WHO NEEDS CNC?

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SteveM
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Re: WHO NEEDS CNC?

Post by SteveM » Fri Sep 21, 2018 10:48 am

One of the things I think some miss in Dave's videos with his turret lathe is that the bulk of the time is not being used by things like switching tools and moving the stock in. All of that happens pretty quickly.

Most of the time is the actual machining.

The time to tap, chamfer, part, etc... are about the same time a CNC machine of similar size and capability would take.

For what Dave is doing on that machine, running that with CNC isn't going to go all that much faster because the machining time is going to be the similar.

Steve

Geezer
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Re: WHO NEEDS CNC?

Post by Geezer » Fri Sep 21, 2018 3:16 pm

Is there anything from the steam era that
would need a CNC ?

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Re: WHO NEEDS CNC?

Post by Harold_V » Fri Sep 21, 2018 3:36 pm

It isn't a matter of "need". CNC allows for repetitive cuts without human intervention, and yields parts that are far more consistent than those produced by the average guy on the machine, many of whom use tolerance as an excuse for poor skill levels. That isn't true of all machinists, of course. Some (a small percentage) have extraordinary skills, along with considerable personal pride in doing the best they can, and can often produce parts to exacting standards, which a CNC does routinely.

I'm not proposing that CNC is a requirement---simply stating that a CNC, once operational, will run and produce parts, doing so better than the average human will. It doesn't take breaks, and it (generally) doesn't make mistakes. Parts come off a CNC without "shop wear", which isn't always true of manually produced parts. All depends on the people doing the work, and the setups chosen.

What CNC has done for the machining trade is to permit making more difficult parts without a scrap rate that was common when humans made decisions. They have improved the quality of work performed immeasurably, lowering the cost of parts in the process. So much so that some machines (like jig borers) have been slowly eliminated from shops, as a CNC has the ability to perform their tasks. All depends on the CNC, of course.

I've made mention on countless occasions that I was proud to have worked my entire productive years without the use of CNC's, and not so much as a DRO to aid in the work I did. That doesn't mean that I don't understand the benefits of CNC use. Sure the work can be done without one. It can be done faster and better with one, however. They don't take breaks, they don't BS with their fellow CNC's, and they have the ability to work while you sleep.

Smoke 'em if you got 'em, but don't feel obligated to smoke. You can live perfectly well with or without a CNC. The choice is yours. There is no right or wrong position in the matter.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

Geezer
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Re: WHO NEEDS CNC?

Post by Geezer » Fri Sep 21, 2018 5:33 pm

Very well said young man.
But, I don’t think there were any items engineered/drawings produced
that would require more than manual machining in that era.

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JTolan
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Re: WHO NEEDS CNC?

Post by JTolan » Fri Sep 21, 2018 10:35 pm

As a machinist with countless hours on both types of machines, manual and cnc. As with anything, if you are willing to learn you can get the most of of your tools. You will never be able to do what you can do on a cnc with a manual machine. It's impossible. While you can argue in the live steam hobby we will never have five or six axis parts, because locomotives were built without those tools.

The idea that cnc machines are only good for production is wrong and outdated. I can set up and run a 2d profile in stainless steel on the cnc router, plasma, laser or waterbed faster than I can get set up on the manual.
You can turn a bell profile on the lathe faster than you can think about making a pattern. Running one off parts with conversational coding is easier than turning the handles. Using a proper program to do the cam takes less time than to find the piece of stock.
As for talent. Knowing feeds, speeds, work holding etc is just as, if not more important with cnc, it just makes life easier to not turn the handles yourself.
Making complex profiles on a machine like a bridgeport is impossible, but when you tell the robot to do it, its fantastic.
However, with the advanced technology, 3d printing, cnc machining, computer aided design. We can build and create parts in ways and at speeds never thought possible.

I run them both, enjoy them both, have hundreds of hours on both. Its another tool to get the job done. No reason to be limited because it once you start its hard to go back.

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JTolan
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Re: WHO NEEDS CNC?

Post by JTolan » Fri Sep 21, 2018 10:43 pm

So to answer the question, "who needs cnc?"

The answer is anyone who wants to make parts, accurately and repeatdly. While manuals will always have their place, cnc machines expand the horizons of what is possible to a machinist.

I enjoy running my 20s era tools but those belong as a hobby.

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Trainman4602
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Re: WHO NEEDS CNC?

Post by Trainman4602 » Fri Sep 21, 2018 11:00 pm

I can make parts Accurately and repeatedly on my manual Hardinge lathe to the .0005 tolerance. I made 60 bonnets for my check valves all perfect. I don't agree with you that only CNC lathes can make accurate parts. How did we do it before CNC was invented.
ALLWAYS OPERATING MY TRAIN IN A SAFE MANNER USING AUTOMATIC AIR BRAKES

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JTolan
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Re: WHO NEEDS CNC?

Post by JTolan » Fri Sep 21, 2018 11:04 pm

I never used the only qualifier. I'm sure you can make parts accurately on your lathe. I meant that with cnc machines you can make parts accurately and repeatedly in a manner not possible manually.
Last edited by JTolan on Fri Sep 21, 2018 11:31 pm, edited 1 time in total.

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JTolan
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Re: WHO NEEDS CNC?

Post by JTolan » Fri Sep 21, 2018 11:20 pm

We survived without cnc in the same way our culture survived with horse drawn carriages before the automobile. Without a doubt the horse got to your destination correctly, but today a vast wouldnt choose the horse, for many similar reasons as to why I would use a dro before a travel dial. Or the cnc lathe before my manual.

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Trainman4602
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Re: WHO NEEDS CNC?

Post by Trainman4602 » Sat Sep 22, 2018 12:37 am

JTolan wrote:
Fri Sep 21, 2018 11:04 pm
I never used the only qualifier. I'm sure you can make parts accurately on your lathe. I meant that with cnc machines you can make parts accurately and repeatedly in a manner not possible manually.
What accuracy are you talking about .000005? Truthfully .001 +- is good enough form any live steam work THIS IS NOT ROCKET SCIENCE.
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Atkinson_Railroad
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Re: WHO NEEDS CNC?

Post by Atkinson_Railroad » Sat Sep 22, 2018 5:54 am

An analogy of using pen and paper, the typewriter, and later on... the word processor
utilizing the power of a computer comes to mind with all of this discussion.

One could argue that Dave is not using film cameras and editing his video content with a razor blade.

Someone might say, they could draw a line in "earth" 2 feet in length and use their own two feet
for measuring it... faster than it could ever be produced using any kind of machine.

Conversations outside [this box] are talking about how we're into a Fourth Industrial Revolution.

A striking aspect to all of these new arrangements of technology for me... is how anyone of us can now Invent, Design, Prototype, Manufacture, and Sell our gizmos directly to the customer using a little ole forum such as this one here at Chaski.

It's really pretty incredible.

If I do need to cut a string. I'll reach for a pair of sizzors instead of using my teeth.

John

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Re: WHO NEEDS CNC?

Post by Geezer » Tue Sep 25, 2018 12:13 pm


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