Author Topic: what to expect when a blade breaks? (Read 1529 times)

stormyweatherman · « **on:** July 27, 2010, 07:10:03 pm »

haven't broken a blade on my mill yet (lt 10) and very curious about what to expect? does the blade just sit there? does it shoot out the side? is it unpredictable? how dangerous, etc.? thanks in advance for any help.

Planman1954 · « **Reply #1 on:** July 27, 2010, 07:20:46 pm »

When my blade breaks, it sounds just like when the band is broken on a banded stack of new lumber at a lumberyard by someone loading your stuff into your truck. The band snaps with a POP. On my lumbermate, it always ends up about half out of the little blade cover void where sawdust exits as I cut. NEVER let anyone stand in front of your mill or near the sawdust exit shoot as you cut. BE CAREFUL!

bandmiller2 · « **Reply #2 on:** July 27, 2010, 07:27:52 pm »

You may need a skivie change,its a loud bang.You never really get used to it,sometimes you can hear a ticking just before or a shudder but usally a big surprise.Frank C.

Jeff · « **Reply #3 on:** July 27, 2010, 07:47:29 pm »

I would say unpredictable is correct on predicting what will happen when one breaks, but a well guarded commercially built mill puts the risks at a minimum as long as you stay out of obvious danger zones such as under the sawdust chute.

stormyweatherman · « **Reply #4 on:** July 27, 2010, 07:57:12 pm »

watching that blade going around and ripping through logs, it has become a more important question in my mind of late. just want to saw as safe as possible. thanks again guys.

Bibbyman · « **Reply #5 on:** July 27, 2010, 08:06:20 pm »

It depends on where and when the blade breaks. If it breaks while cutting wood and the break is somewhere in the upper part of the housing, then there is a loud pop, the blade stops and not much else happens.

If the blade breaks while not sawing, it can be quite a bit more eventful as there is nothing to slow down and contain the blade. It will often accordion up in the dust chute or against the outer guide roller. Usually the blade will be contained in the housing. Often in more than a couple of pieces.

Sometimes the break is while not sawing and it happens to break somewhere between the guides. In that case, the blade can come out of the housing a good little bit.

We’ve had hundreds of blades break and I don’t remember a time I didn’t jump. You can get a clue if you start hearing a “click”, “click”, “click” sound. That’s the sound of a crack forming. A break won’t be long after.

Two strong suggestions; One, never remove the “grizzlies” from the dust chute. I know they’re a pain in the butt and cause you to have to pull a bird’s next out of the chute once in a while but they will stop a blade from coming out the chute. Two, never put your hand in the chute while the blade is turning to pull out a clog or for any other reason. You never know when a blade may break, even if brand new, and you’ll pull back a bloody stub.

Here are a couple of pictures of blade breaks.

Oh yea, one last tip.. When you get a band that breaks in the log, it’s often hard to get it out. Some drive a wedge of some kind in the cut to open it up so the blade can be slid out. But I have an angle head grinder that I use to just cut the blade on each side of the log. The head can be brought back and the broken blade dealt with. The part stuck in the log can usually be pulled out by hand or by the use of some channel locks.

bandmiller2 · « **Reply #6 on:** July 27, 2010, 08:20:43 pm »

Outher than the danger to operator and offbearer quite often the broken band will take a chunk out of your bandwheel belt.Its good form to check bands in good light if hairline cracks are found throw it out before it breaks on you.

stormyweatherman · « **Reply #7 on:** July 27, 2010, 08:31:02 pm »

thanks for the pics bibbyman and warnings from others too. its a little daunting thinking about that blade coming at me. i showed the pics to my offbearer too. i stop the blade after every cut and i know to stay away from the side, the front and the chute. also noticed recently cutting spruce that the chute builds up a lot of dust etc. using more water for the spruce. but its still been on my mind.

Bibbyman · « **Reply #8 on:** July 27, 2010, 08:47:38 pm »

Keep in mind that the pictures shown are the most eventful break we've had out of maybe over a 1,000 blade breaks. Most are quite safe although alarming. We run our blades to death. I'd say 50% die by breaking.

I may mention removing a broken blade can be a little dangerous. They tend to be spring loaded sometimes or twisted around things. Heavy leather gloves and sometime heavy channel locks will save you from getting “bit” by a blade.

Kcwoodbutcher · « **Reply #9 on:** July 27, 2010, 10:26:08 pm »

One more thing. When the blade breaks the idle wheel will spin for a minute or two. Don't open the guard until it stops. It can grab the blade and send it flying.

paul case · « **Reply #10 on:** July 27, 2010, 10:31:39 pm »

stormy,
watch that blade. when the blade forms a crack in the gullet,which is where it usually happens, you can see it move foreward on the guides. i broke a few when i first started then i started to payin attention and have took them off when they crack ever since.i dont shut the blade off after each cut since i usually cut serveral boards or a whole cant into boards before offloading.this is when i usually see the blade moving badly. the cracks in blades sometimes cause a different cut pattern on the wood too. the blades breaking while running can cause damage to the sawyer for sure but also to the mill. the belts on the wheels and drive belts can be damaged or ruined by a broken band so i try to avoid letting them break on the saw.pc

redbeard · « **Reply #11 on:** July 28, 2010, 12:07:42 am »

I always check my used or re-sharpened blades by bending them in a tight radius up close and the cracks will show up real easy you will also be able to feel and detect soft and brittle metal. When you know your pushing your blade to much is when they start getting dull when the saw dust starts turning into spaghetti gets real stringy. Time to change them.

kelLOGg · « **Reply #12 on:** July 28, 2010, 05:03:53 am »

All my breaks have been while not actually cutting and have been single breaks, except for one. For the exception, I noticed the band oscillating forward and back on the roller guides akin to Paul Case describes. I had never seen that before and seconds later the usual loud POP. The blade broke in two places with one piece only a foot long. Being so short it could have flown unpredictably but was well contained. Having crowned steel wheels I don't have a drive tire to be damaged.
Bob

paul case · « **Reply #13 on:** July 28, 2010, 06:13:00 pm »

ok stormy i got it.
you can expect to jump, spend a few minutes cleaning your britches? and puttin a new blade on. pc

terrifictimbersllc · « **Reply #14 on:** July 28, 2010, 06:32:20 pm »

As "it is appointed to a man once to die.....", it is also appointed to a blade once to break. With one exception (below) it hasn't spectacular for me maybe because I always wear hearing protectors, so my clothing has remained clean. Usually the customer is at the far end of the mill and gets more excited.

Just want to add 2 things, carry a metal snips with you and you'll get the broken blade out quicker.

The other thing is something I'll never forget and is the reason I usually put up traffic cones to mark a danger area off the drive side of the mill when the engine is revved..."never within 20 feet of a 45 degree cone coming out of the exit chute" I say but shutting down the blade when someone is too close is really the only truly effective action. Once in my first year of mill ownership I was edging a board and near the end of the cut the blade shredded. Probably was a new blade. I only figured out what happened when I walked around picking up pieces of the blade, ribbons and shreds, which shot out at least 30 feet over a wide angle. I don't know if it went through the chute or what. But anyone close could have been severely injured and I am grateful for the free lesson.

Bibbyman · « **Reply #15 on:** July 28, 2010, 07:42:46 pm »

Here is an 8" section of the blade I posted pictures of above. This is where I found it. I'd say 99% of blade breaks are fully contained in the shielding. Most break only in one place.

pineywoods · « **Reply #16 on:** July 28, 2010, 07:55:21 pm »

Just keep in mind that at normal cuttin speed, that blade is traveling 50 to 60 miles per hour. Treat the dust chute area the same as you would treat a loaded gun...Someshere I have some pics of a broken blade that broke off one of the grizzlies and then punched a hole completely through a meta dust chute.

Kansas · « **Reply #17 on:** July 28, 2010, 09:06:45 pm »

Pretty well what everyone has said is correct. Keep a clear zone on the discharge side of the chute. Keep people away from the front of the mill, especially if you start to hear that clicking noise. Had a blade on the woodmizer break apart a few weeks ago and shot out front about 15 feet. Most of the time, its not a big deal.
The worst one I ever saw was on our other mill. A blade broke into about 4 chunks. One shot up and buried itself in the tin roof. About 8 inches was sticking through the roof out of a 2 foot chunk. I was going to take a picture of it. Decided it might be better to get it down from there and not have any incriminating evidence in case the government showed up.

Brucer · « **Reply #18 on:** July 28, 2010, 10:20:01 pm »

First time I broke a blade while I was set up at the timber framing shop, all the workers jumped and stared at me. I took off the muffs and said, "What's the deal, it's just a broken blade?" I wear were shooter's muffs and they're designed to really damp down the loud bang you get from a gun -- or a broken blade

.

I've never heard one break while not wearing muffs, so I can only go by how other people react.

I've only broken a hundred or so, so I haven't experienced everything that Bibbyman has. The latest "unusual" break was a blade that hit the fingers and then curled upward and back toward the band wheel. That was "interesting" to remove.

carykong · « **Reply #19 on:** July 28, 2010, 10:45:47 pm »

NIce aspect to LT 10 is that horsepower is relatively low. You will experience far fewer blade breaks than LT 40 types that operate with a lot more horsepower to the blade and faster feed rates. Your blades will dull and simply stop cutting before they break. I have an LT 25 with 15 horsepower,single cylinder Kohler, owned my mill for 11 years. Yup, I break a few blades but I usually have to change the blade first due to dullness.

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Author Topic: what to expect when a blade breaks? (Read 1529 times)