Do you consider this normal vibration?

[Steven Hsieh]

http://www.youtube.com/watch?v=k6NjAT4ZOy4 (http://www.youtube.com/watch?v=Q93OsV7vORg)

http://www.youtube.com/watch?v=jlRvwW9D7XA

http://www.youtube.com/watch?v=GZT9E38odwQ

[Stephen Cherry]

no, that's not close to being normal. It looks like something isn't round, as well as not balanced.

[Gerry Grzadzinski]

Looks like something loose, like the whole top of the saw??

[Sean Troy]

Loose pulley wheel or the throat support isn't tightened down correctly.

[Steven Hsieh]

Obviously it the failed the nickle test.

First day I got this bandsaw, it was vibration free.
Up until now, when I did some experiments had to remove the v-belt. Put everything back to together. Turned it on and Start doing this.

Grizzly sent me a new v-belt, much better than before, but still some vibration.

[Steven Hsieh]

Loose pulley wheel or the throat support isn't tightened down correctly.

The throat is tight, I never touched it.

The grizzly manual says at least have 3/4 deflection.
This is what it looks like.

http://www.youtube.com/watch?v=Gb5mFuZ5640


So i tried using 1/2 deflection.
Same results..

[Matt Logana]

I looked closely, and noticed this:

The blade isnt within the guides..... It may be a video mis interpretation, but from viewing it on 400% it appears that way.

Else you might try some magnets on the upper wheel... try to balance it...

[Stephen Cherry]

The first thing I would do is run it without a blade-- if it still vibrates you know it is in the bottom wheel.

Do the wheels look wobbly when you spin them by hand?

[glenn bradley]

I also noticed that the guides were moved back but, that will not cause or negate that vibration. Since it didn't do it before and you mention removing the belt to perform some action, I wonder what that action was(?). Whatever it was that amount of vibration would keep me from using the saw, at all, until I had it fixed. The amount that the head moves in relation to the table looks like something almost has to be loose; can the cast iron really flex that much? Please keep us informed and do not use that saw until you find the culprit.

P.s. Fix that belt ;-)

[Tom Esh]

Obviously it the failed the nickle test.

First day I got this bandsaw, it was vibration free.
Up until now, when I did some experiments had to remove the v-belt. Put everything back to together. Turned it on and Start doing this.

Grizzly sent me a new v-belt, much better than before, but still some vibration.

Single V belt, or poly-V (wider flater belt with multiple V's)?
With the poly-V, it's sometimes difficult to tell if it's actually fully seated properly on the pullys (all Vs in their grooves), especially when it's hidden behind the lower wheel.

[Keith Westfall]

Even though you say you have 3/4 ' deflection, that belt looks loose. It is vibrating back and forth quite a bit, and doesn't appear to pull tight around the bottom pulley.

If having the belt off is all you did, I would pursue that further. Tighten it a bit and see what happens. I don't think it should whip as much as it is doing...

[Tom McMahon]

In the video of the belt turning the belt does not look near tight enough to me. There is a difference between 3/4" deflection and 3/4" loose.

Keith's post appeared as I was writing what he said.

[Tom Esh]

:eek: Just saw that last video. The belt definitely looks ~way~ loose. 3/4" deflection seems like too much. Check the manual again. 1/4" would be more like it - and that's generally with moderate (5 - 10 lbs) finger pressure.

[Steven Hsieh]

Seriously I think the manual has a typo. Even the grizzly tech reccomends a 3/4 deflection in the email. He said it prevents stretching and increase the life of the belt.

I have sent the videos to him to see what his response is
I'll let you guys know in the morning

[Michael Arruda]

PLEASE check and make sure that the arm is bolted together snugly. In watching that last video, your belt is definately too loose. That would not cause the vibration you are experiencing though. I've seen and felt far worse with no problem but either jumping the pulley or squealing and stalling. Also, in the last video, there doesn't seem to be much vibration in the drive side (lower half) of the saw.

I've seen steel framed saws bounce like that, but not CI. I know pacific rim CI is, well, crap compared to the iron of yesteryear, but I can't see it being THAT bad. It really looks like something is loose- CI isn't that elastic, in my experience. Also, consider that if it is that elastic, it won't be for long. CI doesn't like flexing repeatedly, and I don't want to read a story of how you had a great month in the hospital when your saw cracked in half and attacked you. Be careful until you know what's going on.

In the third video, it seems the top of the saw dips slowly at the very end of the video, in time with the wheels spinning slower. This would be indicative to me of a wheel out of round. It could be a bent pulley as well.

-Michael

[Stephen Cherry]

Something stuck to the top wheel?

Can you post videos of the running surfaces (the blade running on the rubber part of the wheel) of each of the wheels? It's running as though something is stuck onto the wheel causing the tension to increase either once per wheel revolution.

[Perry Holbrook]

Obviously it the failed the nickle test.

First day I got this bandsaw, it was vibration free.
Up until now, when I did some experiments had to remove the v-belt. Put everything back to together. Turned it on and Start doing this.

Grizzly sent me a new v-belt, much better than before, but still some vibration.

If the saw was fine before and not fine after you did your experiments, chances are pretty good that you caused it somehow. I dare say most of us have done something like this. When I've done this, usually if I repeat what I attempted the first time, I'll find the problem. Worth a try.

Would you care to tell us what your experiments were?

BTW, the belt is too loose, it shouldn't slip when you start, which you can hear on your video.

Perry

[Steven Hsieh]

Because The wheel was tilted at the left little, not much.
I thought it was not bolted correctly..
Folks at lumber jock had even problem tracking their blades.

So i removed the wheel and V-belt.

It was fine, it was cast iron frame is not flat.

Put everything back together and started the machine.
It started doing this.

I am guessing I installed the wheel improperly.
Or either the V-belt.

When I get back from the gym ill record more.

[Ray Newman]

My SWAG (Scientific Wild Arsed Guess):

-- Agree that the belt appears to be too loose.

-- In an earlier post, you said you removed the "wheel".

By "wheel" do mean upper and lower blade wheels or the pulleys? When you re-installed the the "wheel" (or pulley), did you check that it was still coplanar with the other?

[Lee Schierer]

Your belt is way too loose. If you tighten the tension, the problem will go away. As you start your saw you can hear the belt slipping. The belt should not flutter when it is running. The flutter indicates it is loose and will result in poor cutting performance as well.

You should be just able to deflect the belt at the center of the span between the pullies about 1/4" with firm finger pressure.

[Steven Hsieh]

Here's is Grizzly tech response



Some basic troubleshooting of your G0555 14” Bandsaw should be performed. If the issue is vibration with the blade installed then the blade should be removed to see if they vibration stops. If the vibration is reduced but still evident then the drive belt should be removed from the pulleys. If the vibration is still evident but reduced the motor or the motor pulley could cause the issue. The hardware attaching the pulley to the motor shaft should be checked. This includes the key in the keyway of the pulley and the setscrew through the collar. If the setscrew is loose it will allow the pulley to move on the motor shaft. If the pulley moves on the motor shaft the key will wear and eventually break or fall out of its slot causing damage to the motor shaft. If after checking the pulley and all is well and the physical condition of the drive belt is good you can reinstall the belt and tension it properly.

The wheel only installs on the wheel shaft one way and the nut at the center needs to be snug. Once the nut has been tightened the wheel can be gently spun by hand to see if it settles at a heavy spot. If the same spot on the bottom of the wheel comes to rest in the exact same place all the time the wheel may be out of balance and needs to be rebalanced or replaced. This same test can be performed on the upper wheel. Next the condition of the tires that are stretched around the wheel should be inspected. If there are any high or bumpy spots the blade will ride on these and will cause excessive vibration. The final check is to make sure the blade tracks at the center of the wheels and possibly try two or more blades to verify this as not all blades are made equally.

Finally, if the vibration is heard more than seeing physical movement of the saw the sound may be caused by the sheet metal covers and shrouds placed around the blade wheels. Loose hardware such as hinge screws, upper and lower guard covers stud and latching hardware and stand carriage bolts should be looked over for tightness.

Unfortunately, I was unable to view the video links you sent. Our Internet access and server protocols prevent me from accessing peer sharing sites such as www.youtube.com (http://www.youtube.com/).

[Myk Rian]

OK, it looks to me;

The belt is too loose. Way loose.

The vibration begins when the start contacts make on wind-down. That is when the capacitor kicks in to slow the motor down, thus the vibration.

[Steven Hsieh]

Tension at 1/4
http://www.youtube.com/watch?v=0ZM9DGGGEsA


This is the nickle test with 1/4 tension, no blade.
Notice the nickel rolls a bit but doesn't fall.
Okay ignore the falling part, i press the off too hard.:D
http://www.youtube.com/watch?v=IB_-pAsNk0s



Top wheel with open cover
http://www.youtube.com/watch?v=XVdsjoMDVYI

Table vibration
http://www.youtube.com/watch?v=bQXklB6VEmU

[Gerry Grzadzinski]

Did you take the tire off the wheel? In the video it looks crooked? That could definitely be the problem.

[Stephen Cherry]

It looks like something with the top wheel or tire causing the blade tension to be increasing and decreasing once per revolution.

[Steven Hsieh]

Guys Guys I have very good news.

I removed the lower wheel and belt and start over. I removed the lower wheel, V-belt, bolts. Started over.
Lubricated the bolts, wheel.

Turned it on with a 1/2 blade.

The top wheel does not dip/shake that much than before.
But the table vibrates still.

I'll post a video of it tomorrow.

[Lee Schierer]

Guys Guys I have very good news.

I removed the lower wheel and belt and start over. I removed the lower wheel, V-belt, bolts. Started over.
Lubricated the bolts, wheel.

Turned it on with a 1/2 blade.

The top wheel does not dip/shake that much than before.
But the table vibrates still.

I'll post a video of it tomorrow.

That's great, but lubrication isn't your problem, a loose belt is....

Try resawing a piece of anything 2-3 feet long that is near the full capacity of your blade guide height and you will soon smell rubber if the blade doesn't stall first.

[Chip Lindley]

First day I got this bandsaw, it was vibration free.
Up until now, when I did some experiments had to remove the v-belt. Put everything back to together. Turned it on and Start doing this....


I cannot resist pointing out the obvious: Whatever experiment you did, you did Not need to do. DON'T MESS with SUCCESS! Retrace your steps and put the saw back together as it was originally. The concept of, "If It Ain't Broke, Don't Fix It" is alive and well.

Try a PowerTwist link belt on the machine. One worked wonders for my ol' Delta 14".

[Terry Beadle]

I vote with the blade not being in the guides properly. We can't see the bottom guides but the blade is definitely out of the upper guide bearings.

[Cliff Rohrabacher]

looks a little wrong to me, crazyanime guy

[Van Huskey]

Other than the belt my first inclination would be the pulleys.

[John McClanahan]

I have been watching this thread hoping someone will find the answer. i have a new style Craftsman 12" steel frame BS that has the same table shake. I have a crank adjuster for the belt that everyone says is too loose, though mine is a multi-groove flat type belt. Belt tightness has no effect on the amount of table shake for me. Nothing stuck to the band wheels and guide bearings properly adjusted. Smoothes out when up to speed.

John

[Bob Wingard]

The whole shaking issue might be a harmonic that just "happens" at a certain speed. It probably does it on the way UP as well as when coasting DOWN .. it just goes through that speed too fast to even notice. While it is not a desirable phenomenon, if it's not doing it at normal operating speed, you might be better off just ignoring it.

Going to heavier cast iron sheaves might help just because it changes the weight on the armature. It's worth a try if you can just borrow a set to see what the effect might be.



Found the following in an Electric Motor Troubleshooting Manual .. .. ..

Axial movement and the resulting presence of a third harmonic of the running speed is another indication of motor instability or imbalance. The third harmonic is present whenever there is axial thrusting of a rotating element.

One last thing I might mention .. .. is the AXIS of the MOTOR parallel to the AXIS of the LOWER WHEEL ?? If not, the motor arbor can pull against it's bearings which "side loads" them in a manner they aren't intended to handle. Kinda just the opposite of using a drill press as a spindle sander .. in this case, the bearings are only there to allow the arbor to spin .. but side loading applys axial pressure.

[Phil Thien]

Bandsaw shudder. I've seen it on a lot of saws.

[Bob Wingard]

The motor armature should have a small dimple in the center of each end of that shaft .. .. .. when you power down the saw .. carefully push a center punch or nail set into one end, and let it run down to a stop, maintaining the pressure. Do this in both directions, and see if the shudder goes away. If the armature has "end shake" this will load the bearings in one direction .. then the other to take up the slop. Most armatures have a "wavy washer" to apply light pressure, keeping everything centered, but if it has collapsed or if the armature is not parallel to the lower wheel shaft, it will do this.