Eventful blade break.

Bibbyman · October 06, 2006, 05:51:49 PM

We've sawn somewhere around two million board feet on three Wood-Mizer mills. One thing I really appreciate is how safe the mill is designed. It has the best blade housing shielding I've seen on any bandmill. And I've seen good, even as good, shielding on other major brand bandmills.

But you can't be too careful. Today we had one of the most eventful band breaks we've ever had.

Here is a 8" section of blade on the ground under the dust chute. I'm not sure where it ejected from but I'm glad it didn't go any further.

Here is the section of the blade that is sticking out of the back side of the saw head.

This is why we keep the shielding on, grizzlies intact, and never stick our hands in the dust chute while the blade is turning.

logwalker · October 06, 2006, 08:40:49 PM

That is amazing. I can't see how that sucker got that far out. Were you in a small or big log, Bibby? Who was running the mill? Lw

ElectricAl · October 06, 2006, 09:10:33 PM

I must agree with Bibbyman on the safety of our Wood Mizer. We also have sawn over 2 million feet with our Wood Mizer, and braking blades is a regular occurrence. However on occasion out they come.

This is our collection of "Eventful Blade Break"s.

This one got past whats left of our factory saftey guard. Years of blades smashing into the guard has taken a toll.

The cant pulled out of the clamp and broke the blade. I was sawing extremely fast and put too much side load on the cant.

Now we're spending money :-\

This one was good for 30 minutes of down time :

But if you're going to break something, break it good. ;D

Then take a picture and share it ;)

Bibbyman · October 06, 2006, 09:20:39 PM

Quote from: logwalker on October 06, 2006, 08:40:49 PM
That is amazing. I can't see how that sucker got that far out. Were you in a small or big log, Bibby? Who was running the mill? Lw

We were sawing out 6x6s out of 10" oak logs. But the blade hadn't made it to the log when it broke. Had it been in the log, it well may have been contained. But we've had some break while sawing and still thread out some here or there.

I was sawing and Mary was offbearing.

I couldn't imagine where all this sharp blade would have went had there not been shielding to take most of the fight out of it.

Tom · October 06, 2006, 09:27:58 PM

I never broke a blade.

Isaiah

ElectricAl · October 06, 2006, 09:35:12 PM

If it ain't broke, you ain't trying ;)

Red Green :D

Percy · October 06, 2006, 10:09:14 PM

WOW Bibby,

Scary stuff. Since I switched to the WM CBN grinding system, blade breakage is almost non exsistant...BUT..... yesterday I had and old narrow one break when it was spinning full tilt but hadnt entered the cut yet. In my 9 years of operatin WM's, I never hadda blade break that wasnt cutting, till then. The results wernt as spectacular as what you have shown but adrenaline was free for the taking.... ;D ;D ;D ;D

Brucer · October 07, 2006, 02:21:09 AM

When I was sawing for Louis two years ago, I put a couple of hundred hours on his machine. Then I put 150 hours on my manual machine, and another 200 hours on my new hydraulic mill. Not once did I have a broken blade try to go out the chute. Then, in one week, I had three blades bang into the blade catcher fingers.

The first was the scariest one -- the blade broke in two places (I'd never have thought that could happen) and a 3 foot chunk tried to take flight. I actually felt it hit the blade catcher. I figure the folks at WM had a good reason for beefing up those fingers in recent years.

I kept that piece of blade and now it makes a good show-and-tell demo. Customer gets careless about walking past the chute when the saw is running, I just hold up that piece of blade and tell them to imagine it flying toward them at 100 km/hour (at waist level). Tends to get their attention ;D.

D._Frederick · October 07, 2006, 02:30:59 PM

How much run time are you getting on the blades that break? Are they flex back or harden back blades that are breaking?

Bibbyman · October 07, 2006, 03:55:31 PM

Quote from: D._Frederick on October 07, 2006, 02:30:59 PM
How much run time are you getting on the blades that break? Are they flex back or harden back blades that are breaking?

I'm not familiar with "flex back" or "hard back". I'm using Wood-Mizer Double Hard .055x1.25 wide.

This happened to be a new blade and we'd sawed less than 1,000 bf of oak with it. I've got some problem with blade breakage lately. I've changed and checked about everything but the roller guides. They're next.

But the problem is not the blade. Blades will eventually break.

PawNature · October 07, 2006, 04:25:31 PM

If it ain't broke, you ain't trying

Red Green

I don't care if he is Canadian, I love Red Green.

Percy · October 07, 2006, 05:35:25 PM

Quote from: PawNature on October 07, 2006, 04:25:31 PM
If it ain't broke, you ain't trying

Red Green

I don't care if he is Canadian, I love Red Green.

Im glad you like Red Green, even if you are an American. ;D

Larry · October 07, 2006, 05:41:48 PM

Quote from: ElectricAl on October 06, 2006, 09:35:12 PM
If it ain't broke, you ain't trying ;)

Red Green :D

Or my favorite

If it ain't broke, it's fixin to break. :

DanG · October 07, 2006, 11:34:00 PM

Me and another Forum member was flappin' our lips at one another on the phone a couple of weeks ago. He was telling me about the guy that sharpens his blades for him. He says that he said that you need to clean out the gullet with each sharpening, to remove the miniscule cracks that develop there, so that they won't spread into the body of the blade and cause breakage. Is your blade sharpener doing this? If not, it may be worth looking into.

Radar67 · October 07, 2006, 11:36:30 PM

Bibby, I've never had a blade break until today...I do believe you jinxed me with this post! :D :D :D

Stew

Bibbyman · October 08, 2006, 04:06:48 AM

Quote from: DanG on October 07, 2006, 11:34:00 PM
Me and another Forum member was flappin' our lips at one another on the phone a couple of weeks ago. He was telling me about the guy that sharpens his blades for him. He says that he said that you need to clean out the gullet with each sharpening, to remove the miniscule cracks that develop there, so that they won't spread into the body of the blade and cause breakage. Is your blade sharpener doing this? If not, it may be worth looking into.

Very true.... But this happened to be a new blade out of the box.

The point of this post is - blades do break and they do jump off - and when they do, they have a lot of speed and force behind them that could cause a lot of damage or injury. Thus shielding, grizzlies and caution is important to maintian life and limb.

jpad_mi · October 08, 2006, 08:13:12 AM

Thanks for this post Bibbyman. It's a good reminder for the experienced and a good lesson for the newbies like myself. I have a couple of questions though...what the heck are grizzlies? And does anyone have a picture of the WM blade catcher fingers that Brucer mentioned?

VA-Sawyer · October 08, 2006, 07:08:41 PM

I believe that "grizzlies" is just another name for the "blade catcher fingers" that are located in the sawdust exhaust chute. Sorry I don't have a picture.
VA-Sawyer

Bibbyman · October 08, 2006, 08:50:49 PM

I knowed I had a good picture of the grizzlies in the dust chute of our Wood-Mizer. The grizzlies are those three vertical bars. Behind them you can see a blade that has been retained by them.

When I found the picture, I also found a I'd posted something like this before.

Here is a link to that older thread.=> What happens when a band breaks.