Greasing motor bearings

With all the talk of excess grease hurting motor bearings, I have been reluctant to add grease to a motor that probably could use some. The
motor for my lathe has screws where the grease fitting would go , but I haven't greased it in the 30 years I've had it. I probably ought to do that. What grease and how much?
RWL
Add pictures here
✖
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
are you sure that putting grease in the screw holes will reach the bearings? Do you have a lathe manual you could check? sometimes the same castings support ball bearings and busings, and the holes are covered over for ball bearings - sometimes they are there so you can install a grease fitting and grease - your manual may well provide useful guidance
<GeoLane at PTD dot NET> wrote in message

Add pictures here
✖
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Wed, 31 Mar 2010 20:28:29 -0700, "Bill Noble"

This was a motor I added after I got the lathe, so it's not referenced in the owner's manual. The original motor was 3 phase, and 30 years the ease of making a rotary phase converter was a big secret, so I just replaced it with a single phase motor.
RWL
Add pictures here
✖
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Mar 31, 7:39 pm, GeoLane at PTD dot NET <GeoLane at PTD dot NET> wrote:

Are you sure it's a ball-bearing motor? Bushings take oil, not grease. And are you sure it's got open ball-bearings if it IS ball- bearing? If they're double-shielded numbers, there's no entrance for grease. As far as what to use, auto wheel-bearing grease will work. If it has bleed holes for excess grease, pump it in until you get the old stuff out. What you want to do is get the old soap carrier out and replace it with the new stuff. If you start pumping, though, and there's no internal grease seal, you could get grease inside, which wouldn't help with running.
Safest way would be to disassemble the motor, manually pack the bearings and reassemble. You could vacuum out the crap that accumulates that way, too. Or if you've got it down that far, replace the bearings.
Stan
Add pictures here
✖
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I agree with Stan 100%. Swapping bearings on a motor is easy and usually inexpensive. You can get great quality permalube bearings that will essentially never need any attention, at least in HSM setting.
i
Add pictures here
✖
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thu, 01 Apr 2010 15:50:21 -0500, Ignoramus23298

OK. Do nothing it is. They aren't making any noise now and if bearings are cheap, it would just be easier to replace them than the hassle of pulling the motor now for preventive maintenance. I plan to sell this machine when I have the rebuild of the varispeed drive completed on my new Clausing.
RWL
Add pictures here
✖
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thu, 01 Apr 2010 21:36:16 -0400, GeoLane at PTD dot NET <GeoLane at PTD dot NET> wrote:

If the motor was designed to be periodically greased it will have a threaded hole, usually plugged, both top and bottom of the bearing housing. To lube one you removed both the top and the bottom plug; screwed a grease fitting in the top hole and pumped grease into the bearing until clean grease came out the bottom. Removed the grease fitting and reinstalled both plugs.
It was in every makers instructions and particularly the warning to remove the bottom plug and NOT pressurize the bearing housing and force grease through the seal and into the body of the motor.
Cheers,
John D. (jdslocombatgmail)
Add pictures here
✖
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.