Instructor approves cutting steel at 2000sfm

[CarbideBob]

An even bigger reason for firing him is that he creates a dangerous situation in the school shop.

Is it all that dangerous?
What happens here even if a 50 HP and 60,000 pound machine?
Bob

 

[mhajicek]

Is it all that dangerous?
What happens here even if a 50 HP and 60,000 pound machine?
Bob

Well, since it's a 30 taper, which have notoriously weak pullstuds, as people have said the holder can take off like a bullet and punch through the enclosure. Not terribly likely, but I wouldn't say impossible.

 

[Larry Dickman]

An even bigger reason for firing him is that he creates a dangerous situation in the school shop.

what's even worse is they unleash a sea of ill trained operators who will go to their graves thinking they're doing it right, because that's how they were taught

 

[Fancuku]

I don't think your instructor knows the difference between 2000 SFPM and 2000 RPM'S

lol
I was thinking the same thing.

 

[Milland]

I will be forever brokenhearted if I don't find out what the end result was...

 

[sendithard]

@ShopRatCNC

I love how you teach them at the lower end of the risk curve....You may have a bad taste of Titans. I have gone thru their entire course....they do NOT teach aggressive recipes in their educational series. We all know they push the boundaries on other videos....but I think they have been quite reasonable in their academedy.

 

[sendithard]

Bro, I ain't going nowhere You may also be heartbroken when I step in and prevent such a disaster.

 

[sendithard]

I'm not trolling...I'll fill you all in when it happens, if it happens....I'm still protesting until we get the gcode to the controller. I'm trying to avoid issues so I appeciate everyones talk.

 

[Cole2534]

I'm not trolling...I'll fill you all in when it happens, if it happens....I'm still protesting until we get the gcode to the controller. I'm trying to avoid issues so I appeciate everyones talk.

Post up some code, let's see this baby rock n roll!

Programmed via Mazatrol

 

[Scruffy887]

Sigh. Click bait. You are a student in a night school? But for sure a student. I for sure would run it. EXPERIENCE! Do you think an 18" carbide saw blade can cut cleanly through a 1" x 1.5" steel bar? At 4000 RPMs? 100 meters/min feed? Hell yeah it can. Cut through 2 of them like nothing. There were 3 in a row and there were no teeth left for the third bar. Bad EPROM and air freight from Germany and installation was back on schedule. Sure as hell woke us up.

 

[sendithard]

Sigh. Click bait. You are a student in a night school? But for sure a student. I for sure would run it. EXPERIENCE! Do you think an 18" carbide saw blade can cut cleanly through a 1" x 1.5" steel bar? At 4000 RPMs? 100 meters/min feed? Hell yeah it can. Cut through 2 of them like nothing. There were 3 in a row and there were no teeth left for the third bar. Bad EPROM and air freight from Germany and installation was back on schedule. Sure as hell woke us up.

I literally recently signed up for the site you goof ball. Do you have any brain cells? I'm simply the guy that pays attention to fundamentals that you don't like.

 

[Volitan]

Today, the instructor tells him I am wrong and to run the 3/4" HSS endmill at max rpm(10,000), b/c we are only cutting at .4 doc.

Please try to get a cell phone video when he runs this.

 

[Radar987]

I've learned a ton from my machining tech instructor

No you haven't.

 

[Scruffy887]

I literally recently signed up for the site you goof ball. Do you have any brain cells? I'm simply the guy that pays attention to fundamentals that you don't like.

Some advice. Don't call people names, makes you come across as an asshole. Do NOT assume the brain cell count of anybody you have never met in person. I doubt you are qualified to hand me a caliper by what you post, but you may be a fookin brain surgeon (well junior brain surgeon). And I like fundamentals, and for damn sure like to push them in most aspects of my life. Comfort zones need to be tested and expanded. Run the program, push till something breaks. Back off just enough to git er done.

 

[plastikdreams]

Just for a little action, I ran a 5 flute .500 40° helix .030 carbide AlTiN coated, .100 deep full width 1800 rpm 10 ipm (coulda gone faster) on a Bridgeport, air blast in o1 steel. (the carnage) all was good until I took a chip to the corner of my left eye...all is well and was able to finish the task...hurt like a mother fucker for about a half hour lol.

Beat that!

 

[G00 Proto]

Just for a little action, I ran a 5 flute .500 40° helix .030 carbide AlTiN coated, .100 deep full width 1800 rpm 10 ipm (coulda gone faster) on a Bridgeport, air blast in o1 steel. (the carnage) all was good until I took a chip to the corner of my left eye...all is well and was able to finish the task...hurt like a mother fucker for about a half hour lol.

Beat that!

I was doing a similar experiment using 1.5” long 1/8” 3 degree drafted endmill around the outside of a standing mold core. The cut sounded funny so I walked around the back of the open mill table just as the cutter broke. It flew up several feet and buried itself through my lower lip all the way to my incisor. It bled and hurt a lot.


Sent from my iPhone using Tapatalk

 

[plastikdreams]

I was doing a similar experiment using 1.5” long 1/8” 3 degree drafted endmill around the outside of a standing mold core. The cut sounded funny so I walked around the back of the open mill table just as the cutter broke. It flew up several feet and buried itself through my lower lip all the way to my incisor. It bled and hurt a lot.


Sent from my iPhone using Tapatalk

Got me beat!

I had a punch explode trying to get a stuck pin out, took a few days to dig all the shrapnel out of my fingers lol.

I used to wear a face shield, I've been meaning to go back to it.

 

[Strostkovy]

Got me beat!

I had a punch explode trying to get a stuck pin out, took a few days to dig all the shrapnel out of my fingers lol.

Long ago my dad was in a shop class and they demonstrated heat treating by tempering punches all differently and showing the failure mode of each, including brittle failure. In that same class my dad tempered a wrench as hard as he could and proceeded to slice his hand when it snapped.

 

[guythatbrews]

OT old crash this thread just recalled to mind

Sort of off topic here. This thread reminded my of a crash I saw long ago, like a new Mori sl-2 ago.

Guy from England was visiting the owner's son, who was sort of a dummy. In the shop we were all kids and the visitor was a pretty nerdy english home shop hobbyist sort so we were getting a kick out of watching him. He'd never seen a cnc lathe run so the boss told Brent, the guy setting the thing up, to press the green button and show the little guy what it woud do. Brent said it wasn't set up yet. The son said awww go ahead and show him what it will do. This went back and forth several several times until boss's son finally told Brent to "just push the goddamn button". Brent closed the door and pushed the GD button. The cycle started and the indexable drill came down and crashed right into the chuck. The little british guy musta did a personal best vertical jump. Brent turned to the Brit and in a deapan said "what did you think of that?" Boss's son just stood there like a dummy. We all howled. Like I said we were all kids and we were so proud of Brent.

Luckily no blood on the floor but ruined tooling and misaligned machine. And a shamed boss's son.

Now for the on-topic rest of the story. Guy in power was a dummy and put the operator/programmer in a bad spot, just like this idiot instructor. Hopefully nobody will get hurt. Or better yet he will see reason.

It has been my long experience running HSS endmills in mild steel w/o flood coolant just mist or brushed on that much over 100 SFM and tool life goes to hell in a hurry. That has only been on manual stuff. Never have used or very, very sedlom used HSS in the CNC's. Out of curiosity I googled HSS endmill speeds and feeds. For 1/2" 2 flute em slotting 300 BHN alloy steel .25 deep regal cutting tools suggests 360 SFM and 11 IPM. Chip load sound reasonable to low but that SFM is crazy high and 300 BHN is not mild steel territory either. That is carbide speed. Maybe the instructor got his info from some chart like this, or maybe a forum somewhere. Lots of bad info out there! Or maybe he has SFM and RPM mixed up. I don't have a machining center anymore but if I did I'd try the regal recommendation. It's not inherently dangerous and now I'm really curious if it would work for any amount of time at all.

 

[plastikdreams]

Sort of off topic here. This thread reminded my of a crash I saw long ago, like a new Mori sl-2 ago.

Guy from England was visiting the owner's son, who was sort of a dummy. In the shop we were all kids and the visitor was a pretty nerdy english home shop hobbyist sort so we were getting a kick out of watching him. He'd never seen a cnc lathe run so the boss told Brent, the guy setting the thing up, to press the green button and show the little guy what it woud do. Brent said it wasn't set up yet. The son said awww go ahead and show him what it will do. This went back and forth several several times until boss's son finally told Brent to "just push the goddamn button". Brent closed the door and pushed the GD button. The cycle started and the indexable drill came down and crashed right into the chuck. The little british guy musta did a personal best vertical jump. Brent turned to the Brit and in a deapan said "what did you think of that?" Boss's son just stood there like a dummy. We all howled. Like I said we were all kids and we were so proud of Brent.

Luckily no blood on the floor but ruined tooling and misaligned machine. And a shamed boss's son.

Now for the on-topic rest of the story. Guy in power was a dummy and put the operator/programmer in a bad spot, just like this idiot instructor. Hopefully nobody will get hurt. Or better yet he will see reason.

It has been my long experience running HSS endmills in mild steel w/o flood coolant just mist or brushed on that much over 100 SFM and tool life goes to hell in a hurry. That has only been on manual stuff. Never have used or very, very sedlom used HSS in the CNC's. Out of curiosity I googled HSS endmill speeds and feeds. For 1/2" 2 flute em slotting 300 BHN alloy steel .25 deep regal cutting tools suggests 360 SFM and 11 IPM. Chip load sound reasonable to low but that SFM is crazy high and 300 BHN is not mild steel territory either. That is carbide speed. Maybe the instructor got his info from some chart like this, or maybe a forum somewhere. Lots of bad info out there! Or maybe he has SFM and RPM mixed up. I don't have a machining center anymore but if I did I'd try the regal recommendation. It's not inherently dangerous and now I'm really curious if it would work for any amount of time at all.

Personally I don't run hss ever anymore unless I absolutely have to, eg using a .4375 hss endmill for a counterbore in 954 bronze. I've gone so far as to buy my own tooling just to make sure I have what I want. The Kennedy has a drawer full of endmills from .375 - 1.000 endmills