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table saw rumbling
Hello,
It's been awhile since I've posted, but I often read and learn here and am thankful for all the thoughtful contributions.
I had read some archives around similar situations to what I'm facing, but thought a fresh thread wouldn't hurt too much.
I have an older Grizzly 1023 3hp cabinet table saw. I bought it used about a decade ago, and with minor tuning it has performed very well for all these years.
Last week I was doing a lot of work with a dado stack of blades installed when I started to hear a "rumbling" sound during operation (not just during breaking/stopping). I was able to finish the task at hand, and swapped back to a combo blade... which I then found was showing signs of vibrating and giving an unclean cut (where that has never been an issue previously).
With the saw unplugged, it is relatively difficult to rotate the blade by hand now. That was also never an issue before.
To date, I'll admit that my entire "maintenance regimen" for this tool has basically been to keep the top surface waxed. Never inspected or swapped belts or anything else.
My first thought is that the belts may need to be replaced, although I ran my fingers over them as my wife rotated the blade (saw unplugged) and didn't feel any obvious pits etc.
My second thought is that bearings may need to be replaced.
What do you think? Any tips on performing the steps of troubleshooting?
(I also sent a note to Grizzly to get their opinion)
Thanks!
Bob R.
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"Rumbling" combined with the blade deflection you mention could very well mean bearings or perhaps something else is loose with the arbor. I do think you need to "dive in" there, Bob, and hopefully rectify things quickly.
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Bob if you bought that saw used a decade ago, and going by the' bad cut with a combo blade' as well as' hard to turn the arbor by hand' comments it is time for new arbor bearings. Probably would not hurt to do the motor bearings as well. Then everything would be good for the next 20 years
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What everyone has said. Bearings are almost certainly the source of the vibration. In fact if it's causing a rough saw cut I am guessing if yo grab the arbor you will be able to move it radially. You have at least one bearing that's failing. It might be the drive end as well. Good luck.
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Release the belt and turn on the motor and see if the rumbling is still there. If not it is the arbor. I would replace all four bearings as long as you have the top off. I would say the grease has reached it's service life and has dried out.
Bill D
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In my heart of hearts, I figured this (bearings) was going to be the consensus. Looks like I'm going to get real familiar with the inner workings of the tool, so we'll get to add that to the shop skills list. Also a good time for me to re-tune the miter slots to blade etc. More soon as I give it a try
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Don’t jump to conclusions too quickly. You could have set in your belts which can cause similar symptoms. After you remove the belts and check the motor, spin the arbor by hand and see if you feel any crunching or so if they spin way too easily which means the bearings lost their lubrication.
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Like Bill said, remove the belts. From there you can manually turn the motor and arbor to feel for something not right. Chances are good it's the arbor bearings. I just replaced them on a PM 66 with Timken brand bearings. Probably was overkill for how much use I'll give the saw but they were less than $10 each so why not buy the best. Just remember if it is the bearigns you don't need to buy new ones from Grizzly. There's several very good brands to choose from.
As for taking the saw apart it's actually very simple. You'll want a second person unless you are strong as the cast iron top can be a little heavy. But it's a pretty straight forward job. You will need a gear or bearing puller or a shop press. When putting the bearings on the arbor always push on the same race (as in if you are putting the bearings on the arbor shaft push on the inner race). Also measure where your blade is at now (left to right) and try to get it exactly in the same spot. Otherwise your zero clearance insert will no longer be zero clearance.
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If you need new belts, make sure the new ones are the same diameter of each other. Some sets come mis-matched.
For bearings many restorers, myself included, go to Accurate Bearing. https://www.accuratebearing.com/
Best quality and service. I always dealt with Lynne.
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Make sure you measure the location of the bearing closest to the blade so you can place the new one in the same location. Otherwise the blade may not end up in the same location in the throat plate and any jig you have may not work with the new location.
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I had this same issue just a couple months ago. Mine may have been a little bit more obvious. Now my saw had been making a funny noise since I packed the cabinet full of saw dust, I did this milling down some dunage boards that I made a work-bench top out of. Anyway, one day the saw started making a horrific noise during a cut, shut it off asap, unplugged the machine and went to examine it. Blade would not turn by hand. My arbor bearings were shot! Over 10 years of service on them, guess I cannot complain. But I was also in the middle of a project and went into "nuclear melt-down" knowing that I would have to wait until Monday to order new ones, from Grizzly.
So Sunday I go out to the shop to tear things down, did a little research and learned that the bearings were a common automotive type bearing!! I had it up and running within hours after that.
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Note that pretty much all ball bearings are metric so measure them in metric. Do not try to measure in English units and convert. Some limited farm equipment may have semi custom inch bore bearings nothing. you will see in a post war woodshop.
Bill D
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I had a chance to get the belts off today. Saw unplugged through all of this except where noted.
First... I was able to loosen the motor mount bolt so that the belts had plenty of slack, and was able to slip them off the motor pulley easily. But, it was really a bugger to try to then remove the belts from the machine entirely as there is no space between the arbor pulley and what I think is called the "trunnion yoke". Interestingly, the downloaded Grizzly 1023 manual that I have (as i bought the saw used and it did not come with its original manual) does not show this item in the parts diagram... I do see this part mentioned in Delta Unisaw diagrams however. There are no identifying brand markers on the saw that I can find, so perhaps it's not a 1023 afterall? All other parts diagram items match exactly though... shrug. Anyways, I couldn't get the belts out without removing the top surface of the saw, and (read below) it seemed clear that removing the top was needed anyways... I'd like to figure out the answer for future instances, but for today, it was fine.
So, I went about removing the outfeed table, taking apart the portion of dust collection system that would be in my way, and had my wife help me remove the top. She wasn't quite strong enough and stumbled into a blast gate for my nearby jointer which I will now have to re-build. Damn, but no one was hurt (I'll use my neighbor for help putting the top back on). Once we got the table leaned on the floor I could move it around by myself and it's presently leaning against the wall, out of the way.
Removing the top enabled me to get the belts off. They looked fine. One had a very tiny crack in one spot, but all three seemed to me to be identical in size and shape, and overall appeared like-new. I'll replace them anyways since I'm doing surgery, but I don't think belts were the problem.
With the belts removed, I hand-turned the arbor which felt crunchy in the forward direction, and literally wouldn't turn in the backwards direction. If I tried to give it a spin to see how long it would go, it would go about 1/2 of one rotation. I also hand turned the motor which rotated easily and smoothly, and the same spin test resulted in about 10 revolutions. I momentarily plugged the saw back in and ran the motor for a few seconds - nearly silent during its operation.
So, I think it's time to pull the arbor apart per the videos I've found (one from Grizzly for this exact model, another very similar for Unisaw).
Before I do, it's a sawdust desert inside that cabinet right now, so I'm going to clean it up and attempt to install some sort of chute that will guide dust towards my dust intake pipe more efficiently.
Wish me luck!
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This should help since the 12/14 is just a overgrown unisaw.
Bil lD.
http://wiki.vintagemachinery.org/1214ArborBearings.ashx
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Not going so smoothly so far...
I was able to get (what I'll call) the arbor assembly pulled out of the saw following steps like found around the 4:15 mark of this Unisaw video. (He calls this assembly the "arbor bracket")
The next steps in that video include removing the nut from the end of the assembly, and then a couple set screws that hold the arbor pulley in place. Whether you look at a Unisaw or Grizzly 1023 parts diagram, these parts and steps are very similar.
Here's the issue... The arbor pulley in my case doesn't have any set screws. There's one "pitted" area that I thought could be a diagonally-oriented set screw, but the mechanic next door and I looked at it really closely and think it's really just a pit.
Anyone ever seen an arbor pulley that doesn't have set screws? I don't want to start pounding on it if I'm missing something...