When is blade dull & ready for replacing/resharpening?

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Forum topic by ScottinVa posted 02-18-2015 09:38 PM 1102 views 0 times favorited 10 replies Add to Favorites Watch
View ScottinVa's profile


39 posts in 1479 days

02-18-2015 09:38 PM

Topic tags/keywords: question

Is there a rule of thumb to determine if a table or miter saw blade is too dull to continue? I was using my Delta miter saw yesterday on some 8/4 cherry and it burned some if it. I adjusted to cut on the slide and it was better, but still seemed slow. Any suggestions? Thanks.

10 replies so far

View knotscott's profile


7980 posts in 3339 days

#1 posted 02-18-2015 10:08 PM

When they get gummed up, they cut like they’re dull, so the first thing I’d do is clean it if you’re not in the habit of doing that. Generally, if a blade is dull, it will be harder to cut with, have more resistance, won’t cut as cleanly as before, can leave burn marks, etc. If you haven’t been cleaning it regularly, the pitch on the teeth will cause excess heat, which breaks down the carbide, making it go dull sooner.

-- Happiness is like wetting your pants...everyone can see it, but only you can feel the warmth....

View Redoak49's profile


3193 posts in 1952 days

#2 posted 02-19-2015 12:16 AM

I find d that cherry is easy to burn and sometimes you need a sharp blade and the right type.

The tip is right on about keeping the blade clean.

View greenacres2's profile


319 posts in 2131 days

#3 posted 02-19-2015 02:53 AM

I’ve not been at this very long, but once i started keeping my blades clean—it’s become a habit. I’ve been using Trend Bit & Blade cleaner, but i’m sure there are other good (probably better) products as well. I clean after every session. It’s amazing what a difference it makes. If i don’t let them get gummed up and the blade or router bit is off the tool, it’s really not much more than a damp wipe and dry—couple of minutes at most. I keep a plastic paint tray handy (a bucket lid would be so much better), old t-shirt pieces, plastic brush.

Cleaning my cutting tools is the best habit i’ve got, and i owe that to people like Scott and many others who have been strong advocates. Your mileage may vary.

And as Redoak said—cherry scorches easily. I’ve gotten better at working with it, but learning to feel the feed is tough. (it also helps to watch some videos of the gurus and catch a glimpse of the same kind of marks i make—doesn’t make them go away, but it does allow me to forgive myself!!)


View daddywoofdawg's profile


1028 posts in 1538 days

#4 posted 02-19-2015 04:00 AM

If what your cutting looks like a beaver chewed though it,or it seems like you could cut it by hand faster you may have a dull blade,also if you have cut 1000’s of bf oak,rock maple,ironwood you may have a dull blade.

View GrandpaLen's profile


1650 posts in 2236 days

#5 posted 02-19-2015 05:28 AM

Cherry burns quite easily, if your blade and fence are not parallel it will be even worse.
When you rip a board, rip it about 3/16” wider than your final width needed and then trim the edges that are burned to arrive at your final width..
The less you are trimming off, the less heat is generated.
A lesser quality blade, that causes burning, can be compensated for, in this manner.
If that blade is truly dull, it’s a ‘Kick-Back’ waiting to happen.

Best Regards. – Grandpa Len
Work Safely and have Fun

-- Mother Nature should be proud of what you've done with her tree. - Len ...just north of a stone's throw from the oHIo, river that is, in So. Indiana.

View ScottinVa's profile


39 posts in 1479 days

#6 posted 02-19-2015 06:09 PM

Thanks all. I’ll give a solid cleaning and check the results before buying new.

View exelectrician's profile


2327 posts in 2390 days

#7 posted 02-19-2015 07:11 PM

If you think it is dull – It Is Dull!

-- Love thy neighbour as thyself

View ElChe's profile


630 posts in 1300 days

#8 posted 02-20-2015 12:22 AM

After cleaning, I’d look at the teeth. Any chips? I feel the tips by first running my finger over the tip. Do they feel sharp? I look at the teeth individually under a light. Is the bevel nice? At the cutting edge do they look good or is the edge starting to reflect some light indicating some dulling at the tips? Test cuts after cleaning and inspecting. Are the cuts acceptable? I tend to go too long between sharpening because I clean up edge grain with shooting board and glue lines with a jack plane.

-- Tom - Measure twice cut once. Then measure again. Curse. Fudge.

View devann's profile


2246 posts in 2656 days

#9 posted 02-20-2015 12:42 AM

Ditto what the exelectrician said. Check around, I’m sure there is a local that can resharpen your blades.

Get you a can of bostik dricote lubricant. It’ll cut down on how fast the pitch builds up, & keep the blade cooler while cutting. Cooler cutters stay sharper longer. You may think it’s kinda pricy, but I’ve used it for years and it’s really a bargain in the long run. I started buy it when it was made by Sandero, they were the original manufacturer.

-- Darrell, making more sawdust than I know what to do with

View timbertailor's profile


1594 posts in 1387 days

#10 posted 02-20-2015 01:49 AM

I keep test boards around for just this.

Keep a piece of scrap and cut it with a new blade.

When you start seeing signs that the blade is dulling as described above, take out your test piece and cut it again.

If you start seeing discoloration that is darker than the original cut when new, and it has been cleaned, it is time for sharpening.

-- Brad, Texas,

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