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Just a thought...CNC vs. Manual...

michael.kitko

Cast Iron
Joined
Oct 30, 2012
Location
Gales Ferry, CT USA
I ran across this video today on YouTube and must admit, I was a little shocked by the bias in it. I get that CNC is faster in a production setting and sometimes faster in a one-off part setting, given the complexity of the part, but this was not a very good example of the speed at which a manual machinist can move. Just for example, the whole part in this video could have been done in an X-Y table on a milling machine, just like the CNC machine. Definitely not trying to stir up a hornet's nest, but again, it was a very bad example of manual machining.

 

eKretz

Diamond; Mod Squad
Joined
Mar 27, 2005
Location
Northwest Indiana, USA
Sorry, that dude is about 2nd or 3rd year apprentice level in my book, if that. First on the setup: that should have been set up with a pilot on the aluminum baseplate that centered that part rather than dicking around aligning it visually. Also should have used an indexer rather than a rotary table - there is no reason to do the round work on the rotary instead of the lathe - where the part had obviously already been as it had been bored. Alternatively, could have milled both the pilot and the part on the indexer by just barring it around. He then blew the radius calculation and cut the radius at .993" instead of 1.00". Also I've never seen a boring head used with that much stickout on a small shank diameter like that. Shooting himself in the foot repeatedly.
 

doug8cat

Titanium
Joined
Jul 10, 2008
Location
Philadelphia
I get it ,I run a Lancer 2000 VMC 95% of time 70-80% of the time 2-40 production parts. The remainder I could do on a bridgeport style mill with DRO much faster and with much more ease. Guess it comes down to how many machines you are willing to have and type / size of parts you usally run.
 

michael.kitko

Cast Iron
Joined
Oct 30, 2012
Location
Gales Ferry, CT USA
Thanks for the comments back on this post, I was just hoping I wasn't the only one that thought that this was a terrible example of the differences.

I had to laugh at the escalator comment above, I liked that.
 

michiganbuck

Diamond
Joined
Jun 28, 2012
Location
Mt Clemens, Michigan 48035
Analogy of CNC to Manual:
CNC: you use an elevator to move between floors.
Manual: you use a staircase to move between floors.
Manual using digital readouts: you use an escalator next to the staircase to move between floors.
Good analogy rons:
The extraordinary initial cost and maintenance of an elevator or escalator would never be justified for a few people, or infrequent going from floor to floor
A staircase would not be adequate for many people or for frequent or delicate objects transport but may be justified for when the elevator is down.

Trying to justify one to the other is like saying what is best a race car, a bus, or a wheelbarrow for this task.
 
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gustafson

Diamond
Joined
Sep 4, 2002
Location
People's Republic
Right, turn the round part in the lathe
Bolt it to a fixture in a vise[which is a freshly drilled hole, no indicator needed
calculate the hole center locations for the reliefs[there are only 3 X+ and - being mirrored]
actually only 2 as Y is mirrored also
actually only one as the drawing is going to give you one on axis dimension
 

Thunderjet

Hot Rolled
Joined
Jun 24, 2019
If all you have is a computer geek with a drill index and a Chinese digital caliper, you need to buy a $100,000.00 machine to make your parts.

If you have a real machinist, or better yet a Journeyman T&D maker, you need a $2000.00 Bridgey and a few accoutrements.

Tough decision.
 

GregSY

Diamond
Joined
Jan 1, 2005
Location
Houston
The elevator analogy has some merit, but it's a pretty basic one at that. The CNC machine can be both amazingly slower than a manual machine, and also amazingly faster. Sometimes the elevator flies right up and saves your legs, but sometimes it stops at every freakin' floor and you have to wait 5 minutes for it to show up and someone farts in it.

The trick is to have both and use them as needed.
 

richard newman

Titanium
Joined
Jul 28, 2006
Location
rochester, ny
As we all know, any dope can post any shit on youtube and claim to be an authority. And the other dopes out there will believe it and cite him as a guru. For sure there is some great stuff out there, but most of it...
 

majohnson

Cast Iron
Joined
Jan 3, 2013
Location
Erie, CO
It was surprising to see how far down on the quill and the boring head shank he had thing set. He might be really good at cnc work, but his manual mill skills seem to be lacking.
 
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implmex

Titanium
Joined
Jun 23, 2002
Location
Vancouver BC Canada
Hi All:
I'm with the general consensus here; this guy is painful to watch.
He's not quite the worst I've ever seen but he's pretty close to the bottom of the barrel.
I'd be firing his ass if he was that bad as a 2nd year apprentice

If I spent that kind of time just clocking in my part, I'd already be dead of old age.

Not only that, he seems to have found a way to explain what he's doing in the most confusing way possible.

Not only that, as many of you have observed his setups are for shit in so many ways.

This is supposed to be an INSTRUCTOR at North Georgia Tech??
He's a fuckin' moron as a manual machinist.
I looked at the predecessor video where he mills the part on a CNC, his shit is better on that platform, but not very much better...still lots to criticize.

All those hoping to learn the trade from this institution, need to avoid this instructor...he's pretty much hopeless.

According to the intro blurb in the Youtube version, he teaches Tool and Diemaking at North Georgia Tech...I'd hate to see what those poor students of his are capable of when they're finished but I'm not impressed and I sure wouldn't hire North Georgia Tech grads based on the quality of the instruction coming from this guy.

Also he can't run a lathe to save his life...everything looks and sounds terrible and he seems to have no idea what he's doing wrong.
Maybe just a smidge of lube on the tip of his tool for starters...my Lovely Wife looked at me pretty weirdly when I yelled "Lube your fucking tool" at the computer... but I digress.

So as you may have guessed, IMO he didn't make his case convincingly.
I understand what he was trying to communicate, but he didn't do it very well.

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com
 

EPAIII

Diamond
Joined
Nov 23, 2003
Location
Beaumont, TX, USA
I am sure I am not the fastest or most accurate manual machinist, but that video was painful to watch. I gave up after about 3 or 4 minutes.

If he is an instructor, I would want my money back for that class.
 

gustafson

Diamond
Joined
Sep 4, 2002
Location
People's Republic
Elevator stairs
Manual machining: retrieving one sack of grain from the 5th floor via the stairs. If you have more than one sack, you are gonna get tired, because you can only carry one at a time, up and down the stairs, but for that one, whatever
CNC machining:The elevator really doesn't save a whole lot of time over the stairs for that one sack, but it is still easier. 50 sacks takes only a little longer than the one.
VMC: Electric fork truck drives the whole pallet onto the elevator.

Yes I will use CNC for one part. You make a mistake, big woop, throw another part in. This part would take 15 minutes to draw and you could then put nice tiny radius at every intersection and a chamfer on the top edge
 








 
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