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General Forestry => Sawmills and Milling => Topic started by: woodrat on January 15, 2009, 02:44:28 PM

Title: main drive bearing question
Post by: woodrat on January 15, 2009, 02:44:28 PM
So I finally broke down and coughed up the $300 plus dollars to purchase a new main drive bearing. Mine has been rumbling for a while and I couldn't put it off any longer. I'm almost done installing it, after some requisite cursing and finger smashing.

My question is whether or not the old bearing can be rebuilt, so I have a spare on hand for next time?
Title: Re: main drive bearing question
Post by: york on January 15, 2009, 03:34:39 PM
Hi,
what is this bearing on?How long did the old bearing last?

Bert
Title: Re: main drive bearing question
Post by: WH_Conley on January 15, 2009, 04:44:42 PM
I have one off a Wood-mizer laying dow at the mill, been wondering ths same thing. Not supposed to be re-buildable. Somebody built it to start with.
Title: Re: main drive bearing question
Post by: woodrat on January 15, 2009, 06:01:38 PM
oh, right. It's a 96 woodmizer.

The guys at WM portland said they didn't think it could be rebuilt, but it seems unlikely that that would be true. it does look like it would have to be pressed apart.

Title: Re: main drive bearing question
Post by: Don_Papenburg on January 15, 2009, 06:58:28 PM
Heck you ain't out nuthin ,Do exploritory on that thing  . If you can't repair it then save your pennies.
Title: Re: main drive bearing question
Post by: cheyenne on January 15, 2009, 08:04:50 PM
Bearings can not be rebuilt because of the wear factor, heat treating process & grinding......Cheyenne
Title: Re: main drive bearing question
Post by: WH_Conley on January 15, 2009, 08:28:52 PM
Got tear that thing apart, looks like it would be two bearings on a shaft. Don't beleive it would be re-building a bearing. More like replacing bearings.
Title: Re: main drive bearing question
Post by: pineywoods on January 15, 2009, 11:09:55 PM
Heck, I didn't know you couldn't rebuild that main drive shaft. I've done it twice, on the same mill. Got new bearings from a local bearing supply. You really need a hydraulic press, but otherwise it ain't nearly as hairy as rear wheel bearings on a pickup truck. The only hard part is re-aligning the rascal when you put it back on the mill.
Title: Re: main drive bearing question
Post by: backwoods sawyer on January 16, 2009, 12:13:46 AM
I have rebuilt the up down gearbox the same way. The local bearing shop takes measurements, orders in the parts, I take it and all the new parts to a shop that has a press, now for a $75.00 investment, I have a spare gearbox on the shelf. Will I ever need it on the mill? I hope not.
Title: Re: main drive bearing question
Post by: bandmiller2 on January 16, 2009, 08:27:45 AM
Woodmizer is saving themselves alot of problems by selling the assembly only.The average guy does not have the propper tool and knowledge to rebuild press fit assemblies,he would heat and beat and the results would not run true.Outher than castings most mill stuff is off the shelf  or welded up assemblies , repairable or can be duplicated.A friend sell tractor parts he won't sell water pump repair kits nothing but trouble.Frank C.
Title: Re: main drive bearing question
Post by: sparks on January 16, 2009, 10:02:25 AM
The problem with rebuilding them is we make the parts and then we assemble them by pressing the bearing on at the same time so that it is preloaded correctly. The issue is on disassembly. Trying to push the shaft out of one of the bearings without damaging the case. I have heard of a few successful rebuilds but I have also heard it failed within 100 hrs after the rebuild. Good luck.   
Title: Re: main drive bearing question
Post by: pineywoods on January 16, 2009, 10:19:15 AM
I concur with spark's comments. After replacing the bearings twice, I fully understand why WM would prefer to sell the complete assembly. You definitely need a big press. Heat and hammer is not a good idea. I did it twice on the same mill, second time because the owner (not me) ran the bearings dry. This was on an older mill that did not have the oil level sight tube.. Also, keep in mind that I'm one of those guys who is too dumb to know I can't do that, so I just went ahead and did it. :)
Title: Re: main drive bearing question
Post by: backwoods sawyer on January 16, 2009, 10:20:14 PM
A can under stand why woodmizer would rather send out a complete unit rather then a rebuild kit, then a complete unit a week later.
My background is in the big mills where we design, build and install our own gearboxes so I under stand what makes them tick and how to take them apart and reassemble them. It is not something your average car mechanic has experience with. By the same token, my background has also been heavy into diesel mechanic rather then autos, so I do not mess with rebuilding carburetors. If it is with in your comfort zone to rebuild it then that is an option.