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General Forestry => Sawmills and Milling => Topic started by: millstead on January 31, 2013, 08:07:13 AM

Title: hot bearings
Post by: millstead on January 31, 2013, 08:07:13 AM
i replaced the drive bearings on my lt30. the old bearings went out so i called woodmizer and they sold me 2 new pillow block bearings and a new shaft the bearings where allready pressed on the shaft all i had to do was bolt iton the machine. after running the machine for 20-30 minutes the bearings where hot and grease was dripping out of the bearings. i checked the allignment and everything checked out ok and the shaft spins free with no binding so i tried again this time without a blade and checked to make sure the drive belts where not to tight and the samething happened. the bearing where not so hot that you could not touch them but they where still pretty hot. i called woodmizer to see if they had any advice and they told me not to worry about it that the bearing will run hot for 100-200 hours untill they break in and the reason the grease was running out was there was to much grease in the bearing  as long as the grease was not steaming that it was ok. i trust what woodmizer says they know more than i do but i have never heard of a bearing having to break in. if anyone else has had similar problems i would like to hear other opinions thanks
Title: Re: hot bearings
Post by: SPD748 on January 31, 2013, 10:45:05 AM
New bearings will often times run hot, even too hot to touch the housing. The Woodmizer tech was correct, give them some hours to break in to the races. There isn't usually a problem until the grease is steaming, as stated.

Title: Re: hot bearings
Post by: wildbill on January 31, 2013, 12:12:30 PM
Yes some bearings have a break in period.  I had lift pump bearings run 60F hotter for 2 months before they came down.

We lubricate bearings by temperature not time and it makes them last a lot longer. (But we also use ultrasound to listen to when the right amount is in there also)

Bearing alignment is one of my jobs where i work but i use lasers to align shafts to. 002"
Title: Re: hot bearings
Post by: wildbill on January 31, 2013, 12:21:49 PM
Oh and if your bearing temps are under 190F you should be fine.  Most all greases can handle that with little to no break down.

Keep an eye on the  where the grease leaked out.  Technically those seals are no good any longer.  But will probably be fine for your application
Title: Re: hot bearings
Post by: SPIKER on January 31, 2013, 06:15:54 PM
Hey Bill:  Is that a pic of your PET looks like the South End of a North Bound Skunk  smiley_airfreshener smiley_eek_dropjaw smiley_smelly_skunk

great advice on the Bearings too BTW  lol
Title: Re: hot bearings
Post by: wildbill on January 31, 2013, 08:34:16 PM
yep, thats one of our yard birds.  her name is sha-she-qua.  meanest hen on the planet but cannot see past her "fro" so she doesnt aquire a target frequently. 

if leaking seals becomes a problem you can switch to a slightly heavier grease to keep it in the bearings.

remember over greasing is the most common cause of bearing failure
Title: Re: hot bearings
Post by: Old Iron nut on January 31, 2013, 10:45:01 PM
   If that heating leads to bearing failure you may have to go to a fixed bearing on the end of the shaft that you do not want to move and an expansion bearing on the opposite end of the shaft. This will eliminate the heating problem and the bearing failure. Dodge makes these bearings and they are not cheap. I have them on my mill. Cheers, Old Iron nut.
Title: Re: hot bearings
Post by: millstead on February 01, 2013, 08:38:52 AM
I'm glad to here that its ok for the bearings to get hot  I have not used my mill in awhile because of it yesterday was the first I used the mill in a couple  months felt good to saw some logs again I sawed some cherry logs and the milled sawed great I put a new engine on when I changed the bearings I swaped the 11hp Tecumseh for a 23hp vanguard  I really could not be happier with the way it saws now it is so fast and doesn't bog down at all. Thanks for all the help with the bearings
Title: Re: hot bearings
Post by: hardtailjohn on February 01, 2013, 10:15:06 AM
On our rock crusher, the cross shaft  (4" diameter shaft, with tapered roller bearings on it) bearings were getting warm one day and spewing some grease... my wife runs the crusher and does the maintenance, so I figured it was over greasing. When I quizzed her about it, she'd used #2 grease on them.... the mfg calls for #1. So we switched back to #1 and temps went down and cleaned right up. Maybe something to think about? That shaft is loaded heavy with 5 "D" section belts 20' away from the power source on one end and 6 "C" section on the other. It's only lasted since 1950, so I'd say it's doing ok on #1 grease.....
Title: Re: hot bearings
Post by: thecfarm on February 01, 2013, 10:29:02 AM
A rock crusher? Pictures? I could use one of them. But I would have to make the 4 footers small first,I suppose.  :D  I think they was using one on the gravel pit about a mile from here. That critter was making some noise and I don't mean engine noise either. Only lasted a few weeks.