C-14 guide bearings all failed

tvrgeek

Scott
User
Only run a few hundred feet through my band saw and all 10 guide bearings are bad. Guess I get to see how good Harvey warrantee is. I set my guides pretty wide so that is not an issue. In inspection, they do not seem to be sealed. 8 sides are probably industry standard and I can get good ones, Rear guides look a bit odd ( offset).

Seems V-belts are not the only thing the Chinese can't make.
 

Phil S

Board of Directors, Events Director
Phil Soper
Staff member
Corporate Member
KFB from Germany. No comparison
 
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tvrgeek

Scott
User
I have identified them as 608RS, 8mm ID, 22 OD, 7mm wide and 689RS 9mm ID, 17 OD, 5 wide. Of course, quick source is Amazon, e-bay, and Alibaba, not the respectable brands.
@ 50 cents each, don't think these "skateboard" bearings are of high quality!
 
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junquecol

Bruce
User
I have identified them as 608RS, 8mm ID, 22 OD, 7mm wide and 689RS 9mm ID, 17 OD, 5 wide. Of course, quick source is Amazon, e-bay, and Alibaba, not the respectable brands.
@ 50 cents each, don't think these "skateboard" bearings are of high quality!
Better than the ones that came on your bandsaw. Price doesn't always corilate to quality. Put a $17 dollar bearing from NAPA in idler pulley on daughter's Honda. Lasted less than 3 months. Replace it with a $1.99 fom Fastenal, which now has around 300,000 miles on it. The $1.99 special out lasted the OEM bearing by a couple hundred thousand miles. Walmart used to stock skate board bearings in the sporting goods dept. Come in a tube of eight or ten the last time I bought some. Check out VBX bearings as a source.
 

tvrgeek

Scott
User
Found some 608 NTN. $6.80 each. Even if Harvey sends me new ones, I think I should get good ones and be done with it.
KFB (have not found a source)
NTN ( some on Amazon
SFK I think has a distributor in Burlington
NSK Source in England.

If one wonders why some tools are cheaper than others, well here is a good example.

I find several listings in this size for "ceramic" bearings. Seems the balls are ceramic. Good, bad. indifferent?
Don't know about idler pulley, but there is no way to make a decent ball bearing for $10 tube of 20.
 

Charlie

Charlie
Corporate Member
My bandsaw and lathe steady rest use 608ZZ. Purchased (3) 10 packs several years ago for .50 each. Still have 2 1/2 packs left.
 

Phil S

Board of Directors, Events Director
Phil Soper
Staff member
Corporate Member
Locate ball bearings.com sell almost all brands
KFB are used by Porsche, BMW and Benz - companies known for good quality
 

marinosr

Richard
Senior User
Wow, I'm really, really surprised that guide bearings would fail like that. That's one of the lightest duties I can imagine for bearings. I used Amazon (Penguin?) brand bearings on my bandsaw on the theory that they're going maybe 200 rpm max with a light axial load, and are running maybe 60 minutes total per year.
 

tvrgeek

Scott
User
Especially as I set my lower guides wide and one of them is totally seized.
Locate ball bearings.com sell almost all brands

KFB are used by Porsche, BMW and Benz - companies known for good quality

I might suggest the above auto many factures have more reputation and advertising than reality. Especially Benz.
 

cyclopentadiene

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My other hobby besides woodworking is skateboarding. There is a huge difference in the quality of bearings. I skate Ceramic bearings which are more spherical than steel, last longer and more resistant to build up of dust. They are 10x faster than any steel bearings. Asian made ABEC 7 bearings do not meet the standards of older 1980’s German made ABEC bearings. The ones with lower ABEC ratings are a waste of money.
if you decide to use skateboard bearings i recommend Reds Ceramic. They run $150 for a set of 8 compared to abec7 @$20. You get what you pay for.
 

tvrgeek

Scott
User
Thanks. I'll check them out. I am not familiar with ABEC ratings, so I will investigate. Ceramics seem to be more geared to higher speed than what we need for guides, but that may translate into "lifetime" for us. If course, I need 9 of one and one of the other. 608 seems to be a common skateboard size.

I find you don't always get what you pay for, but if you don't pay for it, you sure as heck won't get it. Off for more reading.
 

cyclopentadiene

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One other thing to check on the bearings. You should be able to remove the rear cover. Once removed, there is a plastic liner that fits between each bearing on the back side. This is easily removed and these are generally the culprit in cheap bearings. If you remove the plastic ring and soak the bearings in rubbing alcohol with a couple of drops of dishwashing liwuid, you can remove all of the dirt and grit. Use a high grade lubricant on the bearings and when reassembling, Leave put the plastic ring and replace the back dust cover. The bearings should function fine afterwards. The plastic retainer ring tends to be the issue as they break down and leave grit inside the bearings. They work fine without it
 

tvrgeek

Scott
User
OK, read up. ABEC neither addresses the things a border might worry about like impact and skew loads, just dimensional tolerance. Nothing about the grease, seals etc and nothing on durability under different conditions.

Comments from one SB supplier is their ceramic bearings are not well sealed and with lighter oil ( to have lower resistance for racing ) need to be cleaned and oiled. That would be a real pain as they are press fit and the lower ones hard to get to.

Removing the rubber seal and re-installing it without damage is easier said than done.
 

tvrgeek

Scott
User
Wow, I'm really, really surprised that guide bearings would fail like that. That's one of the lightest duties I can imagine for bearings. I used Amazon (Penguin?) brand bearings on my bandsaw on the theory that they're going maybe 200 rpm max with a light axial load, and are running maybe 60 minutes total per year.
Yea, just an oilite bushing might be a better design. I do not like that the thrust bearings sit in a chrome plated cap and the band chews it up. I would think the SS bearing case would be better by it's self. Maybe a ceramic block. I bet Space Age has one to fit.
 

Mike Davis

Mike
Corporate Member
I bought a tube of sealed permanently lubricated skateboard bearings for my Rikon bandsaw around the second year I had it. The original bearings were, I think, $17 a set of four. I got a tube of ten for $12.
Still on the first ones out of the tube, still have a set in reserve +2. Still doing what they are supposed to do.
I think I bought the saw in 2007 so the current blade guide bearings were replaced in 2009.

For the bearings to be worn out in a few months something is seriously wrong.
 

tvrgeek

Scott
User
No. I actually run my lowers very wide. I watch the uppers and only occasionally kiss a side. Thrust takes a bit more when re-sawing.
Got them all out and apart. The bearings are so cheap, they don't even have a manufacturer on them. Seals are molded in, so no way to really flush, but soaking got a couple to spin, poorly. The small 689 was actually a shielded bearing so I was able to flush it a little, but of course only put oil in it not thin grease.

There is a suppler about 40 miles away in Raleigh and there is an app to verify serial numbers have not been used before.

I want to see what Harvey says when I call them later today ( Pacific time). At least with a small mod, I can get the lower side bearings out without the entire bearing block. ( backed out the limit retaining screws.)
 

ShortRound84

ShortRound
User
My Grizzly bandsaw came with cheap shielded guide bearings as opposed to rubber sealed ones (RS I think). Almost all of the lower shielded guide bearings had seized from saw dust when I purchased it used. I haven't had a problem since I replaced them with cheap RS bearings. For my money, I don't think it makes sense to get expensive ceramic bearings as replacements in this application. The cheap sealed ones have worked fine for me for the past 3 years and I have replacements ready as this is a wear item in my view. Dust collection can also make a big difference obviously, especially with the lower bearings that get bathed in fine saw dust.

 

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