
> After reading the other replies......How about needle bearings that is
> what I call roller bearings??? WW
as opposed to a ball, yes, but much different...but a good idea and can
even actually find something that might just work...
<http://www.amazon.com/INA-SCE1010-17600rpm-Rotational-Capacity/dp/B0026GTP7U>
--
Jules Richardson
Oct 16, 2013, 7:43:15 PM10/16/13
to
On Tue, 15 Oct 2013 11:43:54 -0500, dpb wrote:
> On 10/15/2013 10:27 AM, WW wrote:
> ...
>
>> After reading the other replies......How about needle bearings that is
>> what I call roller bearings??? WW
>
> needle bearing isn't the same as a roller bearing, no...both are rollers
> as opposed to a ball, yes, but much different...
Hmm, I'd always thought that they were basically the same thing.
> On 10/15/2013 10:27 AM, WW wrote:
> ...
>
>> After reading the other replies......How about needle bearings that is
>> what I call roller bearings??? WW
>
> needle bearing isn't the same as a roller bearing, no...both are rollers
> as opposed to a ball, yes, but much different...
http://en.wikipedia.org/wiki/Rolling-element_bearing#Roller_bearings
... seems to say that a needle bearing is a sub-class of roller bearing
(so it's perhaps fair to call a needle bearing a roller bearing, but not
necessarily the other way around :-)
> <http://www.amazon.com/INA-SCE1010-17600rpm-Rotational-Capacity/dp/
B0026GTP7U>
I think that picture's wrong, and shows a plain sleeve bearing - googling
the same part-number turns up other sites selling the same part, but with
pictures of a bearing that obviously has rollers. Weird.
cheers
Jules
Lew Hodgett
Oct 16, 2013, 8:23:06 PM10/16/13
to
WW wrote:
>> ...
>>
>>> After reading the other replies......How about needle bearings
>>> that is
>>> what I call roller bearings??? WW
dpb wrote:
>>
>> needle bearing isn't the same as a roller bearing, no...both are
>> rollers
>> as opposed to a ball, yes, but much different...
-----------------------------------------------------------------------
>>
>> needle bearing isn't the same as a roller bearing, no...both are
>> rollers
>> as opposed to a ball, yes, but much different...
"Jules Richardson" wrote:
>
> Hmm, I'd always thought that they were basically the same thing.
>
> http://en.wikipedia.org/wiki/Rolling-element_bearing#Roller_bearings
----------------------------------------------------------------
>
> Hmm, I'd always thought that they were basically the same thing.
>
> http://en.wikipedia.org/wiki/Rolling-element_bearing#Roller_bearings
Needle bearings and roller bearings are totally different animals.
It's been a long time since I was involved in bearing application
design,
but for openers there is at least a 10:1 price difference and most
needle
bearings I'm familiar with do not have an inner race, they use the
shaft.
Lew
dpb
Oct 16, 2013, 8:33:56 PM10/16/13
to
They're both based on rollers rather than balls, yes, so I'll concede
the point... :)
But, I think of them as substantially different owing to the
dissimilarities in structure so generally don't call one the other meself...
Anyway, on looking at the picture I agree they've got the wrong picture;
I assume the product is probably as described. I though at first glance
it was enclosed/sealed which would be ideal for the purpose but think on
further and more close looking it is the bushing, too.
Another link I found has several of what look to be right I/OD of
various loading ratings...probably no different than what you've found
but I'll post the link anyway...
<http://www.globalindustrial.com/c/motors/bearings/needle-roller-bearings?p=category%3D8Q1U%2Cattr+borefwmminch%28text%29%3D15.875+\%285\%2F8\%29>
--
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