circular sawblade deformation

[lumberdad]

My 7 1/4" circular saw blade has permanently deformed into a cup shape which is circularly symmetric about the arbor bore. The blade was sharp and new with carbide teeth and had previously cut accurately. The center is now about 1/32" higher than the toothed rim causing the cutting edge direction to be misaligned with the desired direction of the cut.  Obviously, this causes severe wander and binding. My solution was to get a new and better blade.  I am curious, however, as to what could cause this. I would appreciate some insight from others who have seen this. Loss of blade metal temper from blade heating would be my guess, but I've never had that happen before.

[lift mechanic]

I have never had that happen, only thing, i think, that would cause a blade to warp would be heat. Maybe a board pinched the blade during a cut causing the heat?

[Willyou]

I have had that happen. Yes. It is caused by the blade getting too hot. It has been a while, but as I recall, I was using the saw with the sole plate against a guide. I discovered later that the edge of the sole plate was not parallel with the blade and the blade was actually angled inward toward the guide. It got real hot.

[Stwood_]

I would also think heat

[tomsteve]

ive had 7 1/4 blades warp from heat. let the saw run for a bit afyter a cut that builds up that much heat. let the blade make its own fan to cool it back down while spinning.

[Bill_de]

ive had 7 1/4 blades warp from heat. let the saw run for a bit afyter a cut that builds up that much heat. let the blade make its own fan to cool it back down while spinning.

I wonder if over tightening the bolt that holds the blade, in conjunction with the heat, could exacerbate the situation.

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[lumberdad]

ive had 7 1/4 blades warp from heat. let the saw run for a bit afyter a cut that builds up that much heat. let the blade make its own fan to cool it back down while spinning.

Thanks for your comment. The deformation I described is permanent. No amount of cooling can reverse that at this point. Whatever happened was not a reversible thermoelastic process. Maybe heat induced internal stress relief. I just would not have thought it got hot enough for that.

[KyleD]

I had that happen once. Was ripping 5\4 red oak on a thee horse table saw using a circular saw blade for the thin kerf. The cut closed pinching the blade. I couldn't push the wood through anymore. By the time I got the saw turned off smoke was rolling off the cut. When I pried the wood off the blade it warped into a shallow bowl shape with an audible ping. Needless to say the blade was trash.