Bowl Bit Boom

[gMike]

I was using a bowl bit with a template when the guide bearing seized.  This makes for a very interesting experience in Maple.  The burn marks took a while to sand out.

The bearing was completely seized and had to be driven off the bit.  Kind of strange because I just touched up the bit and lubed the bearing a week ago.  I've done 2 other bowls since I sharpened the bit and they went fine.  Never seen one completely seize up before.  It's not a new bit so I can't complain too much.

[TomFromStLouis]

What lubrication did you use?

[gMike]

What lubrication did you use?

Boeshield.

[AHill]

Boeshield.

Boeshield is a nice protectant, but a poor lubricant.  It has paraffin as an ingredient.  If it got hot, then the wax will burn off, leaving you with almost no protection.  Likewise, WD40 is a poor choice for bearing lube.  3-in-1 is an OK choice.  Rockler and Woodcraft sell purpose-made router bit bearing lubricants.  PG2000 is one that comes in a handy tube with a hypo style applicator pen.

[MichaelMouse]

Bushings never seize.

[handi]

Bushings never seize.

While true, that is less than useful.

A bushing ONLY allows for a bowl bit to make a pocket as deep as the bit plus template.

A flush bearing allows the pattern to be cut, then the template can be removed and the bearing can ride on the previously cut wall to whatever depth can be reached. Done this many times.

[MichaelMouse]

Take away the template and use the new opening.  Get you a few more mm without the template.

For those of us using "bowl" bits as sort of oversize core box on trays, extremely useful to not worry about bearings.

[Steve N]

Wondering if it isn't more about the brand of bit, than the lube? Sounds like a shorts changing type moment



I had a Katana that self destructed, since I've stuck with CMT's or Whiteside's.

[Stwood_]

I usually stand the bit up in the vise, and put 3-in-one oil on the seal, letting it soak in, occasionally turning the bearing.

[daddo]

Related, in the case for motor bearings that soon seize or go bad after oiling, I theorize it isn't the oil that killed the bearing, but the beforehand lack of oil that caused minute particles of metal to form in the bearing where they free flow, but when oil is added, it makes a metallic paste of the particles causing them to gum the bearing up and/or cause more rapid friction and heat and wear.
I have oiled old motors that were running fine (but dry) and they failed soon after. I got to where I wouldn't oil old dry motors.
Boeshield isn't a lubricant for bearings as I understand it, but a metal protectant and leaves a dry waxy film- probably not good for any high speed bearing.
 Waxy surfaces will collect dust and debris. A nice regular 20w oil is fine.