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Tablesaw blade wobble... but slow?

435 views 28 replies 11 participants last post by  FrankC  
#1 ·
Hello All,

I've mentioned in prior posts that I'm making a new battlefield chessboard utilizing some beautiful Black Walnut I inherited. Well, I finally got some Hard Maple for the light colored spaces and began work on the board. The very first step of course is to cut the alternating strips. Fortunately, I began with the maple in case something went wrong. The pieces I've cut so far might be salvagable, but I'm not really sure where to begin with this issue.

The issue is that there's some kind of slow wobble in the blade causing terrible blade marks on the cut. The blade has maybe 20 minutes of use on it and was cleaned prior to this cut, so the issue should not be the blade. I did put this blade on right before the cut and I know one factor to be suspicious of is over-tightening the arbor nut so I'm pretty positive I did not do that. I also don't think I under-tightened it because the nut is still tight after the cuts. I also know that the fence needs to be parallel to the blade so I double checked that and found that the difference between the front and the back of the blade (using the same tooth) is .004 inches. Not perfect, but definitely not bad enough to cause this kind of issue.

I'm not sure how best to describe the issue so I recorded a video where you can see I'm feeding at a pretty consistent rate and am using a featherboard to ensure constant pressure against the fence. I've also included a marked up picture to highlight the cut direction which I think is a clear indicator that the blade is wobbling when it makes that noise in the video.

Please let me know your thoughts on this, a perfect cut on a bandsaw isn't critical, but it is on a tablesaw, and this issue seems downright scary.

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#2 ·
Watch the blade as you shut it off and see if it wobbles when real slow. The blade may be warped. If it's a thin kerf blade that is a real possibility. Sometimes when a blade gets hot it will follow the soft grain of the wood and bend and if you turn the blade off before it cools it will stay warped. A saw sharpening shop can fix this but for now you need a new blade.
 
#3 ·
Watching the blade while it's running and while it slows to a stop shows that the blade is perfect. I see zero wobble at all which. If not for my issues with the Skil tablesaw I had, I might think maybe it was just beyond my vision to see, but that saw definitely had a wobble at one point, so I'm pretty confident this one doesn't.

What you said about the blade softening and following the soft grain of the wood is interesting, maybe that's happening but it unwarps before it cools? I'll put on the other blade I have which is a full kerf blade and see if the issue happens with it.
 
#5 ·
I was feeding it slowly partially because I was holding my cell with one hand to record and partially because I wasn't sure if the feed rate was the issue. The prior cut was a quicker feed rate and had the same issue. I believe the intermittent chip spitting is a result of the occasional wobble. It seems like it wobbles a few rotations out of a thousand (completely random numbers, but you get the idea). I think the chips being spit out is when the backside of the blade cuts through the wood on the way up.

Going to head back out and try a different blade now.
 
#9 ·
The arbor faces are clean. I had just changed the blade immediately before these cuts and made sure they were free of debris/junk.

I haven’t checked the arbor for runout, but now that the arbor lock isn’t working, I think I need intervention from the manufacturer before continuing to troubleshoot this issue. That being said, if there were some really bad runout somewhere, I would expect a constant wobble rather than a wobble every few seconds when under pressure.
 
#10 ·
There's a few things that can cause this;

The first thing I'd do is try another blade... and probably a different style/grind. For instance,if you try the same blade albeit a new one,that would/should indicate a problem with the original.

If however,there's an issue with the style of blade,the new one could exhibit the same result. So I'd try a different style/grind/tooth count.

You have to answer this for yourself; do you "just" want to get your pieces cut? Or do you want to dive into the deeper end of things and try to understand machine dynamics? And please,don't answer that for me or anyone else.


Good luck with your project.
 
#12 ·
I would suggest putting a dial indicator on the bed and rotating the blade. If there appears to be wobble, try another blade or a thicker plate such as a blade stabilizer. If the situation corrects itself, it is the blade. If it does not it is likely your arbor. When cutting hard dense lumber such as hard maple I suggest you keep the blade high and use a faster feed rate. A slow feed rate and low blade can also heat a blade up and cause it to deflect, especially a thin kerf blade. When I send my blades back to Forrest for sharpening they always check the plate and flatten it if necessary. Can even happen with high quality blades.
 
#13 ·
It would help to have a picture , brand, style of the blade you are using. To me this is harmonic vibration. It LOOKS TO ME that as the blade "speeds up" to max RPM possibly from a light load on the cut, it vibrates , strikes the work , such that it slows the blade and reduces the vibration. Then when the blade speeds back up the vibration returns and the cycle repeates. Why this doesn,t happen with no work on the blade simply because the RPM unloaded passes through the RPM at which the blade may be reacting to, finding the harmonic vibration frequency. My guess is most of it is the blade and some of it is your feed rate( at least in the one hand video demonstration). If you are looking to get a jointed edge from the table saw cut you are possibly chasing a ghost. For the game board you are working on you will need every joint to be pretty darn perfect . That suggests the employmnt of a jointer or drum sander. Lastly the first thing I would try is a quality brand combination blade. If you are using a thin kerf or worse yet a hollow ground planer blade you will continue to get what you demonstrate in the video.
calabrese55
 
#16 ·
Along this line of thinking;

Gullets filling up,can only take so much,blade starts vibrating... semi violent. Swarf being evac'd out the top,where just before the dust was going down. And this can be a secondary,or "minor" effect... not the main culprit.
 
#17 ·
The tablesaw is a Laguna Fusion F3 with a 36" fence.
It sounds like I'll definitely want to try a full kerf blade which I have, so once the arbor lock issue is addressed, I'll give that a shot (assuming Laguna doesn't think it's something else).
For these cuts, I do have the gullets fully exposed. I would try a higher blade height just to see if that helps, but I think if the blade ends up being the issue, I'll just ditch the idea of a thin kerf blade all together (at least for cutting thick stock and important cuts).
Regarding the feed rate, it does happen at a higher feed rate. I don't remember for sure, but I think it happened quicker with a higher feed rate.

I have a concern that I'm not sure is a valid concern. I changed the blade right before these cuts and I don't specifically remember confirming that the arbor lock released when I was done tightening the nut. Does anyone know if saws are smart enough to not run if that lock is still engaged, or is it possible I turned on the saw and sheered the lock off? This would obviously cause the failing lock issue, but I'm thinking the force required to sheer the lock loosened a bolt somewhere as well so maybe when pressure is applied to the blade, the arbor or motor or something is allowed to shift before it snaps back into place.
 
#18 ·
GREAT NEWS!
I'm just a stupid stupid idiot. The arbor/blade lock wasn't engaging because I didn't have the blade raised up all the way. I was a bit short on sleep yesterday, but apparently it affected me more than I realized. I feel really stupid now, but hopefully this post helps out someone in the future.

Now that I'm able to change the blade without worrying that I destroyed the saw, I swapped out the blade for a full kerf blade and did another cut. This cut wasn't super clean because my full kerf blade has a bit more use on it, but it didn't do the weird wobble thing. There were a few possible explanations suggested as to why the thin kerf blade could be the issue, and my guess would be that it followed the softer grain of the wood since I think the frequency was tied to my feed rate. However, I'm satisfied just knowing that the blade is the issue. I think I'm going to invest in a good full kerf combination blade as recommended by @calabrese55. Stumpy Nubs on YouTube is always recommending Ridge Carbide. I always thought it was kind of pricy at $150, but I just checked Forrest and a 40 tooth 10" from them is $235 so that makes Ridge Carbide seem much more reasonable.
 
#19 ·
I dunno, I'd be thinking the blade wasn't tightened down since it didn't lock, no? I had the same think happen to me with my Flex saw - my excuse was ignorance, not stupidity. There is a difference, you know. :ROFLMAO: :ROFLMAO:

You don't say what model this is, but I would consult the manual about using full kerf blades. If this saw is 1.4HP or less, you will see a benefit using thin kerf blades, particularly when ripping. With the use of blade stabilizing washers, it shouldn't flex enough to be an issue. Also, check the riving knife that came with the saw - that will be a clue as to what they want you do use.
 
#20 ·
The model was mentioned in post #17. It's a 3HP saw, but I did originally start using the thin kerf blades because my old Skil tablesaw would struggle cutting through 8/4 stock. As for the not locking issue, I was referring to the lock that prevents the blade from spinning so you can tighten/loosen the nut that holds the blade in place.
 
#21 ·
@SomeDudeOnline while looking for information on your problem I got sidetracked and just now posted and I missed your post 17 but since I already wrote it up you're still going to get it.
blade stop note blade must be all the way up
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red tab
table top removed Laguna Fusion F3 Table Sawthe red tab when pressed to the right it will lock the blade.

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uses a lock pin
can Not find a better picture of how it engages.

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this belt is not easy to get to and adjust.
this maybe your speed problem.

table saw cleaning F3 the user said that poor dust collection is a real problem it doesn't create enough velocity to remove all the sawdust that ends up inside the chamber the table saw box itself.

Below is the PDF that I found based on a fusion 3.

Also found written comments on Reddit where his lock was not working and he ended up having to clean the entire assembly with the blade off and found it it wasn't engaging in the Locking pin cuz it was packed full of Sawdust.

Good luck on your challenge with your table saw
 

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#23 ·
@SomeDudeOnline
Also included the thing about the belt because it's a pain in the neck to adjust correctly loosening up to two bolts in the motor getting into turn a lot of complaints about that.
Causing the belt to slip a lot so you get that spinning up and down effect.
Indirectly there was a YouTube video about complaining about Laguna not replacing the motor and timely basis but I also found that the ears on the motor or easily broken if only trying to loosen one and think it's going to Pivot without the other one being a little bit loose to allow it to Pivot so be aware of that.

Cause used to use av-belt and based on tracking down the one that was listening to parts list in the manual they turn into that orange belt which that type of GrooVe belt usually holds up really well at least in the environment I use those belts in at work but not a dirty environment I eat full sawdust.

Also I hope you're using good dust collection because otherwise the bottom of the cabinet turns into a large dust chamber to store Dust where you don't need to be kept at I think I included a link where one guy described the problems with insufficient dust air volume to keep it clean.

Also on another woodworking form lumberjacks had mentioned a couple of places of on the V belt type of having problems with thin curved blades leaving a lot of marks due to wobble and also insufficient belt tension causing the blade to be vibrated from the belt bouncing around but you've got the orange belt so I'm not sure how that plays into the conversation.

Good luck.
 
#24 ·
SDO, thanks for getting back to the group with what you found.
Glad you are on the right track !!

But gotta correct you on one point. Your not an stupid, stupid idiot as you claim.
No need to be so hard on yourself.

I was not aware that the Laguna has a arbor lock when raised all the way up to assist with blade changes.
That's a cool feature. Does the group know if other saw brands have that?

I have a older Craftsman cast iron top, and Steel City Granite top, and neither of those have that feature.
Seems like it would be common place?
 
#26 ·
I have a older Craftsman cast iron top, and Steel City Granite top, and neither of those have that feature.
Seems like it would be common place?
Older saws came with two wrenches, one for the arbor shaft the other for the nut.
Cheaper to make them that way back when.
When removing the blade with only the nut wrench, jam a scrap of wood under the teeth so it holds the blade in place.
 
#25 ·
Glad you cleaned the blade. MIght want to check the axle washer surfaces and arbor nut as well. (We'll assume the saw and fence are set up true/square/plumb to the arbor.)

And, or course, swap blades and re-test both on scrap material and make sure the workpiece is jointed and square.