Weird tablesaw cut problem

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Forum topic by Woodknack posted 04-03-2013 04:52 PM 2128 views 0 times favorited 42 replies Add to Favorites Watch
View Woodknack's profile


11479 posts in 2345 days

04-03-2013 04:52 PM

Topic tags/keywords: delta tablesaw troubleshooting question bad cut

My 15 year old Delta contractor has developed a strange problem. Every so often when cutting through the middle of a board the blade will give a little wobble. It happens at regular intervals, maybe every 3 seconds. It’s very obvious on my full kerf rip blade and it may be happening on my thin kerf combo blade but it’s hard to tell.

If it is the blade, wouldn’t it happen almost constantly? Unfortunately I don’t have a dial indicator to check the blade but since it only happens once out of every couple hundred rotations it might be impossible to measure.

It’s hard to describe and too subtle to photograph but you can hear it. Here is an exaggerated drawing to show what I mean. It might happen 3 times on a 4 foot cut.

-- Rick M,

42 replies so far

View Hammerthumb's profile


2836 posts in 1940 days

#1 posted 04-03-2013 05:11 PM

Check your belts. Might need replacing. See if they have any glazed spots on them.

-- Paul, Las Vegas

View bondogaposis's profile


4682 posts in 2316 days

#2 posted 04-03-2013 05:13 PM

Yeah, that was my thought too. Check the belt and pulley’s. Make sure the pulley’s are not slipping.

-- Bondo Gaposis

View CharlieM1958's profile


16274 posts in 4183 days

#3 posted 04-03-2013 05:16 PM

My first thought would be arbor bearings, although I would not expect the problem to occur at such regular intervals.

Here is a discussion you might find helpful.

-- Charlie M. "Woodworking - patience = firewood"

View PurpLev's profile


8534 posts in 3613 days

#4 posted 04-03-2013 05:18 PM

like the others suggested my first guess would be the belt.

if you can HEAR it – then take the belt off, and power up the saw and LISTEN. if you can still hear it then it’s the motor shaft bearings or the motor winding. if you can’t hear it then it’s most likely the belt (or the blade arbor). try replacing the belt and see if it clears it.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View Airspeed's profile


445 posts in 1867 days

#5 posted 04-03-2013 05:24 PM

Does it do it without cutting? Something is making the blade resonate, try a different blade, if it still does it you have a belt prob or the arbor is bad. I had this happen to my Unisaw, it turned out to be the nut, it was threaded crooked and putting more pressure on one side of the blade. My wife was helping me rip some long stock once and kept moving the boards to the side, it heated up the blade so much that it was ruined and did the same thing you describe, has your blade gotten hot recently?


View Fettler's profile


200 posts in 1962 days

#6 posted 04-03-2013 05:24 PM

Do you hear the motor slowing when that happens? Could it be that the wobble happens when you hit a denser bit of wood (a shadow of a knot)? Is there any noticeable play in the arbor?

That sounds like a pain to diagnose.

-- --Rob, Seattle, WA

View Clint Searl's profile

Clint Searl

1533 posts in 2326 days

#7 posted 04-03-2013 06:33 PM

There’s a bunion on the trunnion.

-- Clint Searl....Ya can no more do what ya don't know how than ya can git back from where ya ain't been

View IrreverentJack's profile


727 posts in 2808 days

#8 posted 04-03-2013 06:46 PM

Have someone watch the motor to see if you have a bounce – If your belt is too short or slipping the motor pulley can walk up the belt when you have blade resistance then drop down. If you stop the cut, does it stop? -Jack

View Mark Davisson's profile

Mark Davisson

597 posts in 3282 days

#9 posted 04-03-2013 06:55 PM

Clint gets the prize for comment of the day!

-- I'm selfless because it feels so good!

View Woodknack's profile


11479 posts in 2345 days

#10 posted 04-03-2013 07:38 PM

It only happens when cutting in the middle of a board, ripping or crosscut. When I say I can hear it, I mean I can hear the blade dig deeper into both side of the cut, sometimes causing a burn, everything else sounds normal. I cleaned the blade and checked all the extension tables for flush/level but it still happened.

It does not happen when: not cutting, cutting on the edge of a board, or taking light cuts. I inspected the belt recently and there is no fraying, hazing or bumps, it looks fine but I won’t rule it out.

@PurpLev – Something is making the blade resonate

Yes, well put. Something is causing a momentary resonance when cutting inside a piece. I made a new zero clearance insert on the off chance that my factory insert (which I normally use with the rip blade) is bobbling and causing the wood to shift. I’m getting ready to go test it.

-- Rick M,

View Grandpa's profile


3259 posts in 2640 days

#11 posted 04-03-2013 07:51 PM

My first thought was heat. That is usually caused by a dull blade.
My second thought is a slipping belt or a slipping pulley.

View JoeinGa's profile


7735 posts in 1972 days

#12 posted 04-03-2013 07:52 PM

”@PurpLev – Something is making the blade resonate”

Yep, and I’m guessing it’s HEAT. The deeper you cut into the wood, the hotter the blade gets. I think the heat is causing the blade to actually warp. And then as the blade slows it cools, making the blade stiffer again. Any chance you checked the blade for very small cracks? Heat would cause those to “open up”, thereby pushing the blade out of true.

-- Perform A Random Act Of Kindness Today ... Pay It Forward

View Woodknack's profile


11479 posts in 2345 days

#13 posted 04-03-2013 10:19 PM

Heat would make sense except it was my first cut of the day, through 4’ of 1/2” MDF so I can’t imagine that was the problem. I installed a splitter hoping it would fix the problem but after switching to a new zero clearance insert and installing the splitter it only happened once in a 4’ cut but it still happened. The blade isn’t very used, freshly cleaned, is relatively sharp. I was just up under the saw yesterday and didn’t see any problems. Tomorrow I’ll switch to a full kerf combo blade and see if it still happens. If the other blades cut fine I’ll send this one out for a sharpening/rebalancing.

-- Rick M,

View CarpenterMark's profile


5 posts in 1847 days

#14 posted 04-03-2013 11:56 PM

I’t’s the result of an overfeed with a less than sharp blade; slow down the feed and see if it stops.

-- Grow it, make it or catch it!

View jumbojack's profile


1674 posts in 2589 days

#15 posted 04-04-2013 12:09 AM

I am thinking a blade resharpen. You get the plus of a nice clean blade and I think it will cure your woes.

-- Made in America, with American made tools....Shopsmith

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