Decided to post this under sawmills as this is from the bearing on my mill's band wheels.
I recently needed to change out the belts on my mill (B56 are the manufacturer spec'ed belts)
Manufacture procedures are to remove the wheels and replace the belts on the bench. A lot of owners do the replacement on the mill. I try to change the belts on the mill and if I succeed fine but if not then pull the wheel and go to the bench. In this case the belt rolled more than normal and I was unable to straighten it out on the mill and thus went to "plan B" the bench.
As I pulled the idle wheel the inner part of the bearing stayed on the shaft of the mill.
Bearing part nomenclature is not always clear to me. :)
Whether it is the inner ring or the inner race of the bearing (which is a pressed bearing) this one has a split inner race. It came out of the bearing body as I slid the wheel off the shaft.
In the picture you can see the split retaining ring in the recess (end of red line)
(https://forestryforum.com/gallery/albums/userpics/20691/Bearing_1.jpg?easyrotate_cache=1495223845)
At the end of the red line is the recess that snaps onto the split retaining ring.
(https://forestryforum.com/gallery/albums/userpics/20691/bearing_2.jpg?easyrotate_cache=1495223845)
It did not appear that anything fell out of the bearing so I snapped/pressed the split race back into the bearing.
My question is: not being a bearing expert by any stretch does this happen frequently when you slide a bearing off a shaft? I have never had this happen before.
Any concerns/thought you have - would be appreciated.
What mill do you have?
The one on my Woodmizer is 1 piece.
PC
I suspect that your bearing is an angular contact bearing type (read expensive). They do come apart with a little pressure. If it is, they have a pre-load specification. In other words the nut needs to be not to tight, not to loose. You might give a call to the mill manufacture to check for sure.
Regular bearings are a deep groove type and don't come apart.
Yes, angular contact bearing, very much like the bearings on a trailer. You have to set pre-load with the correct amount of pressure.....not too loose, and not too tight, or you will destroy the shaft in use.
A call to your manufacturer should solve it. Feigning that, I typically will set preload so that the bearing is tight enough to spin under very light pressure with no looseness or wobble. Very hard to describe correctly without showing in person.
Thanks for the response.
Manufacturer says to torque to 140 Ft lbs. I did that hope that is all that is needed.
Not sure what you are referring to as preload in this instance so I went on line and did a search.
Came away even more confused as the way you preload a wheel bearing on a car is the only thing I know of and the only thing I found so ......
In the case of a bandsaw drive wheel/idler wheel how do you preload it?
Do you set it to one torque run it then set the final torque?
Same thing. Use the manufacturers specs.
I thought that when you preload a bearing you tighten it up and then back it off and then torque it to a spec...but what do I know I'm not a doctor, I just play one in a movie
Quote from: 4x4American on May 21, 2017, 12:57:12 PM
I thought that when you preload a bearing you tighten it up and then back it off and then torque it to a spec...but what do I know I'm not a doctor, I just play one in a movie
Kind of what I thought until I did an internet search on the topic and then I got really confused as I read everything from soup to nuts on what preload is and how to do it.
I know nothing except that if you torque a bearing race to 140 lbs, it ain't gonna last long. :o
Quote from: Magicman on May 21, 2017, 03:41:51 PM
I know nothing except that if you torque a bearing race to 140 lbs, it ain't gonna last long. :o
I was thinking the same thing... If I don't know the torque I tighten it up and turn the bearing. After you do it long enough you get a fell for it. Running it to loose is better
than to tight.
A lot of speculation going on, none of us know how this bearing is set up. Steve
Quote from: ladylake on May 21, 2017, 03:58:47 PM
A lot of speculation going on, none of us know how this bearing is set up. Steve
Have to agree with Steve on this. We don't know how the bearing is set up.
I am not that knowledgeable on bearings either and I learned from Larry the term "angular contact bearing" which I had never heard before.
However to say as was posted "I know nothing except that if you torque a bearing race to 140 lbs, it ain't gonna last long" while maybe true, makes an assumption that may not be accurate either.
There is a lot of information missing and the OP seems to be missing information as well and that is what they were asking/searching for.
They asked: "My question is: not being a bearing expert by any stretch does this happen frequently when you slide a bearing off a shaft? "
Unfortunately I am not able to help the OP on that question as I have no idea as to how to answer that and it appears that no one else does either.
On the issue of the 140 ft lbs torque. I have a TK mill so it rang a bell.
The 140 ft lbs torque makes me think the OP may have a Timberking mill as TK in the belt changing video at about 8:50 into it, specifies 140 ft lbs torque on the re installation of the wheel so the manufacture (if the OP has a TK) does specify 140 ft lbs on the bearing torque.
Just saying.
I was unable to insert a link to the belt changing video for some reason this morning so that it displayed correctly. Thus no direct link.
I see that everyone is agreeing that since there are unknowns, caution is advised. Know exactly what the manufacturer's specifications are before proceeding.
If these bearings are set up with a spacer between the inner races 140# of torque would be just fine, no spacers then finger tight. Steve
Generally, a setting ranging from near zero to slight preload maximizes bearing life. Some applications use moderate preload to increase rigidity of highly stressed parts that would otherwise be adversely affected by excessive deflection and misalignment. Excessive preload, though, can drastically reduce bearing fatigue life or cause high temperatures that can quickly lead to bearing damage.