New Jointer Vibration, G 0490 Griz - Woodworking Talk

Ed'sGarage · 01-12-2010, 03:39 PM

I rcvd my new jointer last week and now have it fully assmbled. Unfortunately, it has a massive vibration. I have spoke with Grizzly Tech service and they are researching this. Hopefully they'll have answer in a few days. In the meantime, I figured I'd tap into the collective experience of this forum for some help; hopefully.

Jointer runs w/o any vibration after start up. The vibration occurs in a small part at start up but really makes a racket just before the jointer comes to a stop. It appears(just a guess) that the vibration is a function of the drive belt. The motor pulley and the cutter head pully appear to be lined up well. In addition, the set up instructions ask for a 1/4 inch deflection on the belt after all is tightened up. Because of the way the motor is mounted on the machine, I can't get the belt tension deflection under 3/4 inch. I have tried having a friend help, using a 2 x 4 for leverage and other things to get the belt tighter, but haven't had any luck getting it tighter. I'm not sure this is the problem, but I'd sure start with this.

If anyone has an idea how to get this tighter or another problem that would contribute to this condition, I'd appreciate the input. I really don't feel the jointer should be run with this type of vibration; it'll just manifest itself in things falling apart, or damaging themselves eventually.
Ed

woodnthings · 01-12-2010, 05:50 PM

It's a harmonic vibration since it goes away. The motor has slots on the base and you're maxed out right? No answer other than a shorter belt.
It's a cheap enough thing to try while Grizzly scratches their collective heads...The size should be printed on the belt 4LXX something like that or a MM size. Automotive belts have a different angle to mate with the pulleys. You need a fractional hp motor type belt hence the 4LXX designation. Graingers or Tractor Supply may have one. Good luck, you can always make a random orbit sander out of it...

bill

Ed'sGarage · 01-12-2010, 06:40 PM

Woodnthings: There is more room in the slots for more tension, I just haven't figured out how to PUT more tension. Again, I tend to agree that it's probably that the belt is not tight enough, but I have run out of ways to get more tension. There is still plenty of room for more extension in the slots of the motor. I was thinking of trying to rig some type of auto jack in between the motor and the frame to get the desired tension. I wish they had put belt tensioner's on their machinery. That would make this a cake walk. I used to be in the printing business and most machines came with a belt tensioner, much like that on a car. W/o that it's like a juggling act trying to get the tension on an already loose motor and then trying to get it tight before the tension goes by-by.

If you know any secrets to that, let me know.
Ed

woodnthings · 01-12-2010, 07:55 PM

as well as clamps. A wooden block trimmed to the right length braced against the cabinet might work. A turnbuckle anchored to the cabinet with eye bolts might work. Anchor one corner loosely, and rotate the motor into the correct position.

bill

mickit · 01-12-2010, 08:28 PM

careful about belt tension...too much makes for early bearing failure or bent shafts,.
1/64" deflection per inch of pulley separation(center to center) is the ROT I use.
Mick

Ed'sGarage · 01-13-2010, 10:59 AM

Mick, 1/64 inch works out to just about 1/4 inch deflection for the distance between the two pulleys, so that seems to be about right.

Bill - given the way the motor sits in the frame, seems like the wooden block might be a good way to try. I'll try that this afternoon and let you know.

Thanks guys.

Ed

firehawkmph · 01-13-2010, 09:55 PM

Ed,
Do yourself a favor and go get a poly link belt. When I brought home my jet jointer last year, it was vibrating a little. Jet sent me another belt right away. It also vibrated. Nothing wrong with the machine. When you fired it up without the belt there was no vibrations. You could see where the belt was seamed it wasn't true. The owner of the woodcraft store where I bought it from gave me a link belt, vibration gone. I have used them on other power tools with good results.
Mike Hawkins

Ed'sGarage · 01-14-2010, 10:35 AM

I got a call from the Grizzly tech department yesterday. They said that some(got that? some?) of the motors on the G 0490 have an electro-mechanical problem that causes the motor to generate electric after it is powered down and the rpm's are returning to zero, causing the offending shudder(vibration). They said that although they didn't think this would harm anything(I think it will) that they would be willing to send me a new motor. Needless the say, the gracious person that I am, I accepted the new motor w/o any further persuasion. They did however say, that they weren't sure that a new motor would correct the problem, but they thought it would. The tech rep also indicated that he did not think that the belt tension had anything to do with this shudder. BTW, in deference to Grizzly, I was able to hold the phone to the motor to let them hear exactly what the motor assembly was doing. Also, note that they were more than accomodating and got back to me exactly when they said they would. I am anticipating the delivery of the new motor and hoping that it will correct the shudder. I'll let everyone know next week.