Jointer Bearings Question

[Craig Meaney]

Hi everyone - I decided to replace the bearings in my DJ-20 jointer since I am putting in a Shelix and have it apart anyway. I purchased two bearings: Nachi 6005 2NSE9CM and Nachi 6005 2NSE9C3 for the replacement. I just pulled one of the existing bearings and it's a Nachi 6004 NSL. The difference between the NSL and 2NSE is that NSL has a contact rubber seal on one side, while the 2NSE has one on both sides. In theory this would be an improvement, correct?

Second question: the CM bearing has less radial clearance that the C3. Will this give me grief when trying to install the bearing or pose any other kind of issue? I haven't pulled that bearing yet, so I'm not sure what's in there.

Thank you in advance for your expertise.

[Richard Coers]

Since you never touch the outer race and seals when you install the new bearings, I see no problems.

[John Lanciani]

Well if your numbers are correct you have a bigger problem; a 6005 bearing is a different size than a 6004 bearing.

[Jerry Bruette]

Along with what John pointed out I would replace the bearings with a bearing of similar clearance. It's okay to change the seal type and number, two versus one, but I wouldn't change the clearance.

I've never worked on a jointer but will assume that the bearings get mounted on the cutter head and then the head gets put into the frame? If that's the case be sure when mounting the bearings to use the inner ring only, don't put any pressure on the outer ring. Most bearing failure is caused by improper mounting or not keeping them clean during installation.

[Greg Quenneville]

So you are saying that you bought two different class bearings as well as the wrong size? As above, get the right 6004 size in however many rubber seals as you like, and pay attention to Jerry's advice about mounting them. And use a clamp to mount them, not a socket and hammer.

[Jerry Bruette]

Driving a bearing in or on to mount it is acceptable practice so long as you drive on the proper ring. Mounting the bearing on a shaft drive on the inner ring. Mounting in a housing drive on the outer ring.

SKF makes bearing driver kits that drive on both rings at the same time. Don't think of buying for hobby or one time use, the set costs about $1000. It's acceptable to drive up to a 2" bearing.

Be sure to lube the shaft or housing with some oil before driving the bearing. Never use anti-seize compound.

[Dwayne Watt]

6004 and 6005 bearings are different size. 6004 is a 20 mm shaft and 6005 is 25 mm. The OD are also different on these bearings and are not interchangeable with one another. The C3 is an internal clearance value between the balls and the raceways. C3 is the most common bearing and will cause you no issue. Standard clearance bearings have slightly less internal clearance and will actually run hotter in grease applications. You really want seals, not shields, on both sides of both bearings. Open bearings on a jointer will fail in short order.
You can drive bearings onto a shaft without any special driver. You simply need to drive against the proper race (an appropriately sized socket or pipe works fine on these small bearings, no special tools needed). In other words, DO NOT drive across the bearing balls. More clearly, do not drive on the outer race when installing on a shaft or on the inner race when driving into a press fit housing. It is not necessary to put oil or never seize on the shaft but you can use either if it makes you feel better since this is a dry shaft/dry bearing installation. You never use never-seize as an assembly lube on a forced oil lube system such as a gearbox or engine. Also never used never-seize as a grease. It will fail near immediately.
If you can convince your better half to allow you to heat the bearings in the oven, then you can heat them to roughly 250F and they should literally drop onto the shaft or will at least drive easily. 250F won't hurt the grease or seals of even the lowest quality bearings.

[Bruce Wrenn]

Instead of the oven, heat them on a "redneck" bearing heater, AKA a light bulb. Because of energy requirements, you will have to buy a rugged service 100 watt bulb. Put bearing on light bulb for 7- 10 minutes, and it will heat tit up. Be sure to wear leather gloves when you take it off light bulb, as it WILL BE HOT!

[Bill Dufour]

I take the old bearing and hold it to grind the outer race od down a few 1/100ths. then I take it apart and heat the inner race to redhot, let cool, then drill the inner bore a few 1/100ths larger.
Now I have perfect size drivers for inner and outer races.
Bill D

[Brian Runau]

The industry standard for American market electric motors is a C3 fit. The CM fit would be a tighter fit between the races by either using difference sizes races or using a larger ball bearing to accomplish the fit. The CM provides less slop while the bearing is running so conceivably less runout in the cutter head of the machine. I don't think it is necessary in a piece of woodworking equipment, but I only play an engineer, not degreed. The CM fit would generate more heat during operation so this may be why they sacrificed potential contamination for one side being open to better allow the bearing to dissipate the heat it is generating. The open side is away for the center of the machine and may not be directly exposed to saw dust.They also may have done this to force the user to come to them for replacement bearings.

It's all about calculating speeds, heat, life, etc... which is all over my head. Honestly don't see why you can use a standard C3 double sealed bearing, less expensive more common/available on the market.

NSL VS NSE looks to be how the rubber is attached to the metal shield on the bearing. See file attached.

Brian

[Matt Day]

Getting way too complicated with all those numbers for the bearings, for a hobby woodworking machine. Order up some generic rubber sealed 6004 or 6005 bearings for $10 a piece and have at it.

[Eugene Dixon]

At one time, I knew of a bearing distributor that had a customer service representative that focused on woodworkers. Wish I could remember. She was very good at explaining bearings.

[Craig Meaney]

Well if your numbers are correct you have a bigger problem; a 6005 bearing is a different size than a 6004 bearing.

They're the correct sizes for a DJ20. The pulley side bearing of the cutterhead is larger that the other side.

[John Lanciani]

They're the correct sizes for a DJ20. The pulley side bearing of the cutterhead is larger that the other side.


Well your initial post said that you bought two 6005s and removed a 6004 from the machine. :rolleyes:

"I purchased two bearings: Nachi 6005 2NSE9CM and Nachi 6005 2NSE9C3 for the replacement. I just pulled one of the existing bearings and it's a Nachi 6004 NSL"

[Cameron Wood]

I take the old bearing and hold it to grind the outer race od down a few 1/100ths. then I take it apart and heat the inner race to redhot, let cool, then drill the inner bore a few 1/100ths larger.
Now I have perfect size drivers for inner and outer races.
Bill D


I hope this is a joke!

[Craig Meaney]

Well your initial post said that you bought two 6005s and removed a 6004 from the machine. :rolleyes:

"I purchased two bearings: Nachi 6005 2NSE9CM and Nachi 6005 2NSE9C3 for the replacement. I just pulled one of the existing bearings and it's a Nachi 6004 NSL"

Oh crap. I mistyped what I bought. Sorry!

[Bill Dufour]

I hope this is a joke!
No joke. Now I have a lathe and if time allows I will still do this rather then make drive rs out of mystery metal. you prefer deep sockets or pipe nipples
that are sorta close?
Bill D

[Richard Coers]

I take the old bearing and hold it to grind the outer race od down a few 1/100ths. then I take it apart and heat the inner race to redhot, let cool, then drill the inner bore a few 1/100ths larger.
Now I have perfect size drivers for inner and outer races.
Bill D
A few 100ths can be 1/32". Did you mean 1000ths?

[Bill Dufour]

Honestly I have never measured it. Just grind enough off that all the original polished surface is gone. It is probably 0.001ths like you say. I have never seen a bearing without rounded over edges to inner and outer race so no need for the driver to be full diameter anyway.
Bill D

[Maurice Mcmurry]

I take the old bearing and hold it to grind the outer race od down a few 1/100ths. then I take it apart and heat the inner race to redhot, let cool, then drill the inner bore a few 1/100ths larger.
Now I have perfect size drivers for inner and outer races.
Bill D

Thanks bill, Adding that to my bag of tricks! When Jet sent the factory a replacement cutter head I was pleased to find that it arrived with new bearings already pressed on.

[Bruce Wrenn]

At one time, I knew of a bearing distributor that had a customer service representative that focused on woodworkers. Wish I could remember. She was very good at explaining bearings.Lynn at Accurite Bearings, if memory serves me correct.

[Craig Meaney]

Thanks Brian. Should I return the CM bearing and get a C3 instead?

Craig


The industry standard for American market electric motors is a C3 fit. The CM fit would be a tighter fit between the races by either using difference sizes races or using a larger ball bearing to accomplish the fit. The CM provides less slop while the bearing is running so conceivably less runout in the cutter head of the machine. I don't think it is necessary in a piece of woodworking equipment, but I only play an engineer, not degreed. The CM fit would generate more heat during operation so this may be why they sacrificed potential contamination for one side being open to better allow the bearing to dissipate the heat it is generating. The open side is away for the center of the machine and may not be directly exposed to saw dust.They also may have done this to force the user to come to them for replacement bearings.

It's all about calculating speeds, heat, life, etc... which is all over my head. Honestly don't see why you can use a standard C3 double sealed bearing, less expensive more common/available on the market.

NSL VS NSE looks to be how the rubber is attached to the metal shield on the bearing. See file attached.

Brian

[Brian Runau]

Thanks Brian. Should I return the CM bearing and get a C3 instead

Craig

Without knowing why they designed it the way they did, I would be reluctant to change it. At worst you would get a little shorter life. Brian

[Cameron Wood]

No joke. Now I have a lathe and if time allows I will still do this rather then make drive rs out of mystery metal. you prefer deep sockets or pipe nipples
that are sorta close?
Bill D


I though that you were saying that after annealing/grinding, you reassembled and used that bearing- my bad.

[Tom M King]

One place I'm good with cheap Chinese tooling is bushing and bearing press kits, and a hydraulic shop press is good for many things.

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