Bearing suggestions

[MalcolmH]

Anybody have a #608 or #1605 bearing type they like to use for rebuilding electric motors, I recently tried a SKF #608-2RSH I think it was, deep groove bearing, and I guess it is more for skateboards or I got a bad one and they became noisy after an hour, anyone tried the #608ZZC3EMQ, I like the idea of using shielded bearings, but not enjoying doing the job 2 or 3 times. The bearing I removed from a convection motor was #608SSD21, always wondered why they did't use ZZ type bearings in a stove that may see heat and sawdust.

SKF

www.skf.com

 

[SidecarFlip]

Open race ball bearings won't work as a rule because the operating atmosphere contains abrasive dust (fly ash). The have to have dust shields which means they are pre lubed, open race bearings aren't usually pre lubed except for a coating of light rust preventive. Last time (long time ago) when I replaced a set, I just took the old bearings to the local bearing distributor (in my case Detroit Ball) and matched them. Dust shielded bearings will have either a metal or plastic shield whereas a 'sealed' bearing will have a pressed into the inner race, non removable shield and are at least 3 times as expensive as a dust shielded bearing. Stove manufacturers 'don't' because they buy the motor, gearbox assemblies and distribution, combustion fan assemblies pre built by another supplier, no stove builder makes those, all bought elsewhere (sub assembly) just like automobiles or anything else and those contractors use the least expensive components for maximum realized profit (just like automotive) again. You'll never see a hermetically sealed bearing in an OEM drive. Not to say you cannot refit because you can, but, the cost will be consequential.

 

[MalcolmH]

Ya I'm not referring to open race bearing for this application that wouldn't work to well here, the ZZ is a metal shielded sealed bearing, all sealed bearings are pre-greased, the 608-2RSH is a sealed bearing, I use a 1605-ZZ on a bandsaw for the guides and many other tools as recommended for an abrasive environment, the problem is the deep groove ZZ is not a quiet bearing and can resonate thus the reason for 608-ZZC3EMQ specifically designed for that application and quiet operation, open race would be for engine application where the bearing is oiled constantly. I know enough to not ask a bearing shop to bring in a bearing without ordering a bearing for the correct application, and have had them match incorrect applications before, I used to supply bearings for highway sanders and rolloffs so have some experience specing bearings for Load, speed, seal type, application but not these lil motors. I just thought someone might have a preference they use and have had success.

 

[SidecarFlip]

Don't get into catalog nomenclature at all except for ABEC class bearings for precision tool spindles. The rest I just take to my local supplier and do a direct cross at the will call counter.

 

[tlc1976]

I was recently sourcing bearings for my washing machine. My understanding is that zz is mainly a trash guard, where 2rs is a much better seal to keep grease in and water and fine dust out.

After hearing questionable things about SKF, I went with FAG bearings because I heard they are some of the longest running high quality units. I bought some off eBay with photos of the outer race etched with Italy or Germany. I realize you can label anything (like on the movie Tommy Boy) but it makes me feel better that they didn’t say China and so far so good.

I would look into higher temperature units for a pellet stove. Like high temperature grease with viton seals.

 

[SidecarFlip]

That increases the cost exponentially and if you actually maintain them with frequent lubrication like I do, not much point in reality Myself, I'd never replace a bearing in a stove that is hermetically sealed, one, because the cost and two, because I can oil them (dust shielded).

I'm going on 21 years on all mine with no replacements ever. End of season, all my drive components get taken out of the stove, benched, cleaned and lubricated and reinstalled so the following fall, everything is good to go.

The kingpin bearings on my FWA farm tractors are hermetically sealed and they still fail. Not the bearing but the kingpins themselves. You don't even want to know how much those bearings cost, lets just say, for a pair I could buy a new stove.

 

[gfreek]

I use the 608-ZZ- 3123 C3 or the 2RS plastic shield bearings in my combustion motor application..

 

[MalcolmH]

I've heard FAG is commonly used in these applications with good success. Well I must have got a bad Made in Italy SKF #608-2RSH or my press work was shoddy, they have the rubber seal that is "non serviceable permanently sealed 2RS" unless you pop the seal out and grease them, I put in another pair and it is a lil less noisy then the 16 yr old bearings that came out, but not as quiet as I'd like on a variable speed convection blower. That is also why I wanted to go with the ZZC3EMQ, the shield on ZZ are completely non-serviceable but one might be able to add oil although like said perhaps allow fine dust in. Always wonder what everyone is oiling on a sealed 2RS bearing, from what I've seen it just attracts dirt and dust insulating the armature, the only way to oil or grease most electric motors in pellet stoves is to disassemble remove bearing and seal and add grease or oil. I'll look into a Quiet #608-2RSC3EMQ as oppose to the ZZ style since these bearings are difficult at best to access and remove on this stove. Your standard 608 bearings are usually like skateboard bearings and have very loose tolerances and are noisy made of steel.

Perhaps I should look further into crossing over the original Made in Thailand NMB 608-SSd21 that came out of a Made in USA Fasco motor these are made of Stainless Steel, NMB also seem to be common place for this application, it looks like SKF 608-2RSL is a direct cross over or Timken 38KDD. The 2RSL has a higher limiting speed than the 2RSH but none of those are SS. Thanks for everyones input.

 

[rona]

Ya I'm not referring to open race bearing for this application that wouldn't work to well here, the ZZ is a metal shielded sealed bearing, all sealed bearings are pre-greased, the 608-2RSH is a sealed bearing, I use a 1605-ZZ on a bandsaw for the guides and many other tools as recommended for an abrasive environment, the problem is the deep groove ZZ is not a quiet bearing and can resonate thus the reason for 608-ZZC3EMQ specifically designed for that application and quiet operation, open race would be for engine application where the bearing is oiled constantly. I know enough to not ask a bearing shop to bring in a bearing without ordering a bearing for the correct application, and have had them match incorrect applications before, I used to supply bearings for highway sanders and rolloffs so have some experience specing bearings for Load, speed, seal type, application but not these lil motors. I just thought someone might have a preference they use and have had success.

I got pretty good at replacing bearings after buying them on E-bay. The least time I went to a motor rebuild shop and they have lasted five years so far. They cost more but some times you get what you paid for.

 

[SidecarFlip]

If you aren't handy with doing it yourself.... I am.

 

[MalcolmH]

Conclusion: The SS refers to a contactless rubber seal on both sides to avoid drag, it is believed the D21 refers to tolerances and lubrication viscosity for light load application but couldn't find it in writing. I got made in Singapore NMB 608-ssd21 and the fan is way quieter and faster/efficient than it was with brand new 608-2rsh skate bearings, research says the next closest thing would be 608-SS or 608-ZZ (contactless shielded bearing). The 608-SS and 608-SSD21 will be found in almost every electric motor on these stoves from Auger, combustion and convection, and many other electronic motors and fans on wood stoves like my Regency. The SSD21 made my Windsor run extremely quiet, which is rare for any pellet stove. So now we know why every Fasco electric motor in pellet stoves uses these bearings.

 

[SidecarFlip]

Consider yourself fortunate you don't have to purchase ABECC Class ZZ spindle bearings. I just rebuilt the spindle on one of my vertical mills and the each bearing was 150 bucks x 6. and they aren't shielded at all, open race with external lubrication. I installed SKF's. made in Germany. Bearing tolerances (runout) is +- 0.00002

 

[SidecarFlip]

I got pretty good at replacing bearings after buying them on E-bay. The least time I went to a motor rebuild shop and they have lasted five years so far. They cost more but some times you get what you paid for.

Most times on bearings, that applies. bearing standardization has become a fine art.

 

[mannion]

Conclusion: The SS refers to a contactless rubber seal on both sides to avoid drag, it is believed the D21 refers to tolerances and lubrication viscosity for light load application but couldn't find it in writing. I got made in Singapore NMB 608-ssd21 and the fan is way quieter and faster/efficient than it was with brand new 608-2rsh skate bearings, research says the next closest thing would be 608-SS or 608-ZZ (contactless shielded bearing). The 608-SS and 608-SSD21 will be found in almost every electric motor on these stoves from Auger, combustion and convection, and many other electronic motors and fans on wood stoves like my Regency. The SSD21 made my Windsor run extremely quiet, which is rare for any pellet stove. So now we know why every Fasco electric motor in pellet stoves uses these bearings.

Is it possible to remove the seals on the 608SSD21 bearings?

I have a Travis Large Flush Wood Insert stove, which has two fans to circulate the room air. Each has a pair of NMB 608SSD21 (Thailand) bearings to hold that shaft that goes through the middle of the electric motor.

In my opinion, these bearings are noisy to start, and get intolerable after a couple of years. Since I've owned this stove (8 years) I've replaced individual bearings, as well as whole motors. The expense has been nontrivial, whether measured by my time, parts (bearings, motors), or specialized tools (gear puller, bearing retainer glue).

I've never been satisfied with the noise level of any of these bearings. They are, however, better when they're new. I'm assuming that they'd also be better if they were freshly cleaned/lubed, too, but I cannot figure out how to get the seals/shields off for cleaning, if that's even possible.

Both bearings on both motors are to the point that I can barely tolerate to be in the same room as them anymore, so I figured I'd try again in earnest to remove one of the seals, even if that means damaging it. These look like they have removable rubber seals like my rollerblades, but after scratching at it for a while it appears to be a rubber coating over a metal shield. I'm not sure if there's a C-clip under there, or if the metal is permanently pressed in, or what. I'll attach a photo of where I removed some of the rubber to expose the metal shield underneath.

If anyone knows how to remove the bearing seal for cleaning, I'd appreciate your advice. Thanks!

 

[tlc1976]

Most likely the seals are pressed in. Probably no way to remove them without destroying them.

I just lube mine with 5w30 synthetic motor oil. Suck some up with an animal syringe and put it in the seal area with the bearing held flat. Rotate the bearing and it will draw the oil in. The oil breaks up any accumulated junk that leads to roughness or noise. Which is what I dealt with the first time or two because they were full of old grease. I get almost a season out of an oiling.

You could probably use petroleum based solvent and spin the bearing to suck it in and dissolve any junk. Then suck in some oil and be good to go.

 

[Mt Bob]

Work a small pick tool under the seal, on the inside edge(inner race), Or a stout pin or needle. Try not to damage the rubber. Work around,pry up.Once enough pressure is relieved, the outer edge will pop out,and you are good to go. Sometimes the metal (the rubber is coating it) will bend, which is OK, easy to put on a flat surface and tap flat, sometimes with a socket and mallet.

 

[Mt Bob]

And the seals go back in way easier than removing.

 

[MalcolmH]

Use the tip of a razor on the outer edge of the shield and pry up, its easy to deform it. They use a very thin grease, personally I'd just replace the bearing if its noisy as it will just come back. The inner part of the shield is the seal, you do not want to damage that.

 

[rona]

If you aren't handy with doing it yourself.... I am.

As I get older I have found a new friend named Art Ritus. as a result fingers dont bend and I find myself not handy with do it yourself items. Enjoy your health