# Cuttin'  it a little close like



## little ol' e (Oct 23, 2022)

Thought I had my calculations of the step jaw depth  correct. 
Nope...
Could have been a disaster lol.
Well, time to put a parallel in behind it, then shake off the goose bumps I got from it.
Making a sleeve bushing for a smaller diameter pin


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## YotaBota (Oct 23, 2022)

Yup, that is close to an "Oh Sh-t" moment, to be filed under "won't do that again".
What is your lathe and tool post?


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## little ol' e (Oct 23, 2022)

Its a 2 axis CNC Doosan lathe, Fanuc control Puma 2100B.  I don't run on a JIT schedule but, I wooed down the feed on this "Just in time"
 Wouldn't have got to the full 2" depth before turning for the second op with that set-up lol. 
I hear ya on the... Oh $h-t "won't do that again"
The aftershock would have been harder to shake off then the goose bumps had I hit the jaws again !


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## Janger (Oct 23, 2022)

Interesting lathe Eric. How old is it? How about some more pictures? I'm always glad to see CNC gear on the forum. Do you use Fusion 360 and the simulator? It's saved my butt a few times avoiding crashes.


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## little ol' e (Oct 23, 2022)

Hey Janger, 

Lathe is a 2014 . I've never tried Fusion 360 .  Cam Simulation certainly would have save my butt in many cases over the years without a doubt.
Using Solid works, Mastercam and Worknc. 
I Do backplot most of my cutter paths thou, just doesn't show any islands or cusp heights left behind after roughing with too big of a stepover.
For setups, I like to keep things close so to speak, not too much stick out on cutters or part sticking out too far from the vice jaws. 
The above picture was a bad quick measurement on the part stick out. Just trying to do a quick bushing can haunt ya sometimes when not paying close enough attention. The gut told me to double check as usual, when I didn't, the goose bumps made me turn the feed down quick to save the damages that could have happened.

I should start using the block simulation feature with clamps in place for 3D cam simulation on the mill thou. Have machined some step clamps, smoked a few cutters along the way. Especially trying to go through islands left behind from having my stepovers set to high after roughing blocks out, then sending the semi finisher in without noticing the island or road bump cusp height left behind.


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## little ol' e (Oct 23, 2022)

The hair on the back of my neck stood up after this 1. Felt a few more grey hairs poke through as well haha.

I asked the man in the machine "what the heck just happened" but he was speechless.

CNC certainly was a learning curve after manual machining in a tool and die shop for many years.


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## LenVW (Oct 23, 2022)

little ol' e said:


> The hair on the back of my neck stood up after this 1. Felt a few more grey hairs poke through as well haha.
> 
> I asked the man in the machine "what the heck just happened" but he was speechless.
> 
> CNC certainly was a learning curve after manual machining in a tool and die shop for many years.


Sorry about your shield damage - Eric.
I was a manual machinist at Ex-Cell-O - 40 years ago.
We specialized in custom boring heads and carbide insert cartridges.
There was a CNC department as well as carbide insert grinding stations.
After a few decades of machinery development & automation projects I am educating myself about the development of machining and operations that I can achieve on my little mini-mill.

If you are down to Kitchener sometime, there are a few CHMW members in the area.
Give me a call (M. 519-320-0384)


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## little ol' e (Oct 23, 2022)

Anyone like to shake out a guess on why I had to replace the window?


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## LenVW (Oct 23, 2022)

Maybe a flying tool or workpiece ?


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## little ol' e (Oct 23, 2022)

LenVW said:


> Sorry about your shield damage - Eric.
> I was a manual machinist at Ex-Cell-O - 40 years ago.
> We specialized in custom boring heads and carbide insert cartridges.
> There was a CNC department as well as carbide insert grinding stations.
> ...


That sounds good Len,

What cad/cam software did you choose?


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## Degen (Oct 24, 2022)

CNC lathe nice.

I've git a CNC using Centriod controls and their software.  For programibg I currently use their onboard Intercon system, it works but is definitely the most optimized tool path.  To do the optimization, I use the GwizardE as I can see the tool path line by line and adjust the Gcode from there.  NZviewer is a cloud based free version that does the same thing.  I believe both would work well for programming too.

As to shattering your glass, forgot to tighten the chuck? As the hit looks close to the chuck end and no mention of crash was made other than near miss.


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## little ol' e (Oct 26, 2022)

I was never a CNC lathe guy. So this is what I learned just recently . Well a few months back. Tried to figure out how the lathe launched the 8x12 piece of 4140 at me. 
Yes, I had to clean my drawers out after that 1 haha.
Too start, let's say...
The lathe jaws are all numbered ( well I think some cheap ones aren't) although I have some that are not. Why ? I dunno....


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## little ol' e (Oct 26, 2022)

This is what really happened lol.
The bottom of the lathe jaws  serrations are so close together I have a hard time seeing how many serrations I'm either inside or outside that need to be counted.
Yes, I should have used my mag base and indicated afterwards just to be sure it was running true haha.


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## DPittman (Oct 26, 2022)

little ol' e said:


> This is what really happened lol.
> The bottom of the lathe jaws  serrations are so close together I have a hard time seeing how many serrations I'm either inside or outside that need to be counted.
> Yes, I should have used my mag base and indicated afterwards just to be sure it was running true haha.


Wow those are fine serrations,  I can imagine that would be difficult to use. I wonder why so fine.


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## little ol' e (Oct 26, 2022)

You probably see where I'm going with this now lol..The chuck has numbers on it. 3 jaw- so 1-2-3 is engraved. Would have been good information to know before I riffled a few parts at myself...
Good thing I got that sorted out after a couple mishaps haha.
Because once I machine the jaws for specific diameters and depths, they need to go back in the same location, if not then, yup I need another new window haha.


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## little ol' e (Oct 26, 2022)

This was the window several months back. I took the other photo down so I'll through this 1 up instead.
Oh, the sound of the part hitting the window and bouncing inside the lathe till it was in the chip conveyor was like a 6 in the mag 1 in the pipe gun shots going off.  
But, it's all good now. Finally figured most things out...
So thats how you can take out your CNC lathe window.
That's all for now folks.


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## little ol' e (Oct 26, 2022)

Couple quick pictures of the lathe before I get busy here.
If you notice my live center no longer has a point to it either haha.
But its been replaced... several times lol.
Happy hump day everyone!
Play safe.


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## Dan Dubeau (Oct 26, 2022)

Nice lathe, shame about the crash.  CNC lathes still scare me a bit.  A lot can go wrong really quickly.  We have a nakamura tw-20 twin spindle at work.  So far I'm the only one here that knows how to run it, and it doesn't get used all that often, but is pretty handy, and a great money maker when it does.  I use the left spindle for collet work, and the right for chucking work.  Still have yet to figure out the live tooling, and spindle to spindle hand offs.  All programmed with finger cam.  

I haven't thrown a part yet, but then again I don't really "push" it, as we don't do production work.  It's tough to throw a part from a collet, but much easier with the chuck.  The chuck being on the right spindle, directly in front of the control at nut height is probably what's keeping me well within the limits .


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## little ol' e (Oct 26, 2022)

Since being a Tool maker for close to 35 years with no real lathe experience, other than turning bumpers and the odd broken punch or bushing in a pinch. My experience was pretty much nil...
The lathe certainly was a learning curve. I'd be lying if I said I wasn't scared myself when going through the learning process. 
Was using coolant for everything at the time with the lathe and was difficult to see my distance to go before nailing the jaws haha. 
I must say, the window is tough, the hub I was doing didn't come through it, spinning it at 3700rpm. Didn't take long to spit it out that's for sure. 
 Since, I was up close to that window watching my distance to go I figured I got lucky. I didn't have to shell out another 5k for new dentures.
luckily, I only had to change my underware and pluck a few more grey hairs out. Probably why I'm mostly grey now haha. 
 The 2 axis lathe suits me just fine these days. I'm still light years behind the live tooling, C&Y axis lathes. I load each part, no bar feed yet and I still encounter problems haha. 
I hope your enjoying the trade Dan, I've had many good years over the years. Enjoy it!


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## Dan Dubeau (Oct 26, 2022)

little ol' e said:


> Since being a Tool maker for close to 35 years with no real lathe experience, other than turning bumpers and the odd broken punch or bushing in a pinch. My experience was pretty much nil...
> The lathe certainly was a learning curve. I'd be lying if I said I wasn't scared myself when going through the learning process.
> Was using coolant for everything at the time with the lathe and was difficult to see my distance to go before nailing the jaws haha.
> I must say, the window is tough, the hub I was doing didn't come through it, spinning it at 3700rpm. Didn't take long to spit it out that's for sure.
> ...


Windows in CNC lathes, are a lot tougher than the 1/8" acrylic windows in most CNC mills.  Ours looks pretty beefy, I hope I never have to test it.

I've had an interesting career path and while I'd like to say it's been fun the whole time (mostly automotive industry.....checking fixtures ).  almost 19 years in now, but it has been good to me though.  Never a dull moment.  Should be able to ride the wave until retirement.  Hopefully.

Our Nak is only a c axis with live toys.  I've had to learn it all by myself from books, manuals, and the internet, but have just never found the time or need to get into that side of it, so it just gets used as a simple 2 axis.  Would love to have it at home, and could probably keep it fed with work, but I don't have the juice for it, nor the space.  It sits a lot at work because I don't have time to find work for it, nor do I want to be the one to babysit it all the time.  A smaller lathe like a tormach, or Omniturn will eventually find a spot in my home shop though or I'd love to retrofit a hardinge TL or similar someday.  To many projects, too little time.


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## Degen (Oct 27, 2022)

I must say the biggest thing in understanding CNC is translating programmed actions to movements on a machine (be it lathe or mill).

A good simulator is what is need to see the program and actions at the same time virtually (and though undesired crash virtually if needed).

Obviously Fusion, Solidworks, Mastercam as the big names.  GWizardE as a small (what I have) and less costly system and Nxviewer as a cloud based free version. 

By no means am I a G-code wizard, I find it an extremely poorly documented and no consistent language across platforms and machines (and this comes from one that started programming in a lot of the old languages in the early 80's including hexcode).  I do let intermediate platforms do the grunt work (like those mentioned above and in my case Intercon from Centriod) and use a similuator to tweak the resulted G-code to optimize. 

The second biggest secret is starting from a 0,0,0 point that and marking that on your drawings, this reference and its location to "do not hit points" determines your work holding and as all your tools reference that point.  Since I figured that out I have zero crashes.

Third secret is optimized tool path,  this is something that we can also apply in manual machining.  The best paths provided the shortest cut time while providing the longest tool life resulting in the best finish. There is a fine balance between the three.  Again good simulators are important here (and sometimes a few scraped parts for trial runs).

In my case I am running significantly faster feed rates than I ever did or could manually and achieving better results more consistently.  Example fasted movement with power feed was 6 IPM flat out though cuts ran at about 2-2.5 IPM with a 0.025 depth and full 1/2 endmill cut, now I'm running 20 IPM, with a 0.050 depth same endmill, though longer and more consistant tool path which results in a more than 1/2 of the time required to complete a part consistant repeatable dimensions.


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