Planer knives

[Greg McCallister]

Besides a streak or chipped blade, what signs do you look for that show the knives on your planer are getting dull?
I changed mine not that long ago but I am starting to get what I call rip out or chunks torn out. Is that the first sign of dull blades?

[James Suzda]

Besides a streak or chipped blade, what signs do you look for that show the knives on your planer are getting dull?
I changed mine not that long ago but I am starting to get what I call rip out or chunks torn out. Is that the first sign of dull blades?
The first thing I notice is how much harder the machine is working, or in the case of the 735 the feed rollers start to slip a little.

[Frank Drew]

Greg,

Blades start getting dulled with the first cut, even if too little to tell; it's a continuum from sharp like new to hopelessly dull, and you'll notice somewhere along the line that the blades need to be replaced/sharpened.

In industry, they don't rely on the operator's subjective assessment of the cut quality but rather measure the electric draw to tell when the dull blades are causing too much current to flow in order to do a fixed amount of work. They're measuring what James is noticing, but probably sooner.

[Steve Griffin]

Sound. Once the sound level goes up from "loud" to "unpleasantly loud" , I know I'm due to replace the knives.

Also if you see an increase in chip out.

It's good to have two sets of knives--one can be out for sharpening and you are not shut down. By the way, having two sets of knives and blades for everything doesn't cost you a penny more than a single set--I figure everything lasts twice as long if you have twice as many!

-Steve

[Anthony Whitesell]

I would agree, that an increase in tear out will also occur. If you reach that point, they're really worn out.

[Kevin Godshall]

I 2nd the thoughts of those above: the machine will begin "telling" you, louder and louder and quality of cut gets progressively worse.

Also, keep an eye on the chips, shavings, dust you are making. When you get less shavings, more and more chips, and more and more dust, swap em out.