Help removing a bearing ( electric motor, non-boat )

[Dusty Yevsky]

Sorry for the non-boat content but I do use this tool to build boats. I've got an old USA-made DeWalt miter saw, DW 705 type 3, that's about 28 years old. The main bearing on the armature seems to have gone south with lots of unhealthy vibrations in the blade when powered up. I stripped the motor down and removed armature but don't see an obvious way to remove the bearing from the shaft. The problem is that the bearing is sort of recessed into the fan (see pic below). My bearing separator is flat on the back and can't get behind the bearing due to the fan. The only thing I can think of is a couple of flat blade screwdrivers levering off the fan. I'm hesistant to try this because the plastic fan is old and probably brittle. The armature is listed as discontinued in all the part replacement websites so breaking it means trashing the saw.

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I'd really like to keep this saw going. I've got a Chinese-made DeWalt 12" slider and there is no comparison in accuracy and repeatabilty. The DW 705 is one the best tools I've ever owned.

So does anyone have ideas? I'd love to hear them all.

P.S. I checked the DeWalt website for a nearby service center. After the reading their claim of the most extensive service center network in the industry, their search function returned zero service centers in the North Jersey/NYC area. hah.

[Rumars]

Cutoff wheel on a dremel and a lot of care. Two cuts, 180° apart, no need to cut completely trough, split with a cold chisel works.

[Canoeyawl]

You need a bearing splitter and puller, if you don't want to invest in these tools hire someone that has them.
This is routine, splitters and pullers come in every size imaginable

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[Stiletto]

I would use a Dremel because that is what I have. I found this youtube video that specifically mentions the closeness of the fan: Good luck!

[Ron Williamson]

For a start,maybe clamp the bearing firmly in a vise,then rap on the gear end of the shaft.
Use a block of hardwood or brass rod as a cushion( and better aiming point)
Don't forget to support the armature so it doesn't drop out of the bearing and smash the fan anyway.
R

[sp_clark]

Use your Dremel to carve two notches on opposite sides of the outer race that will give a bearing puller something to get a grip on as though it were able instead to fit under the bearing. Tedious process but should take less effort than cutting radially through the entire bearing, with less risk to that plastic fan. Dremel's wheel will be parallel to fan at all times rather than perpendicular. If the outer race collapses during removal, do the same to inner race once it's exposed.

Start looking for replacement bearings now! Should be fairly easy if you can read the bearing code #'s on the shielding in between inner & outer races you've exposed on the gear end.

[Peerie Maa]

Cutoff wheel on a dremel and a lot of care. Two cuts, 180° apart, no need to cut completely trough, split with a cold chisel works.

^ This
KISS.

[Dusty Yevsky]

Thanks for all the good replies, very helpful. I do have a bearing separator as pictured but for some reason DeWalt recessed the bearing into the fan preventing access to the back.

I'm going to try sp_clark's suggestion of parallel cuts with a Dremel to provide a gripping surface. Now I just have to go out a buy a Dremel.

[Ethan]

For a start,maybe clamp the bearing firmly in a vise,then rap on the gear end of the shaft.
Use a block of hardwood or brass rod as a cushion( and better aiming point)
Don't forget to support the armature so it doesn't drop out of the bearing and smash the fan anyway.
R

I’d bet this would work. Could also try some taps on the shaft end with the top of the vise jaws supporting the back of the fan. Intent would be to shift the the entire fan/bearing assembly towards the gear end. You could then maybe push the fan back a few mm to open up space between the two which’ll facilitate slipping your splitter behind the bearing.

personally, I’d be leery about using a cutting disk next to that plastic fan. But that may be my lack of skill talking…

[sp_clark]

personally, I’d be leery about using a cutting disk next to that plastic fan. But that may be my lack of skill talking…

That's why I suggested cutting grip slots in the outer race for a puller. Cutting crosswise on outer race puts fan at risk if something slips. That plastic's old, maybe rather brittle, deserves every bit of care & respect one can muster. Once you get purchase on it w/puller that bearing should come off pretty easy.

[anomoly joe]

Safer to cut it off at a low angle with the Dremel. Last thing you want to do is futz up the worm gear.

Take your time. Wear eye protection. and i like sound protection cause it' less stressful.

The inner ring might be tricky to cut completely, but even cutting partially through will relieve stress and make it easier to prise off.

[Doctor J]

I thought I had successfully replied, but can’t find it in the thread. Try this: clean all the grease from the worm gear, get some dry ice (cheaper than a Dremel), wrap it in a dishrag (wear gloves), then wrap it around the worm gear. Wait for the shaft to get cold(maybe 10 minutes) and there’s a good chance you can pull the bearing off with your hand.