Table saw starts rough

[Andy Lee]

Greetings, I'm new here and glad to be part of the community.

I have a 10" Craftsman table saw (120V single phase direct drive), it's been working fine for about 3 years but lately it's developed a problem. It has a lot of vibration and noise when starting up. I mean enough vibration that the blade height adjustment shifts, and a pencil or small object left on the table gets jolted off. The vibration lasts about one second, once the blade is up to speed it works normally and cuts fine.

Removing and replacing the blade didn't help. The blade looks fine, no defects, and the motor shaft turns smoothly. I tried some compressed air on and around the motor to blow out any sawdust, it helped a little but after a few miter cuts the vibration was back.

Any ideas on what's happening? Thanks very much,

-Andy

[Carroll Courtney]

Welcome to SMC,its a great place----Carroll
Sorry just seen the direct drive,never have own one,but will follow this post

[Ray Newman]

IIRC, the direct drive saw is basically a hand-held circular saw mounted in a cabinet??

If that is the case, the saw mounting bolts and other bolts could be loose or the bearings are worn.

[glenn bradley]

First off; Welcome. The symptoms make me think bearings. Unplug the saw, remove the blade and take the arbor shaft between your thumb and index finger. Gently apply pressure in and out, up and down. If there is a noticeable shifting there may be a bearing issue.

This could be an opportunity to take the price you originally paid for the saw, divide that by the number of hours you have used it and see if the result indicates it is time for a repair or an upgrade ;-)

[Don Alexander]

definitely sounds like bearings however..................... i have this belief in the KISS principle hehe

KISS = Keep It Simple Stupid

that would suggest that checking all the nuts and bolts would be worthwhile

seems like everytime i ignore the little simple stuff when troubleshooting thats is what it turns out to be Murphy and his goofy laws

[Neil Davie]

A motor can start rough if the start capacitor contacts are dirty or missadjusted. Just a thought.

[Lee Schierer]

As others have stated look for loose bolts or worn bearings. I would also check to see if there are oil ports (little plastic plugs) on each end of the motor that can be pulled out to lube the bearings. Belt drive Craftsman saws have them.

[John Thompson]

Old hat at this point but I would also check the belt along with the mount bolts even though the symptoms sound likely to be bearing and especially on a direct drive.

Good luck...

[Andy Lee]

Thanks for all the replies so far!

The mounting bolts were tight, and although I don't have a dial indicator I tried to check runout with a caliper / depth gauge. Runout is less than +/- .005.

I was wrong about one thing in the original post. The blade is not ok, it's dirty. There are streaks of tar/pitch/goo on both sides, and a combination of the stuff and fine sawdust stuck to many of the teeth. I wonder if this is making the blade unbalanced?

Glass cleaner and rubbing alcohol could not remove the mess in a short amount of time. Maybe soaking the blade in something will do better, or maybe its time for a new blade? I'll try a new or cleaner blade, and update.

[Ray Newman]

To clean the blade, try oven cleaner or let it soak in a strong solution of Simple Green.

When you haver it clean, take it outside in bright light, place a finger in the arbore hole and slowly rotate it. If you see light reflecting off the teeth, it is dull and needs sharpening.

[Ted Baca]

Since you have checked the runout on the arbor and the mounting bolts are tight. I would look at two items of concern. One is simple, can you remove the motor and blow it out with compressed air? Many years of usage and not doing this may have dust caked up and if it has gotten hot enought the dust may have cooked onto the armature casuing the inbalance. Second is the motor is in need of brushes, bearings and if that is the case just replace the motor. And as mentioned above examine the economics of replacing the motor or the saw. I seriously doubt that the blade is that unbalanced to cause this issue. The pitch build up would be fairly even across the surfaces of the blade as it collects the pitch while it is spinning. One other item comes to mind is how secure is the saw? It may be amplifiing the vibration because the saw cabinet is not tight.

[Andy Lee]

Good points. I removed more gunk off of the blade, unfortunately the saw still starts with a lot of vibration.

Since we've already checked the bearings, blade, and motor mounting, the next item is the motor/arbor assembly. That'll have to wait for a weekend.

Peace,

-Andy