Help Needed, Table Saw Motor

[Stew Hagerty]

I have this Craftsman table saw from the 70's, and although it is far from new and only 1hp, I have never really needed more. I added a 50" Vega fence and large, heavy crank wheels to it a couple of years ago to make it more flexible and easier to operate.

Well, it has finally left me down... All of a sudden yesterday it had no power. It sounded different when it ran, and would barely cut pine without stalling. I did some research and found that a likely problem was the capacitor. So I located one and picked it up today, came home, and plugged it in and... No difference.

Now what? I thought about the brushes, but didn't read one place where that might be the problem.

Does anyone have any ideas? I would appreciate any help at all.

I really don't want to go buy a new motor unless I absolutely have to.

Speaking of buying a new motor though... Like I said, this is a 1hp, but could it be replaced with a 1 1/2 hp? I mean, if I would have to replace the motor anyway, could I up the power some?

[John TenEyck]

I have a 70's Craftsman with a 1HP motor, too. Never had a problem. It's an open drip proof motor. Is that what you have? The first thing I'd to is take the belt off it and see if it runs OK. Maybe one of your pulleys has slid and the belt is rubbing on something. It's happened on mine several times - the one on the saw arbor. If the motor still runs slowly with the belt off, then check the electrical connections to make sure they are tight. If they are OK, then it's probably a bad bearing. If so, you could take it to a local motor shop and they will be able to replace them, or you could do it yourself. It's really not that hard a job.

If you do have to replace the motor, a 1-1/2 HP will obviously give you more power, and be nice upgrade. As long as you can mount it and it's the same 3450 rpm it will work fine. When I have to rip thick stuff on mine I use narrow kerf blades, and have no trouble ripping 2" thick oak.

John

[Larry Komroff]

I would try blowing the motor out with air. There could be dust inside interfering with the centrifugal switch. That switch allows the motor to start with the capacitor in the circuit, and as the motor reaches operating speed, it removes the capacitor. That switch is mechanical and is usually located inside the rear housing.

Larry

[Stew Hagerty]

I would try blowing the motor out with air. There could be dust inside interfering with the centrifugal switch. That switch allows the motor to start with the capacitor in the circuit, and as the motor reaches operating speed, it removes the capacitor. That switch is mechanical and is usually located inside the rear housing.

Larry

Hmmm, I did read something about the centrifugal switch but I wasn't sure what they were talking about. I can't find a diagram of this motor anywhere. But I certainly can and will try blowing it out first thing tomorrow morning. Thanks for the idea Larry, I'll let you know if it works.

[John TenEyck]

I would try blowing the motor out with air. There could be dust inside interfering with the centrifugal switch. That switch allows the motor to start with the capacitor in the circuit, and as the motor reaches operating speed, it removes the capacitor. That switch is mechanical and is usually located inside the rear housing.

Larry

+1 Just came back to post that idea and saw your posting. I bet that's the real problem.

John

[Stew Hagerty]

Now this is interesting...

I just went out and blew out the motor through every vent available. Still no good.

So, I began preparing to remove the motor so I could take it in to a repair shop. Well what did I find??

The first thing I did when the problem cropped up was to check the belt tension, which was fine. Well, I didn't need to remove the belt cover to check that so I never saw this:

238177238176

Yup, one whole side of the pully is just GONE.

Now, I'm just guessing here, but I'm thinking this might possibly have something to do with my problem.

Anyone ever see anything like this; I know I certainly haven't. So... I guess I'm off to see if I can find a pully.

[Troy Turner]

Can't say I've seen a pulley do that. I have an 80's Craftsman. I did have my pulley come loose from the arbor. Still ran, but ran like crap. Make sure you get (if you can find) machined pulleys. Heard those will make a difference. And go ahead and replace both at the same time.

[Keith Hankins]

Can I suggest you go over to the old woodworking tools web site and post your question there in the everything electrical section. Those guys there are great with the old motors. I bet they can solve it and if it needs parts tell you how to replace it. Great group.

http://www.owwm.org/

[John TenEyck]

Now this is interesting...

I just went out and blew out the motor through every vent available. Still no good.

So, I began preparing to remove the motor so I could take it in to a repair shop. Well what did I find??

The first thing I did when the problem cropped up was to check the belt tension, which was fine. Well, I didn't need to remove the belt cover to check that so I never saw this:

238177238176

Yup, one whole side of the pully is just GONE.

Now, I'm just guessing here, but I'm thinking this might possibly have something to do with my problem.

Anyone ever see anything like this; I know I certainly haven't. So... I guess I'm off to see if I can find a pully.

Oh yeah, that's not so unusual with those cast pot metal pulleys. But 30 or 40 years isn't bad for a $5 pulley. Another cheap one will get you going, but if you also pony up for a couple of machined steel ones and put a segmented belt on it you'll be surprised how much smoother it runs. Glad to hear the problem was so simple - and cheap.

John

[Stew Hagerty]

Oh yeah, that's not so unusual with those cast pot metal pulleys. But 30 or 40 years isn't bad for a $5 pulley. Another cheap one will get you going, but if you also pony up for a couple of machined steel ones and put a segmented belt on it you'll be surprised how much smoother it runs. Glad to hear the problem was so simple - and cheap.

John

I checked and replacements are available from Sears (although there is a big note saying that they are an "equivilant" pully rather than the "same" pully. As for the segmented belt, I've been using une of those for years and you're right, they run so much smoother than a standard belt.

[Stew Hagerty]

Can't say I've seen a pulley do that. I have an 80's Craftsman. I did have my pulley come loose from the arbor. Still ran, but ran like crap. Make sure you get (if you can find) machined pulleys. Heard those will make a difference. And go ahead and replace both at the same time.

I did find replacement pulleys from Sears without spending a day running around so I ordered them. I figure these lasted 35-40 years so even if the replacements are pot metal, they cost just over $5 each so why not.

In the past I've had the driven pully come off it's arbor, or nearly so, a few times and getting in there to tighten the set screw is a PITA. But, until now, I've never had any problems with the drive pulley. Anyway, I am replacing both pulleys while I'm at it.

[John McClanahan]

The pulley doesn't look worn out. It looks like it developed a stress crack and broke. My guess is that the motor is not in true alignment with the blade pulley. When there is tension on the belt, the motor may hang a bit crooked, stressing the outer flange of the pulley as the saw is running.

[Stew Hagerty]

The pulley doesn't look worn out. It looks like it developed a stress crack and broke. My guess is that the motor is not in true alignment with the blade pulley. When there is tension on the belt, the motor may hang a bit crooked, stressing the outer flange of the pulley as the saw is running.

Good thinking John, I was wondering about that myself. I just received the pulleys so, when I replace them, I'll double check the alignment.