Convection blower bearing replacement.

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Jason Knapp

Burning Hunk
Dec 11, 2012
237
Poughkeepsie, NY
I thought I read a while ago that there was someone on this forum who replaced Fasco blower motor bearing with a better quality bearing. Any idea who that might be?
 
The bearing I need: NMB 608SSD21. I need 2 of them but would prefer a better quality piece.
 
Those bearings are very high quality stainless steel.Must be a convection fan.You can get cheaper ones,but may be noisy.Look for german or japan made.Some of the manufactures are having the smaller bearings made in china for cost,but still offer the higher quality.Hope this helps
 
The ones I have now are made in Singapore. They didn't last too long. Im hoping to find really good ones. Ill Google it and see.
And yes its for a convection blower. There was someone on this forum that offered a replacement service.
 
I have standard german 608 sheilded,no stainless.You may be able to get bosch bearings at fastenal.Or look for router bearings.
 
I was able to find a 608 bearing through SKF. It's an ABEC 1 rated unit, so I think it can handle 2500 rpm easily.
 
I have a bunch of 608's but yours was ss-stainless steel.ABEC 1 is the lowest rating for tolerance.Most convection and combustion 608's I have seen are abec 3.If you do not mind shielded instead of sealed go to ebay,look for gmn "old school skate board bearings".These were made in the 80's-90's before skateboard bearings were made-low rolling resistance.These are german new old stock,and you can get a handful for $10.These came stock in austroflamm motors.They are 608-gmn-3.ABEC 3 which is a trade off of tightness yet allows for heat expansion.They are not stainless steel
 
There are a lot of the NOS 608's!
Do you have to lube them? If so, what do you use?
I ordered a set of sealed greased units to see how it goes. Yes they are only ABEC 1, but given that they wont see a ton of axial load, I was thinking they may be OK. Also the looser tolerances may be more tolerant of heat. Just my thinking. I have the time to mess around and see how it goes. Thanks for the input. I will keep you posted.
 
The looser tolerance bearings would do well in the combustion blower but IMHO won't see much heat on the convection blower so you're probably OK on the ABEC 1.
Note to self> file this one away for future reference.
 
Is it ok to cut the little buggers off the shaft? I don't have a puller that small.
 
If it's a small nick you should be fine. You can cut it close to the shaft and hit it some it might loosen enough to pull it.
 
The looser tolerance bearings would do well in the combustion blower but IMHO won't see much heat on the convection blower so you're probably OK on the ABEC 1.
Note to self> file this one away for future reference.

I am ceratinly hoping so. As far as temps, this blower gets HOT! I put some heat shielding around it which seems to help, but I would like to replace the bearings in the original unit so it,s ready to roll if I need it.
 
There are a lot of the NOS 608's!
Do you have to lube them? If so, what do you use?
I ordered a set of sealed greased units to see how it goes. Yes they are only ABEC 1, but given that they wont see a ton of axial load, I was thinking they may be OK. Also the looser tolerances may be more tolerant of heat. Just my thinking. I have the time to mess around and see how it goes. Thanks for the input. I will keep you posted.
Yes they are grease packed-the german ones-which is why skatboarders no longer use them,they are using oiled bearings.
 
I am ceratinly hoping so. As far as temps, this blower gets HOT! I put some heat shielding around it which seems to help, but I would like to replace the bearings in the original unit so it,s ready to roll if I need it.
ABEC 1 are looser,higher the number closer the tolerance,hence less noise and vibration,but less able to deal with expansion,3's standard for most blowers,5 or 7 for precision equipment.
 
I would use a Dremel type 3/4" cut off wheel to cut such a small bearing very easy to control.
 
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ABEC 1 are looser,higher the number closer the tolerance,hence less noise and vibration,but less able to deal with expansion,3's standard for most blowers,5 or 7 for precision equipment.
Bob- I always thought it'd be nice to live in the Rocky's It sure is scenic there! And Helena forest is close as well as some others, Nice!
 
I thought I read a while ago that there was someone on this forum who replaced Fasco blower motor bearing with a better quality bearing. Any idea who that might be?

I have to ask. How did you ever get the squirrel cage off?

I assume your Fasco blower has a squirrel cage. I have about three Fasco blowers sitting in the garage that need bearing replacement but I'll be damned if I can get the set screw loose. Whenever I try it looks like my allen wrench is going to break.
 
Is it ok to cut the little buggers off the shaft? I don't have a puller that small.
If you are replacing bearing on your Greenfield double squirrel cage fan you can use a large puller. I just did this on mine and used my 2 jaw puller that has larger jaws. I had to hold the jaws under the bearing to keep them from slipping off but it worked. It does not take much effort to get them moving, I did not even have to use a wrench on pulled. They only need to come up about 3/4 inch before they are free on the shaft. I bought a 1/4 inch by 5 inch brass pipe nipple to drive bearing back onto shaft. Fits perfect so you are not driving against the plastic grease seal.
 
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I have to ask. How did you ever get the squirrel cage off?

I assume your Fasco blower has a squirrel cage. I have about three Fasco blowers sitting in the garage that need bearing replacement but I'll be damned if I can get the set screw loose. Whenever I try it looks like my allen wrench is going to break.

I used a little bit of heat on the set screw and it was easy from there. It took a little elbow grease to get the cage off of the shaft, but it came free without damage.
 
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