# How to tell when carbide turning tools are dull



## Lookwow (May 12, 2018)

I know this seems like a stupid question. But I have a hard time telling.


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## smokie (Dec 29, 2012)

When you tool doesn't make a clean cut (more dust than usual).
When you find your pushing or forcing the tool, it's off to the grinder. 
JMTCW


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## TheDane (May 15, 2008)

> ... it's off to the grinder.


I don't think I would take a carbide tool to the grinder. Maybe touch it up with a diamond plate instead.

I have a couple of carbide tools … they never get dull because I avoid using them.


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## Nubsnstubs (Aug 30, 2013)

I've always heard from my sharpening services that if you can see the edge, it's dull…...Jerry (in Tucson)


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## rwe2156 (May 7, 2014)

Lets see, increased feed pressure, more tear out.

If you seen burn marks, it needed sharpening 6 months ago…...

ALWAYS have your carbide blades and router bits sharpened professionally. A grinder will bolux it up and a nano second.


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## LesB (Dec 21, 2008)

Some small tools like router bits can be touched up a time or two with a diamond sharpener but for the most part it is best to take them to a sharpening shop; especially saw blades. A good saw blade can usually be sharpened at least 3 times and if there is a broken or chipped tooth the shop can usually braze on a new one. It takes a lot of practice to sharpen a carbide planer blade so I wouldn't even try although in a pinch you might make light passes along the straight back edge with a very fine diamond sharpene rto tune it up a little.

As stated previously if it takes more pressure to make a cut, if the cut is rough, of you can actually see light reflect off the edge it is time to sharpen them. You can also educate your fingers to feel for sharpness. The human finger is sensitive to 1/10,000 of an inch. Just compare a new sharp edge to your worn one to see the difference. Keep some bandages handy….LOL


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## redlee (Apr 11, 2016)

Lightly drag youre fingernail across the edge,it should make shavings.
I agree with Nubsnstubs , if you see a slight reflection from the edge its dull.


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## LeeMills (Nov 2, 2014)

Here is a good video on sharpening carbide cutters. I do basically the same.





Here is a video on what to look for in the diamond plates. It may be an ad but I think it is correct.





I bought some cheapies that did not last long but my good one (over $30 back in the 80's) is still going strong.


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## Sparks500 (Jun 30, 2017)

Dullness can creep up on you. Years ago I bought a Forrest 10" standard blade and was amazed at how well it cut. As time went on, and I was still working, so the shop was only used occasionally, the blade got dull, but with a 3HP Powermatic saw, I didn't notice. 
Got to where I was going to work on a pretty nice project and finally inspected the blade: 5 teeth MISSING, and all the rest looking pretty rough. I felt like an idiot for letting it get so bad, but, I packaged it up, sent it back to Forrest, and, $90 later I had a blade cutting better than new.
I'm the one that's dull…...
Needless to say, I pay more attention now…...


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## MrRon (Jul 9, 2009)

> Dullness can creep up on you. Years ago I bought a Forrest 10" standard blade and was amazed at how well it cut. As time went on, and I was still working, so the shop was only used occasionally, the blade got dull, but with a 3HP Powermatic saw, I didn t notice.
> Got to where I was going to work on a pretty nice project and finally inspected the blade: 5 teeth MISSING, and all the rest looking pretty rough. I felt like an idiot for letting it get so bad, but, I packaged it up, sent it back to Forrest, and, $90 later I had a blade cutting better than new.
> I m the one that s dull…...
> Needless to say, I pay more attention now…...
> ...


Replacing 5 teeth is what costs. Fortunately I have carbide saw sharpening equipment (Foley) that I use to maintain all my own carbide sharpening needs.


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