Is this blade now unsafe to use?

[Ty Williams]

Tonight, I was ripping some 8/4 hard maple to make yet another cutting board. I had bought 3 planks from Woodwerks on the same day, and all 3 have given me problems, but I was working with the worst of them tonight. The planks all have had immense internal stress, but this one was so bad I threw the rest of it out lest I accidentally use some of it in the future. The wood actually had so much tension that, even with the riving knife in place on my PCS, it actually grabbed the saw blade tightly enough to make the motor stall and trip out. The scary part was that I could feel it give just a bit of a lurch back towards me (thankfully, I was standing off to the side) before it clamped down solid and stopped the saw. Anyway, it locked on to the blade so tightly that I actually had trouble removing the wood. I couldn't pull it off and I couldn't lift it off. I was eventually able to lever it off by lifting the end nearest me and letting the far end jam against the table to serve as a fulcrum but I had to put some serious wellie into it to get it to shift.

No part of the blade seemed damaged on a quick visual inspection, so I threw out the Wood of Death and kept going with a different board. Now, a few hours later, I'm second-guessing whether this blade is still alright or not. Since it's pretty expensive (WWII), I don't want to trash it just on a suspicion, but at the same time my safety is worth a lot more than a saw blade. What do you guys think?

[John Coloccia]

Well, I won't address the blade issue because frankly, I don't want the liability. Personally, I would run the blade and if it didn't wobble or have any additional vibration, I'd probably run it, but that's just personally what I would do and I would never recommend doing that, and that's what I said if they ever ask me. :cool:

You should return that wood, though, and get a refund. It's almost certainly case hardened and that's from improper drying, not wood just being wood. That's just my opinion.

[dan sherman]

If you have a dial indicator, I would check and make sure you didn't bend the blade or the arbor, other than that I would just run it. I wouldn't throw the wood out though, I'd take the wood back and demand some form of compensation, or at the very least that they pull that batch for safety reasons.

[Bob Michaels]

First check that each and every carbide tooth is factory tight. Then check for run out with a gauge, both on the carbide tips and the body. Even if you find runout it's possible the saw wasn't tuned perfectly prior to the issue. To me, a loose carbide tooth is very dangerous. You could also send it back to Forrest and have them check it out and put it in factory condition for a lot less than a new WWII. Best of luck.

[Dick Latshaw]

When that little voice in my head says "Is this really a safe thing to do?", my answer has always been "No, it's not." Send that blade back to Forrest. Then you won't have to wonder if you are going to get a piece of carbide shot at you every time you run the blade.

[Steve Rozmiarek]

Thats an expensive way to cut firewood. Did it cut or act any different when you were using it after the incident? I'd think a failure would have happened right after but maybe not. Not saying your blade is ok, but I've done this once with a tablesaw, once with a chop saw. In both instances, the blade was fine. The other guys gave you good advice IMHO.

[John Downey]

I've done that, blade should be ok as long as you didn't pry against it or bend it removing the wood. If the blade were bent it would be obvious laying it flat on a bench.

I hate cutting 8/4 maple. One route is to first rip it on the bandsaw and just let it bend. You have to cut it quite a bit oversize if it's a long piece, so you can then straighten it again and rip just 1/8" or so off to finished width. In many cases, I doubt the usefulness of using such wood in furniture, as I suspect it will just keep moving over the years.

[Matt Meiser]

Easy out--send it to a reputable sharpener, even Forrest themselves to check out and include a note about what happened. I have blade I bent (stupid mistake involving a zero clearance insert and tilting the blade) that was straightened for me. Its not the blade it used to be but its definitely a very usable blade. I would assume Woodwerks has a reputable sharpener they work with, or even do it themselves.

[Ty Williams]

Well, based on your input, I ordered a new Forrest WWII 40T thin kerf blades and a WWII 20T Fast Rip blade. The WWII 40T TK that got locked up on last night is going out to Forrest to be inspected. I'm hoping the Fast Rip blade will make less stressful work of all this.

I'm very surprised to hear several of you say I should return the wood because of this. I never would have thought wood is a returnable commodity when you find something wrong with it.

[Steve Baumgartner]

Agree with the others about checking the blade. If it seems ok, it probably is, but err on the side of caution.

For reference in case this ever happens again: Don't try to pry the wood off the blade! Drive a wedge into the kerf behind the blade to spread it apart. The board will then lift off easily.

Steve

[Phil Thien]

Maple can be the biggest PITA when ripping, I've often experienced exactly what you describe.

That is why on thicker stock, I do my initial rip on the bandsaw to break it down into manageable stock.

John maybe right, it may be case hardened. I've had it happen to me enough, and specifically with maple, that I suspect some of the blame is with the species.

And I wouldn't try to return the wood, I wouldn't toss it either. I'd just rip it up on the bandsaw and use it.

[John Coloccia]

I'm very surprised to hear several of you say I should return the wood because of this. I never would have thought wood is a returnable commodity when you find something wrong with it.

It depends what's wrong, but case hardening is usually pretty obvious. No matter where you cut it, both sides of the kerf close up as you cut. That's classic case hardening, is a direct result of poor drying and is something you shouldn't pay for. Now if I cut into it and found some bad runout, or maybe even voids or something like that, I'd just eat that and chalk it up to dealing with a natural product. If it was just some reaction wood that went all looney as I started cutting, same thing. If it's case hardened, it goes right back whence it came.

Honestly, I usually have no problems with Maple...I'm surprised to read that so many do. Maybe I just have a very good supplier? I have had trouble with walnut in the past, but not from case hardening. My maple seems to all be good, though! :)

[Ty Williams]

For reference in case this ever happens again: Don't try to pry the wood off the blade! Drive a wedge into the kerf behind the blade to spread it apart. The board will then lift off easily.
That would be my normal tactic as well, but this one was unlucky enough to lock up exactly where the blade and riving knife filled the kerf and there was nowhere to stick a wedge. Another inch and I could have started to spread it from the back to loosen it up.

[Jeff Duncan]

It's pretty normal for maple to move when you cut it, and it's also pretty common for it to close up on a blade when your ripping 8/4 stock. I've cut literally thousands and thousands of bd. ft. of maple over the years and it's rare that it doesn't want to move during a rip. I'm not recommending anyone do this, but when I'm dealing with a particularly funky batch of wood I keep a stack of shims on my table saw. I run the board through the blade and once I have a foot or so past the blade I drop a shim into the kerf and proceed. Again, not recommending it to anyone and especially not anyone who isn't very comfortable feeding a saw, but it works for me in a pinch.

Also, you didn't mention, but when you pried the stuck board off did you move the fence out of the way first? That's your first step, then if it's still really tight hammer a wedge into the kerf so as not to fight the blade;)

As far as the blade goes it's probably fine. Sending it out will give you that extra assurance though so you can feel comfortable using it. I couldn't count the number of times I've had wood lock up on blades whether the table saws or the RAS's or even chop saws. Blades in general I've found to be pretty tough as long as you don't slam into them. It's that "shock" that can wreak havoc with the carbide teeth.

good luck,
JeffD