Makita Bearing went Bad

Hey Russel, hey Pat, hey all,

true, that looks like damage exclusively from wood dust. A clear indication of inadequate dust extraction.

You know that not only these bearings, but also the ball screws of the CNC machine are incompatible with wood dust?

As you can see on the fan blades, the fan sucks the air from the back of the machine (this is always the case, also on air-cooled spindles). Usually you should have no wood dust there.

How do you extract the dust from your CNC machine?

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Hey David,

which cooling system do you have? The cooling stations have a big fan.

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Hey Russel,

this can always be possible, but the wood dust here is not where it should be.

I have to wonder if the $6.00 bearing from Amazon is rated for high speed or even if the original bearing from Makita is as well?

For dust collection I use a Rigid shop vac here.
It’s used with 2.5" vacuum hose throughout and a cyclone separator.
I’ve used this the entire time.

You really thinks that’s it? Not enough vacuum?

What do you suggest for a proper vacuum?

Russ

Hey Russell,

a cyclonic dust separator always takes some suction power (even if you find it basically useful). I own a workshop vacuum cleaner with cyclonic separator too, but I don’t consider a workshop vacuum cleaner to be the right thing to extract the dust from stationary machines at all. They go with sanders and other hand tools etc. which always have an extraction fan inside, but on a CNC milling machine, like on a table saw or a thicknessing planer, you have to span larger distances when sucking.

(By the way, your link gives “Access Denied
You don’t have permission to access “http://www.homedepot.com/p/RIDGID-16-Gallon-6-5-Peak-HP-NXT-Wet-Dry-Shop-Vacuum-with-Cart-Fine-Dust-Filter-Locking-Hose-and-Accessories-HD1800/304795088” on this server.”
)

me personally, no vacuum at all. See here

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How did the dust ingress so badly?
The bearings are not in direct line of the airflow (both vacuum and the router cooling blades). The bearings had covers on each side. Not sure if this make them “sealed” bearings?

The route of the dust particles is around the complete bearing assembly…
BUT obviously the inside of the bearings are saturated with dust particles.

Can someone explain this?

I use this dust boot bought off Etsy: Dustimator © for Onefinity CNC - Makita RT0701C- (with magnetic removeable 2" bristles base).

My dust collection was not nothing. See my previous description of my dust collection.

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Hey Russel,

The air flow of the air cooling system of the Makita hand trim router sucks the air from the back (upper side) of the tool and lets it out on the collet side.

The covers protect from bigger particles but not from dust.

You disassembled this hand tool. Where did you see wood dust accumulated inside, along the described air flow?

One thing is clear, if you have wood dust in the bearing, it has not been sucked by your dust extraction system.

Well… will install the new bearing today.

What “dust collection lever” should I pull here?

  1. Better suction? Scrap the shop vac and go for a wall mount dust collector? What do most people use?
  2. Better dust boot?
  3. Spindle? Will a spindle be any better? Are spindle bearings sealed any better?
  4. ?

I didn’t notice more dust on one side or the other of the bearing after disassembly. BTW: The top smaller bearing is fine.
I would take very thin cuts with the flattening bit. After a flattening there would be no dust.

I bought Mechatron’s cooling station, but I set it in a cabinet beneath the CNC. The cabinet has no doors and is 24" deep, 60" wide. I could easily have positioned it further from the cabinet sides (and now have done so). I hope my problem was that the fan (at the back) and air intake (one of the sides) were both too close to the cabinet.

Hey Russel,

I can only say that…

I have no experience with it, but of course the selection of a dust boot can matter.

I have no personal experience with air-cooled spindles. One thing is sure, on a water-cooled spindle, there is no fan and no air flow through the device, and the cooling capacity does not depend on spindle rpm (like it does on air-cooled motors).

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Hey David,

then you have the same cooling station than me. But I don’t think you need anyone to tell you that you made a mistake by limiting the ventilation of your cooling station :slight_smile:

Why did you enclose it into this cabinet? Usually you would have to make sure heat can get away

Will you report what Mechatron replied? In the spindle manual it says 10 °C – 30 °C is allowed range and at 40 °C there should be the alarm triggering. In the cooling station manual it say it’s sufficient for spindles up to 5.0 kW.

Wow, what a great forum. Great discussions. An outstanding database of knowledge.

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Yes, I’ll pass along what they tell me.
Why in a cabinet? I wanted it beneath the CNC, both to avoid a tripping hazard and to mitigate dust entry. We could call it a cabinet or just a shelf, since it’s such a large space (20 cubic feet), open along the entire face. Either way, I should have given it more distance from the sides, and that’s easy to do.
The temperature never rose above 31 C, and the alarm never sounded. I assume the primary problem was ventilation, but I can’t be certain that faulty bearings were not the cause.
Certainly the protections (the alarm and the capacity to tolerate up to 40 C) were not sufficient to prevent damage.

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Hey David,

usually the best would be if the heat can flow upwards from the outlet. And of course that it can get fresh air to its inputs


Here’s an image of the cooling station in its ‘cabinet / shelf’

Hey David,

thanks for showing the photo!

I would not think that the positioning shown should make a problem. Or were the openings on the sides more to the wall?

Maybe there was another problem that led to the temperature rise? Do you use enough of their cooling liquid (9 liters)?

Cooling fluid level confirmed within specifications. The open face (during usual operations) is about 10" from a wall. But the most serious (former) problem was that the cooling station was turned 90 degrees, with the fan output toward the longest wall seen int the image. One side was much closer to the wall that separates it from the VFD enclosure (right side of the image). Attached is a photo of the front of the cabinet. The front and back portions are separated by a panel that runs the length of the cabinet.

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Hey David,

that could have been disadvantageous.

What a beautiful machine table you have! I envy you for this.

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Thank you. I made a torsion box, wrapped with ash wood taken from a tree my neighbor felled. The base is simple cabinetry made from a red oak I had to take down several years ago. The design was inspired by an outfeed table on YouTube: DownToEarth Woodworking.
I’m an amateur woodworker before I’m any kind of CNC expert.

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