Table saw blade harmonic, wag or flutter

[Quesne Ouaques]

I recently got a new (for me) Craftsman table saw #113298762

Before I bought it two months ago, the saw sat unused -- like new -- in a clean, dry garage for more than 15 years.

I did set it up and adjust it so that the blade is parallel to the miter slot and fence. The fence -- though original -- does appear to consistently lock straight and parallel to the blade.

On startup, there is a very slight "shimmy" as the blade spins up. I'm not sure, but it appears to me that it's due to the shape of the belt. The belt sat unused on the saw for many years, and it developed some shape "memory" (i.e. an oval rather than a circle). Other than that, the saw runs very smoothly when up to speed.

The problem I am having is what appears to be a slight "wag", flutter or harmonic only noticeable at the back of the blade as the wood exits. It is most pronounced with the blade fully raised and cutting through relatively thin stock (3/4 to 1 inch). In that case, the flutter is as much as 0.01 (ten thousandths), measured as the depth of an overcut kerf on the workpiece.

When I lower the blade and cut the same piece of wood with the blade gullet valleys right above the surface of the wood, the overcut depth is much shallower at .002 (two thousandths).

I have seen this same behavior with two brand new 50 tooth combo blades (Dewalt and Oshlun; normal kerf) as well as an old HF POS thin kerf blade that came off my old saw (the "wag" is a bit less with the thin blade). I have not yet been able to test runout directly at the arbor, but runout on the blade at 1.5 inches below the gullet valleys measures .0035

Has anyone experienced this kind of thing before? What tests could you suggest I perform to further diagnose the problem?

Any help or comments would be much appreciated.

[Rick Potter]

Two things.

First the belt. Dump it and get a new one, or preferably a link belt. Once a belt sits that long with weight on it, it will bounce like an old tire that has been sitting.

For the wobble, the first thing I would check is the arbor flange. Maybe it has some rust or grit on it that causes the blade to wobble?

RP

[Erik Loza]

Two things.

First the belt. Dump it and get a new one, or preferably a link belt. Once a belt sits that long with weight on it, it will bounce like an old tire that has been sitting.

For the wobble, the first thing I would check is the arbor flange. Maybe it has some rust or grit on it that causes the blade to wobble?

RP

+1 on all Ricks's points.

One thought: Any possibility that the saw's arbor shaft is slightly undersized compared to the arbor bores in the blades? That a blade could be installed slightly off-center?

Erik Loza
Minimax USA

[Lee Schierer]

I agree with Erik. To add one more thought to his ideas. If this is a Craftsman blade, dump it and get a good Carbide blade. As the owner of a Craftsman saw and several Craftsman blades than now hang on the wall un-used due to poor cutting as compared to the quality of cut of a Freud Blade. Get a dedicated crosscut blade (LU82M or LU73M) and a dedicated 40 tooth rip blade. The rip blade probably should be thin kerf.

[Jim Andrew]

I used to be a tightwad when buying blades, learned that to get a quality blade, you really need to buy a blade that costs more than the bargains at the local box store.
I ordered some blades from Carbide Processors, Tenryu brand, crosscut and rip, and they cut so much better than any other blades I have ever owned.

[Don Wurscher]

I have a Craftsman Table saw that I have been using for almost 40 years, and belts are a major problems with my saw causing vibrations, as suggested a link belt is the way to go. Another thing with some of these saws is that the arbor shaft diameter on the very inside next to the flange is smaller then at the nut end. This is not a problem when just sawing, but can be a real problem when trying to cut flat bottom dado's. I solved this problem by using blade stiffeners, you loose some max width, but the bottoms are flat. Another thought replace the fence, I just put the old one in storage and ordered a replacement from Grizzly.

[Don Huffer]

Your really going to have to make sure this saw is in tip top shape and tuned the best you can in order to get good results. I agree with all the comments above and would add. Throw away the fence as soon as you have mounted a better one. Those fences will cause you 99% of your problems. Once you do that your saw will preform like most other saws and you will actually enjoy using it.

Secondly. Build a sled and set the miter gauge off to the back side of your shop to only be used when you have too.

Don

[John TenEyck]

Have you tried cutting from the other side of the blade and verified the same runout at the back of the blade? Better yet, use your miter gage and make cuts on both sides of the blade to prove it's blade flutter and not the blade not being parallel with the miter slots. If it turns out that it really is blade flutter check the arbor flange for any crude, as already recommended. The fact that you've seen the same problem with two new blades of different brands suggests it's not related the blade. Of course, change that belt too, before you do anything else.

FWIW, I've had a CI Craftsman saw for over 30 years. I've built a lot of furniture and other things with it. Despite what many say, you can do good work with it. The fence is a PITA sometimes, but it was 25 years before I replaced it. The biggest negative, however, and one not easily corrected although it's possible, is that the blade will not stay parallel to the miter slots when you tilt it.

John

[Quesne Ouaques]

Thanks very much to all for the advice and commentary. It is much appreciated, and very helpful. Here is a quick followup on what I have done so far along with results.

I did check the dimensions of the arbor compared with the center holes in the blades. There is no measurable (or apparent) difference when I use a caliper micrometer.

Two things that really seemed to make a difference:

1. I cleaned the arbor shaft, arbor flanges, arbor nut and blade plates with mineral spirits. This alone brought the blade runout down to just over .004"

2. I "braced" the motor against the underside of the back edge of the table with a wooden spacer. This kept the belt relatively tight and removed any startup shimmy whatsoever. Definitely need a new belt!

Once I did those two things, I re-tested that the blade is parallel to the miter slot. I cut a test piece on the front of the blade only, then shut the saw off. With the saw unplugged, I measured the space between the teeth and the workpiece both at the front and back of the blade (rotated the blade so I was measuring with the same teeth each time). Clearance was extremely tight at about .001"

I am still noticing a very slight amount of wood getting "spit" off the rear of the blade as my ripped workpiece gets pushed through. As recommended, I am shopping around for a good after-market fence. There is a brand new one available for a decent price in north Jersey (stock fence off of a Steel City saw). I hesitate only because the hole spacing on the rails is not the same as on my Craftsman. Any comments / advice on that?

Thanks again for the advice! Greatly appreciated.

[Quesne Ouaques]

1. I cleaned the arbor shaft, arbor flanges, arbor nut and blade plates with mineral spirits. This alone brought the blade runout down to just over .004"

A quick comment on my update from yesterday:

Looking back at my original post, I realize that the runout was always about .004 inches. Hastily typing yesterday, I confused blade runout with another of the many measurement I've been taking. My apologies!

[Quesne Ouaques]

A quick update for the curious and for those generous folks who gave me advice:

I picked up a v-link belt today and installed it on the saw. I could not BELIEVE the difference. The saw hums with virtually no vibration at all. I did both nickle and penny tests on the top, and they stood up through four complete on-off power cycles.

When I passed that same piece of 1" pine stock through the saw (blade fully raised but without the guard/splitter installed), the finish on the work piece was
much better. There were some light striations on the wood from the back-end of the blade, but no deep gouges like before. I did still notice a very little bit of wood getting "spit" up into the air off the bottom edge of the waste piece.

I then installed and adjusted the guard/splitter for tight blade clearance, and the resulting cuts are now nearly perfect. The only striations I see are visually apparent only. You can not feel them at all. The waste piece also seems to stay away from the blade.

Bottom line is that the saw now cuts about as well as I could have ever wanted. My guess is that a new fence (when I get one) will give me another step up in performance.

Thanks again to everyone for the advice and ideas. I greatly appreciate it :-)

[Myk Rian]

What I find interesting is 2 people telling you to throw the fence away, but with no explanation as to why.

[Don Huffer]

What I find interesting is 2 people telling you to throw the fence away, but with no explanation as to why.

It's not accurate. Won't stay aligned. Hard to set correctly compared to a good fence. Not long enough to aid in cutting long boards. Once set and locked you can't be sure it's in line. It's the most important part of the saw and used so much. Experience the joy of woodworking when you have a good fence. It will also enable you to resell the saw in a heart beat.

Your not going to find a single person that wasn't pleased beyond words when they mounted a new fence on their table saw.

Don

[Rick Potter]

So,

How did that router work out on the RAS frame?

Rick P

[Quesne Ouaques]

It works great Rick, thanks for asking!


I just used it a few weeks ago to joint and plane two hickory panels. One light pass through a friend's thickness planer at the end and they were perfect. My most recent project is jointing/planing coaster blanks that I make out of cross-cut tree limbs. I've done them a few times in the past, and they are especially hard because of the 360 degree grain pattern. This tool does them in 30 seconds. I took videos of both activities, so I'll edit and post them soon.


Over time, I suspect it could become a bit like that old saying for the bandsaw (i.e. it's the "problem solver" in the shop). I can imagine running into all sorts of planing, shaving, plunging and micro routing operations that this thing can possibly do.


The one need I do see is for a good travelling/sliding vice system to hold work and move it incrementally. I'll keep experimenting over time, and I am sure the table and setup will evolve. But it was a project worth pursuing, for sure.

[Jerry Olexa]

Happy for you with the V Link belt...

[Myk Rian]

It's not accurate. Won't stay aligned. Hard to set correctly compared to a good fence. Not long enough to aid in cutting long boards. Once set and locked you can't be sure it's in line. It's the most important part of the saw and used so much. Experience the joy of woodworking when you have a good fence. It will also enable you to resell the saw in a heart beat.

Your not going to find a single person that wasn't pleased beyond words when they mounted a new fence on their table saw.

Don
Thank you.