Machining confession thread.

[rjwalker1973]

Ha ! Busted !

Someone once gave me a box of kyocera 'cermets' ? that were incredible. Sharp on the edges, not like ceramics, but cut like ceramics, sparks flying everywhere, hard steel, stainless, never tried aluminum but anything tough ? dry ? hard ? them things were absolutely killer. And the finish ? shiny shiny, shiny boots of leather.

And after the box was gone, I could never find them again. Any idea what they were ?


And someone has to make the machines that make the teeth on the gears ten feet in diameter

View attachment 407399

(I'd come up with another screwup story just to keep on-topic but unfortunately that's the only thing I ever screwed up ... unh-hunh)

I literally worked across the parking lot from the cutting tools division and it took me week to get inserts. We used the pvd coated and they was awsome.

 

[projectnut]

In the last 40+ years I've seen very few competent machinists make mistakes. But then I was told by an old German toolmaker "If it can be fixed before the boss sees it, it never happened!"

As for the statement: "(I'd come up with another screwup story just to keep on-topic but unfortunately that's the only thing I ever screwed up ... unh-hunh)",

I can only respond that there are very few people in the world as close to perfect as you and I, and now I'm beginning to wonder about you.

 

[Freedommachine]

I cannot grind a drill by hand. I can kiss each flute on a wheel once or twice to freshen up the edge, but any more than that and she's done; you're gonna need to grab a new one.

Also, I have no idea how a lathe taper attachment functions.

 

[CarbideBob]

I cannot grind a drill by hand. I can kiss each flute on a wheel once or twice to freshen up the edge, but any more than that and she's done; you're gonna need to grab a new one.

Welcome the club. Never been even halfway decent at this. I can not hand point a drill worth a shit.
I know all the entry, roll, twist, edge balance, fishtail check but still end up with not a great drill tip. As you said 4 to 10 good holes.
Weird thing. My machines make drills in 10 different types of points in thousand plus runs to crazy tolerances.

 

[Tyrone Shoelaces]

I can hand grind a drill point alright.
When I was a kid of about 18 we were just 10 minutes from packing up on Friday afternoon when the foreman ( who really didn’t like me ) came over with a brass name plate for his garden gate. “ Drill and countersink this for me in the four corners and then put it on my desk “ he growled.
So I drilled the four 3/16” holes and then hand ground an ordinary 3/8” drill to a 90 degree angle for the countersink.

The first three holes went great, nice smooth countersink. But disaster struck on the last hole. The drill grabbed and went straight through. F*#k . Nothing I could do but put the name plate on his desk and go home.

All weekend I was dreading Monday morning coming ! When I got in the shop to my amazement he never mentioned it. He just made my life a misery instead.

Moral of the story - when countersinking brass - TAKE THE EDGE OFF THE DRILL FIRST !

Regards Tyrone

 

[metal-ica]

Many years ago, I banged a chick on the workbench next to my lathe.

Forgive me father for I have sinned....but I'd do it again.

 

[DouglasJRizzo]

I cannot grind a drill by hand. I can kiss each flute on a wheel once or twice to freshen up the edge, but any more than that and she's done; you're gonna need to grab a new one.

Also, I have no idea how a lathe taper attachment functions.

Same here. Dad had a Black Diamond Drill grinder, and so do I. He also had an Oliver helical point drill grinder for larger drills. I never learned to freehand a drill on the grinder. Or sharpen a knife/saw. I would see dad do it on the Baldor, but I never learned that.

Never used a lathe taper attachment either. In fact, I've hardly EVER used a conventional lathe and used a mill only a little bit more. I was CNC from almost day 1. That's why I'll set up the CNC lathe or machining center for one part, even though the lathe or mill may be open.

 

[CarbideBob]

I am a master machinist and grinder.
Started in 1968.
Never a mistake or oops expect when not well guided into the process.
I have to blame all the others above .. not my fault.
Take some laugh time here.
I have done so much wrong and fucked up many, many thousand of dollars.
So am boss and the employee does such. He is "all shit will I get fired" .
Me "Not a fucking chance in hell. I just invested a lot of money into training you."

We all do puck up stuff. Try to understand when your employees do the same.

 

[Gearclash]

We all do puck up stuff. Try to understand when your employees do the same.

Yessir.
Minor fluff up occurred last night. Guy responsible asked what he owed me for straightening it out. I said, "if you can prove I’ve never made a mistake, you can pay me."

Recently somehow forgot, on the last and finish pass of an ID cut being made on a mill by using a boring bar mounted to the mill table, that mills don’t show X travel in diametral change . . . its linear you idiot, just like it was for all the previous cuts that you remembered that little fact for . . . thankfully it didn’t scrap the part -- just no extra meat to hone out.

 

[Freedommachine]

That's why I'll set up the CNC lathe or machining center for one part, even though the lathe or mill may be open.

Early on, I spent 2 years as the low man in a farm type job shop with a total of 3 employees. I got to run a lot of cool manual stuff but it was kept simple for me. Things like stacking gear blanks on the hobb; running the shaper, horizontal mills, roughing out parts on the W&S turret lathes, cutting stock and my least favorite; hours standing in front of a do-all band saw cutting out whatever shape the boss needed from the thickest material he could find. I didn't care much for that job back then but I learned a lot about how things were done before computers.

This was around 2009 and there wasn't a computer in the shop unless you include the 1 Bridgeport with an Anilam crusader 2 control .

Since then, I've done a bit of everything - except oddly enough, common cnc turret lathes. I spent a year running a VBM with a 10' diameter table but I've never typed a line of code or touched off a tool on a traditional cnc turret lathe in my life. Milling is my strong suit.

I'm on weekend shift at the day job now so I've thinking about approaching one of my vendors to see if they will train me on their quick-turns in exchange for some free labor.

 

[EmGo]

I learned a lot about how things were done before computers.

More important, you learned about cutting metal. It seems like a lot of people who started with "cnc" never learn the basics.

 

[PDW]

Recently somehow forgot, on the last and finish pass of an OD cut being made on a mill by using a boring bar mounted to the mill table, that mills don’t show X travel in diametral change . . . its linear you idiot, just like it was for all the previous cuts that you remembered that little fact for . . . thankfully it didn’t scrap the part -- just no extra meat to hone out.

I put a label next to the adjusting handwheel on the Kearns S type HBM.

"This wheel measures changes in RADIUS not DIAMETER".

No guesses why it's there...

PDW

 

[animal12]

When ya cut something 3 times & it's still too short . Experience is something you don't have till the day after ya need it .
animal

 

[???]

More important, you learned about cutting metal. It seems like a lot of people who started with "cnc" never learn the basics.

I have always said that without the basics the CNC just enables you to cock it up even quicker than before.

 

[???]

I cannot grind a drill by hand. I can kiss each flute on a wheel once or twice to freshen up the edge, but any more than that and she's done; you're gonna need to grab a new one.

Also, I have no idea how a lathe taper attachment functions.

I thought all lathes came with built in taper, or at least those I get to work on.

 

[Freedommachine]

More important, you learned about cutting metal. It seems like a lot of people who started with "cnc" never learn the basics.

I did learn a lot about cutting metal but I don't think that necessarily gives me a big advantage over those who didn't run manual's.

Someone who can job shop with a cnc lathe will smoke my time on the same job any day.

I think in this industry, we all have some particular thing that we specialize in based on the work we do. Milling, turning, grinding, swiss, screw machines, EDM, welding, ect.
Those who choose to only learn enough to get by will never really improve. Those of us who refuse to stop learning will only become more versatile - which is why I need some hands on training for cnc lathes with live tooling. My little one man shop could really benefit from cnc turning capability.

 

[Freedommachine]

I thought all lathes came with built in taper, or at least those I get to work on.

Haha, I know right? I love turning long shafts where you have to give the cross slide a 0.0005" bump every 6" or so to stay in tolerance . Since you're on the other side of the world, I wonder if your lathes taper the opposite direction?

 

[EmGo]

I love turning long shafts where you have to give the cross slide a 0.0005" bump every 6" or so

Emery cloth is your friend

I did learn a lot about cutting metal but I don't think that necessarily gives me a big advantage over those who didn't run manual's.

Look around even here .... "Why am I getting this terrible finish ?"

Umm, it's chatter, you are using a 1/4" four-flute end mill in aluminum and it's sticking out 9", the part is held down by a single 5/16" bolt screwed into a piece of 1/8" masonite, and you are turning the cutter backwards.

Otherwise, looks perfect ....

"But it worked fine onscreen !"

Exactly.

 

[Tyrone Shoelaces]

A really experienced pal of mine was trying to drill a job on a pillar drill one day. He’d drilled a million holes on that drill previously. He remarked to me “ This bit‘s struggling today “. I said “ That’s because you’re running in reverse ! “
All of us have brain fade from time to time, especially first thing in the morning.

Regards Tyrone

 

[???]

One of the training instructors at Toyota told me this. The apprentice said he couldn't get a decent finish on his thread. The instructor who didn't like to leave his air conditioned office asked all the normal questions, centre height, tool ground correctly etc. There was a lot of back and forth with the apprentice bringing the lathe tool to him etc. He eventually went out to check, the apprentice had the feed lever engaged incorrectly and was running in reverse so he could cut a RH thread.