# Bandsaw blade explodes



## SE18 (Feb 21, 2008)

Shortly after this photo was taken (actually a cropped area of a photo I took displaying some woodwork I was doing), my bandsaw exploded with a loud noise as a chunk of wood was sucked down this hole. The blade snapped off in 2 places. 

Fortunately, the machine still works and the cover prevented the blade from injuring me.

Is there supposed to be some sort of covering on this hole? It didn't come with one. This explosion is sometimes also what happens on my large table saw. I mostly solved the problem with the table saw by building a cover. Is this the sort of solution that needs to be done on a bandsaw?


Thanks in advance.


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## Semper Vaporo (Jan 2, 2008)

Your "Before" photo didn't show up. Need an "After" photo too. I don't understand your term "Explode" in connection with a bandsaw. I assume you mean the blade grabbed the work piece, bent, then broke, tossing blade and work piece chunks around. Did it damage the wheel covers or safety devices? 

If you need help posting the photo, ask.


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## SE18 (Feb 21, 2008)

Sorry, forgot to post photo. The "explosion" is what it sounded like when the wood chunk hurled into the bandsaw. Nothing was damaged except the blade, 2 clean cuts produced a 3 inch blade and a longer 56.5 inch blade, blade not damaged other than being cut like that


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## Duncan (Jan 2, 2008)

You can make a closer tolerance cover to replace that blue thing... 
However, you need to make sure that you're leaving room for roller and blade tracking adjustments... 
I'm guessing that you have a three wheeled bench top sort of bandsaw that has limited capacity?? 
I occasionally have little chunks of scrap drop through the plate on my 12" Craftsman, making that same sort of loud noise as the chunk-o-wood gets bounced around at high(ish) speeds amongst the drive wheel and the saw housing. 
Never blew up a blade (yet)...


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## wchasr (Jan 2, 2008)

Tough to tell how big an opening that is based on that photo But it seems it is bigger than need be. Having a little experience on band saws sheet metal cutting at a former employer and wood cutting any where else. I've never broken a blade cutting wood but would often break blades at work. I never got to the point where I could repair them but someone was alwys around who could do it for me. I'd make or get a new insert to reduce that hole size though. 

Chas


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## Mike Reilley (Jan 2, 2008)

I've broken a bandsaw blade before. I think what happens is that the little piece of wood or metal that falls down the hole gets between the band and the lower wheel drive wheel. That apparently puts a crimp in the blade where it fails/breaks...especially if you have it tensioned pretty tight. Best advice is to keep the gap in the cover plate as small as possible.


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## SE18 (Feb 21, 2008)

thanks; which leads to the next question:

how do you know when the tightness is correct?


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## Les (Feb 11, 2008)

SE,

You're going to think I'm yanking your chain, but I use the 'guitar string' method: twang it with my finger and listen for the sound. After awhile you can tell by the sound about how tight it is. Used this method on the big 7' Grob at work, on both my wood bandsaws, and my power hacksaw. It does work. The idea is, you don't want it any tighter than necessary to stay on the wheels and well aligned.

I'd urge you to cover that hole. Sometimes it's called a 'throat plate'. Make the width of the slot the same as your sawblade, it'll 'waller out' after a little use and have just the right amount of clearance. You do want to make sure your blade adjustments are all done, before you do this.

Oh, you go where there's the longest uninterrupted length of saw blade, that's usually from the back of the bottom pulley to the top of the front. Which means you have to take the cover plate off.

Hope this helps.

Les


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## SE18 (Feb 21, 2008)

Thanks, Les (again)


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## Torby (Jan 2, 2008)

And they do break now and then. Rather frightening when you're from electronics and you're borrowing the mechanics' humoungous band saw and the blade breaks. They thought is was pretty funny to see the sparky jump out of his skin. 

"I'll put a new blade in. Come back after lunch." 

The fresh blade was MUCH easier to use.


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## Les (Feb 11, 2008)

Torby,

Heh, heh. Would you like some possible insight into their thinking? Maybe something like this:

Joe: "We gotta change out that big blade. Dull. Gonna let go pretty soon. It shed some teeth awhile ago."

Sam: "Yeah, I heard that. Ain't that bad, yet. Quite a few teeth left."

J: "Let's get 'er done."

S: "Aww, mannnn, like, that's a lotta work. That blade's more'n 10 feet long. Let's leave it for second shift."

J: "Ain't no second shift. Get the the blade stock out--whoa, look who just walked in!"

(Knowing glances exchanged.)

Torby: "Hi, ho, Fellows! Can I do a few cuts on the big saw?"

J & S: "Why, oh heck yeah! Go right on ahead, she's ready."

(Sound of bandsaw spinning up, sound of metal being fed in--*BANG!--* Sound of muffled shriek.)

T: "Aw, I broke the blade!"

J: "Ah, come back after lunch.... it's okay. Everybody screws up now 'n again."


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## Torby (Jan 2, 2008)

There was some snickering









It had been missing a few teeth for a long time. Was much better with a new blade.


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## Les (Feb 11, 2008)

Where do you get your emoticons?


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## Torby (Jan 2, 2008)

I have quite a collection I've gathered. Quite a lot came from Yahoo Instant Messenger. 

If I recall, when the blade broke there was a huge BANG noise and the blade just disappeared. The mechanics were able to stuff the skinny sparky back into his skin.


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## Les (Feb 11, 2008)

Torb,

I don't know beans about emoticons or how even to stick 'em into posts. Or where to put 'em until you need 'em. I don't know much about nothin' comes to computers, that's what my kids are good for. But they're always busy.

I loathe Yahoo, FWIW. Suckers hijacked my homepage and it cost me $40 to get it back. Also, ATT. Wrote the Att. Gen. of MO, got a 'Vote for me!" letter in return mail, took about 6 more weeks before some s.o.b. answered my letter wtih, essentially, "Sucks to be you."

Sometimes, it does.









Les


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## work4fil (Jan 4, 2008)

Back in my sawmill days, we would lose one of the band mills occasionally. We heard a story one time of a head rig that broke its abnd saw cutting a big fir log. The saw wrapped itself around the bottom wheel down in what was called the "**** hole." Curiously the crew gathered around to peer down into the bottom wheel while the sawyer wond down the wheels. The broken saw decided it had enough of riding around the bottom wheel came flying out like a coiled spring. People scattered like crazy as the saw came out and ran around the mill floor. Fortunately no one was hurt, though some pants were stained.

Later after this story had made its rounds, were cutting second growth pine in our quad mill, when one of the logs broke in the carriage. One saw backed off the mill and ran itself into the housing and the other three saws broke into pieces flying around the mill. Again we were lucky, nobody got hurt, though the cant sorter got chased by flying saw pieces. Thise were the days.


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## Les (Feb 11, 2008)

I never worked in a sawmill, just hauled logs in either to sell or for lumber for my buildings. (Or both.) I was cutting over 400 acres of second/third growth. Wore out or ruined 4 McCollough's when they were the saw to own. Now, they're crap. This sawmill, ca 1966, that I hauled to was a 4 ft (?) circular saw run by a 4 cyl International stationary. Also, worth noting, it hadn't changed much since the '50s, when son took over from father. One day I'm going to model it for my RR.

I've never seen a bandsaw mill, I understand they're popular out west or in the tall timber. (My g.father was a topper in the 30s in Washington state.)

When you're working with machines that are moving seriously fast in feet/min (I forget the correct terminology--ah, surface ft/min) when something goes 'bang', a good plan is to either hit the deck or go away until everything's quiet. Not crowd around to see who got his. But guys who work in sawmills don't have a lot of imagination, sometimes. (I'm cursed with overmuch, which is prob'ly why I've got all my body parts.) Nerves ain't much, tho.









Appreciated your post, info like that tends to accumulate. And the cant guy, gotta feel for him, y'know?

Les


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## SE18 (Feb 21, 2008)

Les, 

That was great advice about the twang sound of the guitar. Sure enough, you get different pitches as you tighten. Advice not found in owner's manuals. 

I'm on my way to becoming an expert sawyer. 

And great stories, all.


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## Torby (Jan 2, 2008)

The question, of course, is which octive should you tune it to?


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## Duncan (Jan 2, 2008)

Posted By Torby on 03/12/2009 7:20 AM
The question, of course, is which octive should you tune it to?


"B Sharp", of course...


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## SE18 (Feb 21, 2008)

Twanging a loose blade has an off note or off pitch. Just a little bit of tightening and the pitch or frequency goes up and it just sounds right to my tin ear.


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## Les (Feb 11, 2008)

Posted By Duncan on 03/12/2009 8:29 AM
Posted By Torby on 03/12/2009 7:20 AM
The question, of course, is which octive should you tune it to?


"B Sharp", of course...
















Duncan,

That was _painful, _man. Painful. But funny.

Les


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## Duncan (Jan 2, 2008)

Les, 
We aims to please, no matter HOW much it hurts...


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