Table saw shake when stopping

Hey Julio,
Don't know the Hitachi, but no other saw I have ever had shook when it slowed down. I would definitely do a little investigating before I put a load on the saw.

Your idea on the belt is the most likely cause, I would guess. Check the manual and see how tight its supposed to be.

While you are under the hood, check the arbor to see if there is any play - could be a bad set of bearings.

Also make sure there is nothing (like packing material:rolleyes: ) interfering with the movement of the moving parts down there.

I'm sure the guys who know what they are talking about will have lots to add.
Take your time and get it right, especially before you build any jigs for it.:thumb:
 
julio, it could very well be belt set? try running the saw (after checking what jesse pointed out) for a few 5-10 min in order to warm the belts up....see if that helps? tod
 
Tod may have it nailed. If not belt set it's going to be the belt vibration. If you can watch the belt when you shut it down. I bet your going to see some strange gyrations from it.

If I am not mistaken to tight a belt can cause that too. Like a vibrating guitar string.

Jeff
Mr. Wizard wannaB :eek:
 
I do not know what is to be expected of the Hitachi but I have a 3hp Uni and it jumps a bit on startup and when I shut it down, just before it comes to a complete stop, it gives a bit of a shutter. I have been using it daily for the last three or four days so it should not be belt set and the tension is fine. I never really notice it untill the subject comes up. Unless it is a real big vibration I don't think that I would worry about it if you check the belt tension and everything esle checks out fine. I think that it is just the nature of the beast on some saws.

Of course an ''uncomfortable shake'' might be another matter depending on how bad it is. Another thing is that an "uncomfortable shake" might be a "shutter" to me or vise versa.
 
I fought with my PM66 awhile back and learned a whole lot more than I wanted.

Make sure your pullies are aligned and the set screws are tight.

Even if your arbor assembly feels tight, it probably has some set screws as well, so make sure they are tight (DAMHIKT).

Make sure your belt(s) are tight as others have suggested. If it still does it after all this, I would probably take the belt off and inspect it to see if it has premature cracks or is defective.
 
Of course an ''uncomfortable shake'' might be another matter depending on how bad it is. Another thing is that an "uncomfortable shake" might be a "shutter" to me or vise versa.

That's right Alan, I think it's similar to what you have, it's not alarming as in shaking uncontrolably, just that it makes things rattle instead of humming to a stop.I can see tightning the rip fence guide rails t-bolts every so often from being shaken lose.
It doesnt shake while running, it's smooth and even. Just as the blade is slowing down at say 1/4 speed till it stops. Something I didnt expect.
 
I fought with my PM66 awhile back and learned a whole lot more than I wanted.

Make sure your pullies are aligned and the set screws are tight.

Even if your arbor assembly feels tight, it probably has some set screws as well, so make sure they are tight (DAMHIKT).

Make sure your belt(s) are tight as others have suggested. If it still does it after all this, I would probably take the belt off and inspect it to see if it has premature cracks or is defective.

I think I will do that, Travis. No harm in looking under the hood.
 
My tupence: Is the blade properly secured? Have you removed the blade to check for flatness? If it's bent and wobbly that might not show up at high speed. But, like one of my grinders, could almost bring the house off it's moorings during slow-down time.
 
I recall a thread on one of these forums a while back that discussed this. It was explained therin that a voltage discharge from the motor or some such was a common cause of the shudder on shut-down. Whoever the expert was on this thread said it was typical of a lot of electric motors and nothing to worry about. I tend to believe this; I've had my JET contractor saw for 14 year now, its has always shuddered on shutdown, but has always been very accurate, with never a problem of any kind,in fact it works so well I can't justify in my mind moving up to a cabinet saw. FWIW my dust collector and DJ20 jointers' motors' both shudder on shutdown as well. I prsonally dont find it a cause for concern. Barry
 
I don't think it is the motor. Try shutting it down with out the belt on. It probable won't shake. It is the same thing as a car with a tire out of balance. At a certain speed of decleration the cars wheel will start shaking. If it bothers you, I would try a link belt and machined pulleys.
 
My tupence: Is the blade properly secured? Have you removed the blade to check for flatness? If it's bent and wobbly that might not show up at high speed. But, like one of my grinders, could almost bring the house off it's moorings during slow-down time.

Excellent point Frank, Ive had that happen also but it didn't occur to me here.
 
Julio,
My Sears Craftsman 22124 does the same thing right before coming to a complete stop. I am on my 2nd motor and the 1st one did the same thing. I don't think that the belt is loose since on 22124 the weight of the motor keeps the belt tight. I doubt it's the blade either since it shakes with stock and WWII blades.
 
I contacted Hitachi and they communicated to me that what was happening was not normal and that I should take the saw to the nearest service center, which is not terribly far but I would still need to take the saw and who knows how long it would take to get it back...all in all it's a hassle. I wish they would have given me the instructions on how to eliminate the shake but I suppose liability issues prohibit that.
 
I contacted Hitachi and they communicated to me that what was happening was not normal and that I should take the saw to the nearest service center, which is not terribly far but I would still need to take the saw and who knows how long it would take to get it back...all in all it's a hassle. I wish they would have given me the instructions on how to eliminate the shake but I suppose liability issues prohibit that.

At least they are concerned about a possible problem and want to give good customer service. Better than a blow-off and serious problems down the line.
 
OK, here goes. BIL while in my shop a few years back noticed that I had the same problem with my old Cman. He kinda laughed, unpluged the saw, lined up the pulleys and tightened up a set screw that was letting the arbor pully move. No more vibration on slowing down. Don't really know if this is your problem or not, but his explanation was that while it was slowing down and the pulleys were not in alignment the belt was trying to climb one or the other pulleys. Guess that I have to believe him, as it never shook again.
Hope it helps,
Chuck
 
Well, the blade is nice and flat and it's easy enough to open the back panel and see if the pulleys are lined up and tight.

But you are right Frank, at least they replied and it seemed as if my question went up the ladder as my reply had the e-mail chain from the person who received it up to a technician with comments back and forth till they sent me the response.

I'll check the pulleys, if all seems well there I will take the saw to one of their service centers.
 
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