Is this common ???

[KD57]

Flying metal chunk just a machine part
The Associated Press


DALLAS -- Police say the 6-pound chunk of metal that fell from the sky and through the roof of a Dallas home was part of a machine used to grind up trees.

"Mystery solved," Dallas Police Sgt. Gil Cerda said Friday. "It's not part of a satellite or part of a rocket that lost a tire or something. This was nothing more than part of a mulching machine."

The chunk that smashed a baseball-size hole in the roof and the second floor of the home Tuesday night didn't hurt anyone, but it puzzled investigators. Radioactive tests were negative. Several state agencies were notified, but none offered a theory about what happened.

"We were all like, 'What is this thing? Did it come from space?' " Cerda said.

The tree-mulching machine theory gained traction throughout the week, and Cerda said officers finally confirmed with a nearby tree-disposal service that it was a carbide grinding tip that flew off a machine. The house it hit was 900feet away.

Dallas Police Senior Cpl. Janice Crowther said no charges will be filed against the business because it was an accident.

Last week, an 8-pound chunk of metal crashed through the roof of a warehouse in Jersey City, N.J., sparking theories that the object was satellite debris before police determined it had flown off a large mulching machine.

 

[tomtrees58]

yep that's a tub grinder four you tom trees

 

[ASD]

If you do not keep a tub grinder plugged full at all times this type of thing will and dose happen all to often as the high speed of the head is pointing straight up with nothing covering it and if a tooth comes off they will fly real far

 

[fourfivefour]

I remember seeing that story and when they showed the object I knew exactly what it was. Space junk! LOL It was an insert from a tub grinder.
I have 10 years experience working on a Morbark 1200XL tub grinder. The 1200xl uses a 2lb insert (chipper blade) on a 20 lb hammer. There are 24 hammers on the mill. Morbark makes larger tub grinders with 100 lb hammers with larger inserts.
My guess is:
They were probably running the tub without the deflector on the mill. It will grind faster without it, but will throw $hit hundreds of feet in the air when the tub empties out. With the deflector in place it drastically cuts down on flying debris. Morbark sells a steel cap to put on the tub for grinding in delicate surroundings.


Here is a video of a Morbark 1100, very similar to the 1200xl I work on. If you've never seen a tub operate check it out, they are very impressive.
http://www.youtube.com/watch?v=rJjvBw4ATq0&feature=related