Bearing heating?

[D._Frederick]

While doing some routing, I noticed that the bit and collect were hot to the touch. Did the bit heat up after about 10 minutes of run time, or do I have a bearing on its last legs?
The bearing is on a Delta over arm router and was built some time in the seventies, it turns free but could be short of grease. Delta will not sell just the bearing, they want you to buy the complete spindle since it is ground with the bearings as a unit. Would you try to replace the bearings yourself?

[Fla._Deadheader]

Is there any way to get TO the bearing??? Maybe try to pop the seal and grease it manually ???

[Sprucegum]

If your bit is getting dull it will heat up real quick. I would try a new bit first.

[D._Frederick]

Found that I have a rough turning bearing on the spindle. Delta is no longer having parts for this old of a machine. Will see if any bearing companies locally will have a bearing rated for 20,000rpm

[Dan_Shade]

Does it have a number on it?

sometimes industrial warehouses have a lot of wierd size bearings.  you could possibly get one from McMaster-Carr or MSC.

[D._Frederick]

On this machine, any saw dust can fall right on the bearing seal, I would guess that it has saw dust in the grease.  I will try Dead-heads idea and pop the seal off and see if I can save the bearing if the ball cage is not broke up. I  would guess that this bearing is in the $25 range. I will have to take the spindle out of the housing to read any numbers.

[D._Frederick]

We pressed the bearings off with an arbor press, have new bearings on order.

$50 for the pair.

[olyman]

kinda proud of those bearings, arent they???? course i have noticed--any high speed bearing gets costly!

[D._Frederick]

We got the new bearings pressed on to the spindle, they sure turn nice and smooth.

Running the router with no-load, the spindle and housing heat up hot enough that you can't hold a finger on them. This is the first time that I have worked on equipment turning 20,000RPM, I don't have a feel for how hot a bearing can get.

[Fla._Deadheader]

Are they belt drive, and maybe the belt(s), are slightly out of alignment, causing excess friction ???

[D._Frederick]

DH, This over arm router has a universal motor on top driving a spindle below that has two bearings with a coupling. I called up the bearing company and looked up the spec's on the bearings I got. Said that the grease the bearings are packed with is rated for 350 degrees F., so the heat should not be a problem. I didn't know that a non-friction type bearing would generate this amount of heat.