Close, But No Cigar

[Bruce Cohen]

I've been building a desk for my daughter and the plans called for maple veneer plywood. I was getting splintering with my Freud 80 Crosscut blade, so , of course, I "just had to get" their LU80R010 10" 80T HI-ATB BLADE "ultimate plywood blade" . It works like a charm, no splintering no matter which side you feed the stock into the blade.

Well today, as I'm cutting more ply, I feel something akin to a close range shot from a pellet gun on my right chest. No blood, no bruse, but a good size piece of one of the teeth broke off from this new blade and is sticking into my sweatshirt.

Never had that happen before! It's a pretty scary feeling. Even though I was wearing safety glasses, which I always use, my face wasn't affected. Still, glad I did have my glassed on as I started to picture this piece of carbide tooth stuck into my eye and not my sweatshirt.

Monday, I'll call Freud and "give them h**l". The blade does come with a lifetime warrantee.

The moral of the story is Always Wear Safety Glasses and Kevlar body armor.

Bruce

[kwgeorge]

WOW! That sucks! I worry about that with cheap router bits and such. Did you check the ply to see if it had something embedded in it that caused the issue? If not I would really give them a call on this as it could have been a lot worse.

Ken

[scmhogg]

Bruce,

I had a similar thing happen the first time I used a new Oldham blade that I bought at a show. Also with plywood. There was nothing I could find in the wood to cause it. But, I couldn't find the tooth either. The noise was the tip.

I sent the blade back with a note explaining what happened. In a few days I received a new blade, with a carrier and an extra blade as their apology.

Steve

[JSCOOK]

Glad to hear you weren't hurt ... I'd call that scary in deed ... I'm glad that most times in the shop I actually wear my clear grinding face shield instead of glasses.

[zintk]

Thanks for the safety example. It goes to show that anything can happen, usually unexpected!

[Stytooner]

Shark? .

[Bruce Cohen]

Hey Lee.

You're 100% right, I had the Shark off the saw at the time. That would have stopped the "flying tooth" completely.

So even though I was wearing glasses, the Shark would have done the job. Luckely, I got hit in the chest and not the face.

I will now write "I will always use my Shark" 1000 times on the wall of my shop.

Bruce

Oh, BTW have a great holiday, if I don't get to talk with you before year's end.

[Pappy]

Considering the velocity it would have left the blade, I'd say you were very lucky. I'm guessing the point of impact was at an angle and not straight on or it would have penetrated.

[Turaj]

Wow! Bruce count your blessing as you have been very lucky indeed! I have heard of similiar stories but with much worse ending Glad you are fine and thanks for the remider.

[TheRic]

Ouch, that hurts thinking about it!! You definitely can count your blessings on what could have happened.

[LCHIEN]

Considering the velocity it would have left the blade, I'd say you were very lucky. I'm guessing the point of impact was at an angle and not straight on or it would have penetrated.

the effect of a projectile has to do a lot with its mass, impact area, and especially the velocity, since the energy of a projectile is proportional the mass times the velocity squared.

The velocity of the tip of a 10" saw blade turning 5000 RPM is 150 mph or 200 feet per second (FPS).

The velocity of a bullet is around 900-2000 FPS, .22 caliber LR are 1100-1300 FPS (Wikipedia). Or on the order of 10X the speed of the blade tip.

I would estimate a carbide tip to be less than 1/10th the mass of a .22 bullet, esp. since the bullet made of lead is much denser than the carbide.

Therefore the energy packed by the carbide tip would be 1/1000th of the energy of a .22 caliber bullet. So a sweatshirt would be enough protection but I would be glad of wearing safety glasses.

Now, a kick-backed square of wood like 4" x 4" X 1/2" thick would easily weigh about 10 times a bullet, probably more, and be coming off the saw with similar velocity to a carbide tip (probably slower since a big fraction of the energy will be rotational rather than linear). So its energy might be 1/10th that of a .22 bullet. In that case, a sweatshirt would not be much protection, you'd probably get a bruise. But, no bullet holes, since the impact area will be quite a bit larger and cause less local damage but over a wider area.

[Bruce Cohen]

Accident Update

This morning I looked in the mirror and noticed a bruse the size of a quarter with a tiny break in the skin in the center of the bruse where the broken tooth hit me.

So I guess it (the chipped tooth) did have enough velocity to penetrate a sweatshirt. I don't know what that translates into in feet per second, but I'd rather not do it again to test it out.

I'm going to order one of those leather aprons that I've seen on-line. They're not cheap, but they're a whole lot less than a Kevlar vest.

Bruce

[wardprobst]

This morning I looked in the mirror and noticed a bruse the size of a quarter with a tiny break in the skin in the center of the bruse where the broken tooth hit me.

So I guess it (the chipped tooth) did have enough velocity to penetrate a sweatshirt. I don't know what that translates into in feet per second, but I'd rather not do it again to test it out.

I'm going to order one of those leather aprons that I've seen on-line. They're not cheap, but they're a whole lot less than a Kevlar vest.

Bruce

Bruce,
Thanks for posting this wake up call. I am becoming more safety conscious every day. I worked in a furniture shop in Houston in the early 70's where I learned a lot of bad habits and have been relearning ever since. After I quit, OSHA stopped by one day and hit them with 33 violations and my buddy that was still working there said they didn't even see the bad stuff.
Point- it's so easy to forget to use safety devices especially if you don't spend every day in the shop and sometimes even if you do.
The shark push stick saved my fingers a while back and as a pianist, I'm grateful. Another friend wasn't so lucky.
Be safe,
DP

[cabinetman]

Bruce

Maybe a bullet proof vest. I've had many teeth fly off, and you don't find out right away. Most of the time if you are hit it feels like a sting. The blades don't have to be cheap ones either. Usually, the tooth will dislodge after it makes contact with the stock and will end up under the saw. I don't always find the carbide.



"I'M NEVER WRONG - BUT I'M NOT ALWAYS RIGHT"