Bandsaw blade scorched

[Susumu Mori]

Hi all,

I need some expert opinions about a symptom I'm experiencing with my bandsaw.
I could finally set up my bandsaw up to my expectation. The cut is nice and clean without blade drift or wondering, but there is one think I'm concerned. When I cut a board wider than 10 inches, I can smell something is scorched. The wood is clean without marks. However, I can see the carbide tips of ResawKing have sign of heat. The wood dusts are hardened and adhered to the surface of the carbides with brown colors. My blade guards remain cool, only occasionally touching the blade. So the heat seems generated by the carbide tips contacting the wood. The ResawKing is still new.

Do you think it's normal? Maybe I'm pushing the wood too fast?

Your suggestions would be greatly appreciated.

[Erik Loza]

Wood is green or dry?

Erik Loza
Minimax USA

[Susumu Mori]

Dry poplar.
Should not be too difficult for the blade.
I guess the same for soft maple too.

[Erik Loza]

I've never personally used the RK blade but from what I remember, it has a pretty acute negative hook to the blade tooth, in addition to being flat-kerfed. With blades like that, they can be really sensitive to feed rate and pressure and you can burn the wood if not careful. It has nothing to do with the tooth material. It's the design of the profile and the grind. Like trying to rip hardwood with an high tooth-count ATB tablesaw blade.

Not sure how fast you are feeding the stock but what happens if you slow down a bit? The blade might already be dull.

Erik Loza
Minimax USA

[Duane Meadows]

I pretty well toasted a timberwolf blade resawing poplar. Poplar also repeatedly plugged the DC on my planer. Way worse than red oak. That said, I replaced the TW with a Lennox Woodmaster CT, so far that took the poplar in stride and any thing else I have run thru it. No experience with the RK.

Generally when overheating a blade, it is the inability to clear chips fast enough. From my experience that is tougher to do with poplar, and in looking at the tooth profile for the RK blade, it may make that worse. Just my $.02 worth.

[Jim Matthews]

Generally when overheating a blade, it is the inability to clear chips fast enough.

+1 on this.
Feed rate cannot exceed the chip ejection rate.

The chip carries the heat generated by the machining step.

Without applying coolant, woodworkers must slow this step to allow the chip (sawdust) to clear the kerf.
Heat generated by the process must go somewhere.

More resin in a particular board will also increase friction.

[Susumu Mori]

Thanks Erik, Duane, and Jim,

So, it sounds I have to slow down a bit. If I understood you correctly, the feed speed is determined mostly by the kind of the blade and the wood, regardless of how much power the BS has. Switching from a 3/4-horse to a 4-horse BS, I have been enjoying the amazing speed of the cut, but I guess, the power is not the only factor that decides the optimum speed.

I attached the pic of my ResawKing. You can see blown pitch building up. I scratched off the pitch (do you call it "pitch"?) from one of the tips with my nail. It comes off easily. I assume that this needs to be cleaned up occasionally to keep the blade performance?

photo 2 (1).jpg

[Myk Rian]

I'm looking at chipped teeth, gullets not cut the same, and no angle on the teeth.

[Erik Loza]

Ya, that blade looks torched, sorry to say. True story: I actually ruined a brand new 1.0" Lenox Tri-master in maybe less than 50 board/ft by pushing the cut a little to hard on some green ash. Blade dulled, then snapped. Negative-hook, flat-kerfed blade pushed too hard, then sawdust builds up in the gullets and traps tons of heat in the blade.

A couple of the pitfalls I see bandsaw users fall into semi-regularly..

1.) "I only need one or two blades". Depending on what you do, you could quite easily have half a dozen different blades and you can/may ruin a few along the way, getting your saw figured out.

2.) "Why can't I get a finish-quality cut from every blade, any species". Again, what are you really planning to do with the finished project? I talked to a gentleman the other day who seemd hung up on finish-quality cuts on bowl blanks. Why? There are blades which will do it for you (like the RK or like the carbides...) but also will require attention to to feed rate and pressure.

Susumu, I'm not saying any of this was necessarily the case with your blade but just things I have seen or experienced. Hope this helps,

Erik Loza
Minimax USA

[ken masoumi]

I'm looking at chipped teeth, gullets not cut the same, and no angle on the teeth.

I see the same thing,it could be the camera angle but the gullets are not uniform in that pic.

[Paul M Miller]

I think the non-uniform gullets are intentional. Some bandsaw blades are made with variable spaced teeth to reduce harmonic vibration for a smoother cut.

[Susumu Mori]

Hi all,

Thank you for all the inputs. It just occurred to me that I bought a pitch remover in the other day.
So I gave it a try. It was just amazing to see how much pitch was there on the blade. I removed a huge amount. It took quite some time to clean the blade thoroughly.
It was also amazing to see how much pitch I get from just one 10-inch board of poplar. Maybe the particular poplar I was cutting was resin-loaded. In any case, now my blade is clean as shown in the photo. It cuts with much less effort, but I'm trying not to cut too fast to avoid heating and resin adhesion. I didn't expect that I had to clean the blade this often, but once I learn how to do it, it won't take that much time. For a small amount of pitch, I can wipe the blade with a lug sprayed with the pitch remover as I turn the wheel backward (not sure if this is the right thing to do, though). Knowing how much degradation of the blade performance we get by the pitch, I would clean the blade frequently from now on.

photo (3).jpg

[Jim Matthews]

So once cleaned, you can again cut straight with this blade?

[Susumu Mori]

yes, the cleaned blade definitely cuts better with less force. Now the blade doesn't reach the thrust bearing that was set 3mm behind the blade. It cuts very clean for about first 5 inches or so, but then starts to have some irregularity in the surface, suggesting I may be still getting some heating. However, I stop cutting my stock poplar just for checking the setup and testing, knowing how much pitch the blade gets. I don't want sacrifice my maple, cherry, and walnut just for the testing. So, I'm not sure if it cuts as good as it was new. I have to wait for my next resaw project. I just hope that it won't give me disappointment, but now I have good feeling about it.