Bad Saws Run Wrong

[Tom Walz]

Or why you need to be careful with saw blades

Thin kerf saw blades run in a gang.

I thought I would post this for those of you that have neverseen saws come apart. These were good saw blades; good steel about 0.080" thick.

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[curtis rosche]

What does it take to make a blade do that? metal fatigue or did it hit something?

[Troy Turner]

So not all saw blades are created equal ;)

[Matt Day]

Could you post some more details about this? What type of saw, what was being done when things went wrong, etc. Your point isn't very clear without the circumstances.

[John TenEyck]

Either those blades are tiny or the shaft was huge. I'll bet the circumstances of failure were something way out of the norm compared to what most here do, and I'm as interested as the others in hearing more.

John

[Art Mann]

Is the OP saying that because those blades failed in some, as yet, unexplained way that the same thing will happen to all thin kerf blades? Those are obviously not typical table saw blades.

[J.R. Rutter]

They must have been running on a gang rip saw, where multiple blades are spaced onto a single arbor and fed by a wide chain drive. Since the arbor motor can be upwards of 50-60 HP and the saws are capable of pretty fast feed rates, blades could potentially see a LOT of torque. What exactly happened? They look as though they were installed backwards!

[johnny means]

Look to me like they where beaten to death to remove them.

[Tom Walz]

Those were 8” saw blades for a pallet mill. They were run as a gang on a big arbor withcollars.

They were sent to me for analysis. They were the wrong design, very poorly madeand run on poorly maintained equipment. The saws crashed due to a mis-feed.

One saw had a 0.070” plate and another had 0.060”plate. Kerf measured from 0.105” to0.120” but a lot of teeth were missing. It is your call whether that is thin kerf or not.

I mostly put these up because I thought they were interesting. I also thought they did a pretty good job ofshowing the kind of power a saw blade has.

I have been looking at bad saws and failed saws for about 30years trying to figure out how to make better saws. Maybe that has made me toocautious however some folks here recommend thin kerf saw a little more freelythan I do. I amalso hesitant to see a saw blade used in an application for which it was notdesigned.

The two best sources I know of for thin kerf information are:

Bruce Lehmann, Ph. D.
http://www.thinkerf.com/ (http://www.thinkerf.com/)

John Schultz
http://www.superthinsaws.com

[Gus Dundon]

When I saw the photos, I think that it's hopeless.

[Art Mann]

It sounds to me like the failure was unrelated to the thickness of the plate or saw kerf. With high power, poor maintenance and defective blades, this kind of disaster can happen no matter what the blade geometry. I don't see how this disaster has any applicability to the average woodworker with the exception that it illustrates the need to maintain one's equipment and saw blades properly.

A good thin kerf saw blade can turn a marginally powered saw into a good performer. I consider the risk associated with forcing wood through an underpowered table saw to be greater than any risk associated with using thin kerf blades.

[John TenEyck]

It sounds to me like the failure was unrelated to the thickness of the plate or saw kerf. With high power, poor maintenance and defective blades, this kind of disaster can happen no matter what the blade geometry. I don't see how this disaster has any applicability to the average woodworker with the exception that it illustrates the need to maintain one's equipment and saw blades properly.

A good thin kerf saw blade can turn a marginally powered saw into a good performer. I consider the risk associated with forcing wood through an underpowered table saw to be greater than any risk associated with using thin kerf blades.

Well said. Has anyone ever seen a saw plate fail on a table saw, thin or full kerf ?

John

[johnny means]

Well said. Has anyone ever seen a saw plate fail on a table saw, thin or full kerf ?

John

I think those of us who have triggered our Sawstops would attest that saw plates don't fall like that.

[George Gyulatyan]

Gulp!
.....

[Michael W. Clark]

I think it is good to see what can happen in industrial/commercial applications. Thanks for posting Tom!
Mike

[Rick Potter]

That is really interesting Tom. I had no idea they used that much power in gang saws.

Rick Potter

[Kent A Bathurst]

That is really interesting Tom. I had no idea they used that much power in gang saws.

Rick Potter

Ya gotta. If you are going to run 2x material 8" and up, 50 HP is the ante. We run one at 75.

But - realize we are talking 80 lfpm and up for feed speed.

[David Hawkins]

I was present when a foreman was setting up a miter saw and he was so busy "teaching" that he forgot to take a 24" carpenter's Square off the guides before starting a demo cycle with the saw turned on..... very lucky no one was hurt, carbide flying all over the place.... foreman retired a day later....