How do I know it's time to replace my circular saw blade?

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I only use my table saw and circular saw, both with ripping blades, a few times a year. How can I tell when it's time to replace them?

I imagine I'm not going to lose them to wear, but then again, maybe I've hit an occasional nail. I don't know whether storage and rust cause degradation or if any rust is superficial and gets knocked off when I use them again.

feetwet

Posted 2015-03-17T18:16:23.547

Reputation: 650

Answers

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Your blade will start to show signs of dullness. These include:

  • Binding
  • Excessive force required to advance cut
  • Excessive tearing/chipout
  • Burning the wood

It helps if you can remember the "feel" of cutting with a sharp blade to help recognize these signs. One of them alone may be a result of improper technique. But when multiple signs stack up, you can be more sure that it's time to switch out blades.

Doresoom

Posted 2015-03-17T18:16:23.547

Reputation: 3 118

Same question/answer can be found on DIY.SE, but I believe it's also relevant and important to keep on the woodworking site as well.

– Doresoom – 2015-03-17T18:23:28.697

One problem is that because my use is so infrequent, and my materials so varied, I don't have a good baseline for what to expect and hence what would be "excessive." – feetwet – 2015-03-17T18:23:30.007

1You could try sliding a board across your table saw table without the saw running. As long as you're not forcing the cut, advancing it slowly through the blade while ripping shouldn't require significantly more force than that to overcome friction. – Doresoom – 2015-03-17T19:18:38.953

Wow: then either I'm trying to feed way too quickly, or I have kept my current blade way too long! – feetwet – 2015-03-17T19:32:44.700

@feetwet, keep in mind the amount of force required will vary with your stock, as cutting a thicker board will offer more resistance than a sheet of plywood. – Doresoom – 2015-03-17T19:44:36.593

1@Doresoom ... pine will be a lot easier to cut than a hardwood will be, as well. – Pᴀᴜʟsᴛᴇʀ2 – 2015-03-17T21:35:12.630

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Sometimes when people believe their saw is dull, what it really needs is a cleaning. The resins from the wood build up in the teeth over time and gum up the cutting edge. Soaking the blade in simple green or another cleaner of choice and then scrubbing the teeth with an old toothbrush can prolong cutting life.

Peter Grace

Posted 2015-03-17T18:16:23.547

Reputation: 2 485