Vintage Craftsman tablesaw severe vibration

[ken kimble]

I have a 1964 craftsman 100 tablesaw which I bought new. I've recently replaced bearings and added other refinements. Since then the saw ran really well. Recently and suddenly the saw started shaking severely, as if something really out of balance. I replaced the motor (Baldor- arm and a leg) but no joy. I've checked the trunnion bolts- they are tight. Th c-clip is still in place on the arbor pivot. I'm stumped. Anybody have suggestions. (I have a link belt on it.)

[scott spencer]

How do the pulleys look? I'd remove the belt and run it....if it's still vibrating, look for something to do with the motor/motor mount. If not, check the arbor, bearings, blade, arbor nut, etc.

[Chris Hachet]

How do the pulleys look? I'd remove the belt and run it....if it's still vibrating, look for something to do with the motor/motor mount. If not, check the arbor, bearings, blade, arbor nut, etc.

Pretty much this. I also do not like link belts, AX type belts work better in my experience.

[glenn bradley]

I also vote for pulleys. And not to be confusing but, I love link belts. I am still running ones that have been in service for over a decade without issue.

[ken kimble]

How do the pulleys look? I'd remove the belt and run it....if it's still vibrating, look for something to do with the motor/motor mount. If not, check the arbor, bearings, blade, arbor nut, etc.

Thanks Scott. I took the blade off =no change. The motor is new and runs fine if no belt attached. I've tried tightening (temporarily) the friction screw on the mount but even that doesn't cut the vibration. The pulleys are machined cast iron
and seem to be ok. I took a link out of the belt since it seemed to have stretched. The blade free wheels beautifully with no belt on it- no side to side play.

Can these link belts suddenly become stiff?

[Andrew Hughes]

It's got to be a loose pulley,get a allen wrench in there and make sure they are tight.Sometimes there are two set screws stacked so you'll have to take one out to tighten the one that matters.
Good luck

[Ray Newman]

Are the pulleys coplanar?

[Lee Schierer]

If your saw is one that uses the weight of the motor to tension the belt, make sure that the hinge is free to rotate and that your new motor is installed in the proper position. Check the belt guard for a piece of debris or to insure it is not making contact with the belt when you raise the blade.

[Chris Hachet]

Also, going through and tightening everything can make a big difference in a lighter machine. I had lots of vibration in my 14 inch Jet band saw, it went away when I made sure everything in the saw was nice and tight.

Keep us posted, curious what the OP find wrong with the saw.

[Jim Mackell]

Have you checked to see if the key is still in place on the motor pulley? I had a similar issue years ago and it turned out the key hd fallen out and the pulley was just held in place by friction.

[glenn bradley]

I'm sensing a theme here . . . Since this was a sudden change, something related to the drive train seems most obvious and that is why we are all saying "pulleys". Has the saw locations changed? Are you now setting on an irregular part of the floor and the lightweight cabinet has tweaked under its own weight in order to make contact with the floor at all foot positions? The missing or moved pulley key is a good call . . . oops, we're back to thoroughly checking the pulleys again ;-)

One of the good things about link belts is that they are advertised as not having a memory; they don't get bumps. I find this to be true but, did have my antenna go up over something you said. I have never had to adjust for any stretch in my link belts. This includes a single belt drive on a 3HP jointer that has been in service since 2008. The fact that yours may have stretched makes me wonder what belts these are. I have used both Power Link and Accu Twist without issue. In fact I have used these in combination on the same belt without issue.

I'm just tossing stuff out there hoping something will help.

[ken kimble]

Guys
Sorry I've not been more prompt-life gets in the way of my hobby. I took the arbor pulley off, but found spline in place and tight allen screw. Same with the motor. I did "coplanarize" the pulleys with a long steel rule, but will do it again after I get pulleyes back on. The saw hasn't been moved more than an inch or two, but the base has been enclosed and is full of saw blades and accessories which weigh a lot. The "stretch" in the belt is probably an illusion on my part- I changed from a 1.5 hp (grizzly) to a Baldor 1hp which is smaller, so it didn't pull the motor against the belt until I removed the link. The belt was a "Power Link".

You guys are great. Even though I've tried a lot of what you suggest, it gives me a lot more confidence to hear you say it. Please don't stop.
Ken

[scott spencer]

Grabbing at straws here....was there by any chance a spring in the motor mount plate that fell out? Have you tried switching belts just to eliminate causes?

[Dick Brown]

My question is, can the motor move on it's pivot freely when you raise and lower the blade? I have refurbished a lot of the older Craftsmans and when I bought them a good share had the little 1/4" bolt, that is only there to keep the motor from falling over backwards when the belt is off and to dampen motor bounce, screwed down tight so the motor could not pivot with blade height changes. You can't believe the strain on things and noise when the blade is raised and the bolt was tightened with the blade down!

[Bruce Wrenn]

When I had my Craftsman saw and changed the motor, I had to reverse motor mounting plate so it was in a more horizontal position. Other wise, the motor was "climbing the belts."