Help with Saw Bearings

[Jerry Bruette]

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Here's three pictures of sheave misalignment and how to check them with a straight edge or a string. I always used a string at work, it was easier to carry in my pocket. I don't think you'll have t worry too much about the angular misalignment, parallel might be off but sheave groove would be the most likely culprit. Sorry for the rotation.

For your bearing replacement, you'll have to pull or press the bearings off and you can drive the new bearings on. If you drive the bearings onto a shaft make sure to drive on the inner ring only and if you drive them into a housing make sure to drive on the outer ring only. The bearing size Ron referred to has shields, the zz suffix means shields. A skf bearing would be 6203-2rs the 2rs means a rubber seal on each side of the bearing. Either one will work but the sealed one will keep more crud out.

[Ronald Blue]

For your bearing replacement, you'll have to pull or press the bearings off and you can drive the new bearings on. If you drive the bearings onto a shaft make sure to drive on the inner ring only and if you drive them into a housing make sure to drive on the outer ring only. The bearing size Ron referred to has shields, the zz suffix means shields. A skf bearing would be 6203-2rs the 2rs means a rubber seal on each side of the bearing. Either one will work but the sealed one will keep more crud out.

The original apparently is shielded. That number came right off their parts list. A very common bearing and easily sourced though whichever he chooses. I agree the sealed might be the better choice.

[Bill Dufour]

I like to take the old bearings and grind the outer diameter down a tiny amount. Then take them apart and anneal the inner race and drill it out a fraction. Use those old races as spacers to push in the new bearing.
Bill D

[Kurt Wyberanec]

Hey all, finally got into the machine this week and here is what I discovered....

Could not tell where the noise was coming from...it was too loud and overwhelmed me to pin point it though I was inclined to say the Arbor....

Then I took the belts off...ran the motor and motor was very quite. Again ARBOR....

While inspecting the Arbor I could definitely find a place through rotation where there were 2 distinct click sounds one forward and then when turned back at a different spot. To me it sounded like a bearing but could also simply be something that was not set in place...

I discover that the allen screws that hold the pullys onto the shaft (or maybe they located on the keys) weren't tight....tightened those down and those clicks went away significantly....was the pully just not fitting snug against the shaft?

I put the belts back on fired her back up and ...........still noise, but possibly decreased.....next step....

I took them back off and tried to find this erroneous movement I mentioned and I really couldn't. I could feel it but it was not apparent where it could come from so I was starting to look at how can I remove the arbor to have the bearings replaced because surly that's what it must be. When I started looking around I said let's see what else there is here....the only other locking part I could see is the retaining nut on the end of the arbor shaft. It is a locking nut and likewise didn't think it could come loose but I decided to put a socket it on it and see if it moved.....and.....it did!! Not very much, probably not even an 1/8th of a turn, but it did snug up just a hair....turned the shaft by hand....clicking GONE!! Belts back back fired her up and noise level down tremendously. It's been making the noise so long that I can't quite remember how quiet this saw was before but it is much much less now.

So, did I fix it? I don't know, maybe, or might just be a band aid but for the moment my anxiety level can go down a bit. I am still going to upgrade, but maybe this worked.....My though is that perhaps there was just a minute amount of play on that shaft and it allowed either the shaft, pully, or keys inside to move that tiny amount and shift during rotation and maybe this snugged it....or maybe it just snugged worn parts closer together and works better for now.

Open to everyone's thoughts on this!!

[Jerry Bruette]

I'm not familiar with the Jet saw you have, but I'm having trouble visualizing the nut you tightened. Could you post a picture?

[Brian Runau]

Thanks guys, I will definitely do some of these checks and see what I can find. I am a light duty professional but it's a one man shop. My biggest challenge is that I haven't done much of this diagnostic work.....quick question though Brian, the noise I have is more of a raaaaaaa kind of sound not as high pitched as say a router running, but not exactly a grumble either. How would I be able to tell if the pulleys have somehow gone out of alignment? The saw did undergo a shop move about 2.5 years ago, but I can't recall as to when I started to notice the noise increasing....might have been before but at least a year now.

2nd question, if it is the arbor bearings, how does one replace them??? Can the arbor be removed and likewise brought to a shop to press them in (I'm assuming they need pressing)?

Thanks again!

Sorry fell off the planet a few days.

[Brian Runau]

I like to take the old bearings and grind the outer diameter down a tiny amount. Then take them apart and anneal the inner race and drill it out a fraction. Use those old races as spacers to push in the new bearing.
Bill D

Excellent tip. Brian

[Bill Dufour]

Sounds to me like the bearings wore a little and the preload was gone. Tightening the nut restored the preload. Yes I know ball bearing do not really have preload like tapered roller bearings but the same idea applies.
Bill D

[Kurt Wyberanec]

Sounds to me like the bearings wore a little and the preload was gone. Tightening the nut restored the preload. Yes I know ball bearing do not really have preload like tapered roller bearings but the same idea applies.
Bill D

I won't pretend to know a lot about how they work, but if my understanding is correct, what you said might very well be the case. If that's the case do you think that the preload spring would have to be replaced or would tightening the nut fix the situation or just extend the time? Thanks.

PS Sorry Jerry don't have a pic right now, it would be the nut that holds the arbor shaft and trunnion together.

[Mike Kees]

It will not be a permanent fix. The bearings need to be replaced. Tightening will be a 'bandaid' that helps for a while.

[Kurt Wyberanec]

It will not be a permanent fix. The bearings need to be replaced. Tightening will be a 'bandaid' that helps for a while.

Great........not what I was hoping to hear

[Bruce Wrenn]

Sorry fell off the planet a few days.

Over at NC Woodworker, there is a current thread on replacing bearing in your saw. The bearing you need will be 6203 2RS. A tip for heating bearings, use a light bulb. With bulb turned on, place bearing on top of it for about five minutes. Using leather gloves pick up bearing and drop on shaft.

[Kurt Wyberanec]

Over at NC Woodworker, there is a current thread on replacing bearing in your saw. The bearing you need will be 6203 2RS. A tip for heating bearings, use a light bulb. With bulb turned on, place bearing on top of it for about five minutes. Using leather gloves pick up bearing and drop on shaft.

I'll have to look further into this thanks... the biggest headache I can see is how to get the arbor mount out to even be able to change the bearings... really don't want to take the top off the table that can be a real pain to get back straight... so it goes

[Maurice Mcmurry]

Does anyone know how important it is to use a bearing heater during reassembly when replacing bearings? I have not used one. I have read and been told that to do the job properly a bearing heater is required. I have done several replacements that did not last nearly as long as OEM. I also see bearings with the same size numbers in price ranges from $10 to $100 dollars.

[Jerry Bruette]

Does anyone know how important it is to use a bearing heater during reassembly when replacing bearings? I have not used one. I have read and been told that to do the job properly a bearing heater is required. I have done several replacements that did not last nearly as long as OEM. I also see bearings with the same size numbers in price ranges from $10 to $100 dollars.

Depending on the size of the bearing you don't have to heat it to put it on. SKF makes a set of bearing drivers for mounting bearings up to about 2". If you're mounting a bearing on a shaft you drive on the inner ring, if you're mounting into a housing you drive on the outer ring. If the shaft is in a housing you would drive on both inner and outer rings. Any bearing over 2" should be heated and mounted onto the shaft. A little oil on the shaft or in the housing will help with the mounting process. Never use a anti-seize product for mounting bearings.

If you hang around the SKF website you'll find troubleshooting information and info on how to mount and dismount bearings the proper way. It'll also tell you the most common reason for bearing failure is improper or bad mounting techniques.