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Can you have some of the material sticking out of back of cnc lathe?

So I decided to forego the stickout. Well in a way. I had been cutting off about 3 inches of material with the cutoff tool and just realized that I had a 2 inch stickout anyway. It would now be about a 6 inch stickout and after testing it, it seemed fine but I didn't really like the noise it was making. I am sure it's the new liner doing its job but I would rather just be safer and continue to do it the way I was before. The good news is now there is no more crappy finish when I put a new bar in!
You are dealing with several things at once, the only one that maters is ; Is the stock in the spindle causing my machine to act funny , if so it is not running true enough and possibly your collets are not closing tight enough. The brass is heavy so run out really counts.
Now that I know your part length I change my bushing recommendation to snug fit on bar with set screws and close slip fit down the bare spindle. I think you said you have a sleeve stuck in the spindle, I would fix that it will be an on going limiting factor to running.
 
I had a guy die, literally in my arms laying on the ground after getting hit by a bar sticking "just 18" out the back of the lathe. This was 17-4 SS, 1" dia. It bent it just like that picture up there, little more than 45 degrees. I think that was limited to 3600rpm

Pummeled the guy. Morcellated his esophagus and arteries, but never broke the skin.

Dead.

Be very damn careful sticking anything out the back of the spindle. Speed up to 5000 RPM and you can snap a 1/2" hanging out 8 inches.
Shit get's crazy and it is just safer to keep it contained.
How about a sawzall to cut the bars up if it's only a one time thing?
 
I had a guy die, literally in my arms laying on the ground after getting hit by a bar sticking "just 18" out the back of the lathe. This was 17-4 SS, 1" dia. It bent it just like that picture up there, little more than 45 degrees. I think that was limited to 3600rpm

Pummeled the guy. Morcellated his esophagus and arteries, but never broke the skin.

Dead.

Be very damn careful sticking anything out the back of the spindle. Speed up to 5000 RPM and you can snap a 1/2" hanging out 8 inches.
Shit get's crazy and it is just safer to keep it contained.
How about a sawzall to cut the bars up if it's only a one time thing?
sorry to hear that
 
I don't run any "bar" job nearly that fast.
Those are chucker speeds.

Decide if you want to run fast SFM, or be able to walk away from it for a bit.
Then program accordingly.

There is more to running "bars" than just a REPEAT button.


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Think Snow Eh!
Ox
 
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Just so's y'all can have a bloody cow:

I was running 1.75" tubing today on one lathe.
20' long bars.

6' sticking out the back of the support tube.

@ 1000 RPM it runs purty dog'gon true.
800 and below it will flop a bit.


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Git'r Done!
Ox
 
as Ox above.

16mm 303sticking out the liner about 300mm, I thinks that's 5/8" sticking out 12" for you backwards folk :stirthepot:. Running at 1600 rpm no problem, 1000 rpm flops a bit.
 
6' sticking out the back of the support tube.
Six feet ? Just making sure we didn't miss a ' here ...

I have done that a few times. Works okay ... until it goes bad. When it goes bad, it goes bad fast and big. It takes a little to make a 16x54 Pacemaker hop around like a bunny rabbit.

(I'm definitely not a safety freak and have proof of that, but the one-bladed propeller was an eye-opener. Lucky it wasn't a chest-opener. It could have been, actually, it happens that fast.)
 
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I've seen it happen before.
I have a barfeeder that has battle scars from one such incident.

I had the 4' loader slid back, and a stock tube in place for 12' bars.
Apparently the stock tube wasn't locked down in the stands, and had vibrated back, and once the end of the bar came out of it, WHAMMO! (and it wasn't a frisbie this time-o) You can see how it split the 1/8"+ steel framework of the feeder.

Doesn't hurt to have that reminder in your face daily.

DSCN3251.JPG



Also had an incident once that produced a cut in the insulation 10' up the wall near the LeBlonde. I don't recall the specifics there, other than it wasn't me running it, but that I had other employees in the building at the time as well. And that puts a chill down your spine for a bit.

In the case of the engine lathe, I think one of the root causes was likely that it was a smaller bar, running in a bigger bore, so it was already running out of center. Had it been bushed (like a production job on a CNC would likely be) then it prolly would have been OK.


Both of these incidences happened 25 yrs ago, +/-.


I have bars sticking way out quite often, but seldom are in the parameters of this type of issue. Like yesterday, before I set up that 1.75" tube, I had finished a partial run of some 1.75" 1018, that was sticking out, maybe 2'. I don't run that job, on that spindle - more than 1000 rpm. The 25K# machine will dance around the floor and fault out before that bar bends.

By far - IMO, the biggest danger in most stick-out situations is someone getting loose clothing caught up in it! I know of 3 incidences of people getting pony tails caught up in something, resulting as (1) impossibly lucky, (2) scalped, (3) scalped, broken neck, and dead. I seen the results of a PTO shaft catching my dads jeans up. Lucky to have walked (hobbled?) away from that, but life would catch up to him a cpl years later. My biggest concern here is to not get caught on a spinning bar end! I am generally working alone, so I know and understand the risks, and how to deal with them. Having employees around that is a horse of a 'nother color. Especially if they are inexperienced employees. I may git dead that way, it is possible, simply b/c over time, we all git lax about anything. I'm OK with that, just remember DNR!

Shop owner up town was running a drill press type job (just helping out on the floor - not a dummy by any means!) and had gloves on. About lost a hand. Came back out later with a sign stating not to wear gloves on this machine.


There are oodles of ways to git hurt or dead once you git'cher assets up off the couch and become a productive member of society. The key is to learn quickly what will git'cha, and how. Try to learn from other's mistakes! Keep your eyes open for concerns, and decide what to doo about them on the fly. Good judgment comes from bad experiences. Hopefully those early bad experiences were just good lessons, and not be life altering, or endings.


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I am Ox and I approve this post!
 
I can't disagree more than this Ox.
On the death I experienced with one employee was due to trying to save a little time. He needed 5 more parts that were 1/8" long. Rather than go saw off 6" to hold and make the parts, then toss the rem, he thought he could get by with it hanging out.
Sadly he didn't adjust any top RPM settings and paid for it with his life.

If you have a bar hanging out multiple feet, I hope you have some kind of loop around to prevent it from launching. It's scary as fuck to me and just not worth the $500-2500 part to F around and find out.

Be safe my man.
 
I can't disagree more than this Ox.
On the death I experienced with one employee was due to trying to save a little time. He needed 5 more parts that were 1/8" long. Rather than go saw off 6" to hold and make the parts, then toss the rem, he thought he could get by with it hanging out.
Sadly he didn't adjust any top RPM settings and paid for it with his life.

If you have a bar hanging out multiple feet, I hope you have some kind of loop around to prevent it from launching. It's scary as fuck to me and just not worth the $500-2500 part to F around and find out.
This above is a reminder that adequate training really does save lives. The affected zone of this incident and the one I posted are small but very important to avoid when the spindle is turning.
 








 
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