Hey Jay, what have you got against lathes?

So I am a machinist at a company that makes... big stuff. I program and run mills. I refuse to do lathe work.

This happened about an hour ago. A hardened chromed 3 inch shaft decided to bend on the tail end, flinging it's support across the shop before beating the lathe to death.

The operator was unharmed.

This was the 9th of these shafts run today, with no problems and not the first time we've run them. 

during it's death throes the machine managed to walk off of it's pads.

So... super fun.

Keep your wits about you. Complacency kills.

Root cause for shaft bending?

I bet that's a hell of a video!

I was in the shop when a guy crashed a turret lathe so hard the turret broke off. It was terrifying. Lots of energy in these things. 

We're thinking improper heat treating leaving a softer spot. *shrug*

It's not an abnormally sketchy setup. These parts are done pretty frequently.

The tail end was riding in a support stand like this one.

I pulled rank as the safety guy and sent to operator home. Not as a punishment but after that, I wasn't ready to stick him on another lathe. Go home, relax, we'll see you tomorrow.

AClockworkGarage said:

We're thinking improper heat treating leaving a softer spot. *shrug*

 

It's not an abnormally sketchy setup. These parts are done pretty frequently.

The tail end was riding in a support stand like this one.

I pulled rank as the safety guy and sent to operator home. Not as a punishment but after that, I wasn't ready to stick him on another lathe. Go home, relax, we'll see you tomorrow.

Good call.  Let him get the willies out of his system away from heavy equipment. 

I hate when I only get 30 seconds to pause and catch myself after an incident.  Leaves my brain fried for so much longer

Glad no one got hurt...  And good call sending him home to catch his thoughts!

As someone who programs and occasionally runs 5-8 axis machines, I try to avoid lathe work as much as possible.  I understand kinetic energy and those things scare me..

That said, I just bought a little 9" south bend for home :)

Wow, glad nobody was hurt! Were all 9 shafts the same length thru the tailstock? It's curious that only 1 decided to go caddywompus. I suggest running a quick critical speed hand calc or modal analysis on the shaft and setup before running that job again. Slight changes in length or RPM can put you in a mode where things get wild.

​

I've done some sketchy stuff with material hanging out the back of the headstock. Nothing like that kind of mass though.

Glad everyone is ok. Only bad stuff happens quickly.

AngryCorvair (Forum Supporter) said:

Root cause for shaft bending?

Ha. "Root"..."shaft"

glad nobody got hurt. 

I had an incident last week where a staging platform collapsed and injured 2 of us. I've got a broken rib and a lot of bruises and lacerations- the other guy is much worse. 
 

Yes, I absolutely pulled rank. Sent everyone home.  Even the people who were not involved got to watch a guy get thrown 45' down a stairway into a concrete wall. 
 

It happened because of a lack of mental alertness. After that, no one had mental focus. No amount of productivity mattered after that.  
 

We will be ok. But people's mental and emotional well being is every bit as important to me as their physical well being. 
 

In reply to SV reX :

Sorry to hear that happened, but glad to hear you're going to be ok. Hopefully the other guy is too.

In reply to Driven5 :

He'll be ok, but he's out of commission for a couple months. 

Please don't blame the lathe, they're just big dumb pieces of metal, machined and assembled to perform a task.   

My neighbor used to work in a shop that had a lathe with, iirc, a 48" chuck. Used to.  He has a couple interesting stories about the Big Lathe...

My buddy worked for machine shop that previously had a contract for some portion of the machining of aircraft carrier prop shafts. They no longer had that contract and needed to scrap the lathe that they'd used for that work (it took up some serious floor space). Took cranes and a slew of riggers to break it down into chunks small enough and light enough to load flatbed tractor trailers and it took 2 days worth of loading it out on said tractor trailers to get it all gone. And that was two cranes outside the machine shop. They'd used the machine shops gantry cranes to do some portion of the work to get it "out".

I was there one day picking up significantly smaller lathes and mills around the time they were trying to scrap that huge lathe and we actually had the conversation about how nervous it would have made both of us to be anywhere near the hunk of metal spinning in that big thing back in the day, but an old crusty machinist who'd been a part of the job 'way back when' essentially called us sissies. 

In reply to Spearfishin :

...as he pointed at us with one of his seven remaining fingers.

Appleseed said:

In reply to Spearfishin :

...as he pointed at us with one of his seven remaining fingers.

Haha, exactly. 

Recently bought an old 10" atlas, my wife made some comment about teaching my kids to use it in a few years. Uh, more than a few sweetie...  

I think this is our biggest lathe.

I think its like a 40 inch chuck with like 20 foot ways. We don't use it often.

One of our Horizontal mills is, apparently, the largest on the west coast. It has an elevator.

We build machines for lumber prep. We ship about 2 a year. Each machine leaves on about 25 semi trailers. Big stuff.

My point in making this post isn't look at this neat/terrible thing happened. It's that safety is everyone's job. There are a lot of people with 7 fingers who will call you a Bob Costas for caring about safety but the facts are

1. Your job does not care about you.

2. They do not pay you enough to get hurt.

3. Your position will be posted before your obituary is.

Be safe, put your 40 in, go home and live your life.

Gee, we get all bars cut into 3' sections for this very reason. No bar sticks out of the machine, there is no point. 

I worked with a old machinist years ago. He refused to operate spinning lathes. 

In reply to TJL (Forum Supporter) :

Hard to get any work done if they're not spinning. 

I like my tools spinning, not my parts.

We have Fermat boring mills like that. It's a days work for me when they crash one. 
 

I love lathe work.