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Model Forum / General / Models / November 2007



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Serious CNC lathe...

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Tony Jeffree - 26 Nov 2007 20:56 GMT
Interesting video here:

http://www.youtube.com/watch?v=oGq-9NNmr3o

Shame about the commentary/music, but the polygonal turning is pretty
cool.

Regards,
Tony
Steve - 26 Nov 2007 21:48 GMT
> Interesting video here:
>
[quoted text clipped - 5 lines]
> Regards,
> Tony

Makes the spindle control on my lathe a bit pre-historic :-((
Myford Matt - 26 Nov 2007 22:03 GMT
Amazing stuf

--
Myford Mat
David Littlewood - 27 Nov 2007 01:00 GMT
>Interesting video here:
>
[quoted text clipped - 5 lines]
>Regards,
>Tony

Indeed. Guess I will have to wait until my local second-hand dealer has
them at a couple of thou though!

Would be interested to know what language the commentator thought he was
speaking.

David
Signature

David Littlewood

Trevor Jones - 27 Nov 2007 13:53 GMT
>> Interesting video here:
>>
[quoted text clipped - 13 lines]
>
> David

 I noticed that too! I suppose he was a starving actor reading the
script provided, as stranslated to english, by the engineer back in the
"home" country.

 Kinda interesting, but understandable for the most part.

 Cheers
  Trevor Jones
steamer - 27 Nov 2007 17:19 GMT
>  Kinda interesting, but understandable for the most part.
    --Well that makes one of us! How the heck does that thing work? I'd
love to see a slow-motion video of that process...

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       Hacking the Trailing Edge!  :  to Tom Nelson?
                         www.nmpproducts.com
                  ---Decks a-wash in a sea of words---

rsss - 27 Nov 2007 18:18 GMT
steamer Wrote:
> >  Kinda interesting, but understandable for the most part.
> --Well that makes one of us! How the heck does that thing work? I'd
> love to see a slow-motion video of that process...
>
> -

seems fairly simple. It's just a giant flycutter, with the rotation
synchronised so that the work moves the necessary number of degrees i
the period when the cutting bit isn't there.

if you rotate the cutter twice as fast as the work, the first strik
would be on one side of the work and the second on the face 180 degree
from the first.  Or rotate work and tool at the same speed and have th
same number of arms as you want flats, a tool with six arms woul
produce six flats.

It's exactly the same principle as walking a pair of compasses roun
the circumference of a circle.

You should be able to demonstrate the effect simply by mounting
cutter in a powered toolholder on the crosslide and the work in th
headstock with a calculated, controlled RPM.

But I still have trouble visualizing the actions of a wobble broach

--
rss
DR_G - 27 Nov 2007 22:43 GMT
steamer Wrote:
> >  Kinda interesting, but understandable for the most part.
> --Well that makes one of us! How the heck does that thing work? I'd
[quoted text clipped - 5 lines]
> www.nmpproducts.com
> ---Decks a-wash in a sea of words---

Try this for size:

http://video.google.com/videoplay?docid=-7831550688320827327

Cheers,

Garth

--
DR_
steamer - 28 Nov 2007 20:51 GMT
>Try this for size:
>http://video.google.com/videoplay?docid=-7831550688320827327
    --Thanks! Makes more sense than my easily-fooled intuition! :-) I
had convinced myself that sort of motion would produce crescent-shaped cuts..

Signature

       "Steamboat Ed" Haas         :  Whatever happened            
       Hacking the Trailing Edge!  :  to Tom Nelson?
                         www.nmpproducts.com
                  ---Decks a-wash in a sea of words---

Peter Fairbrother - 28 Nov 2007 23:32 GMT
>> Try this for size:
>> http://video.google.com/videoplay?docid=-7831550688320827327
>     --Thanks! Makes more sense than my easily-fooled intuition! :-) I
> had convinced myself that sort of motion would produce crescent-shaped cuts..

A bit off-topic, but one of the tests when I was learning was to make a
1" cube from a 1.25" length of off-square-cut 1.5" round bar - on a
lathe. All sides, and squarenesses, had to be within one thou, and
within a few tenths was better.

You could make a 0.900" cube if you messed up, or an 0.800" cube, and so
on ...

-- Peter Fairbrother
Austin Shackles - 29 Nov 2007 13:05 GMT
>>> Try this for size:
>>> http://video.google.com/videoplay?docid=-7831550688320827327
[quoted text clipped - 8 lines]
>You could make a 0.900" cube if you messed up, or an 0.800" cube, and so
>on ...

I bet yer could.  Chances are you need a 4-jaw chuck, an' all :-)
Signature

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Travel The Galaxy!  Meet Fascinating Life Forms...
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Trevor Jones - 29 Nov 2007 00:44 GMT
>> Kinda interesting, but understandable for the most part.
>
>     --Well that makes one of us! How the heck does that thing work? I'd
> love to see a slow-motion video of that process...

 The polygon turning? Search YouTube. I am almost certain that there is
a company video on there with a slow-mo animation showing the process.

 It is simply the coordination of the lathe spindle speed, and the
cutter tip passing by. (Simply. There's a misuse of the word!)

 Cheers
  Trevor Jones
M_T - 29 Nov 2007 13:38 GMT
A few years ago there were similar vertical milling attachments to do things
like hexagons on bolt heads.

A tipped cutter with a splined shaft through it went down to a gearbox on
the table via a universal joint. This drove an offset collet head which held
the workpiece.

All obsolete now though. These type of things eat up carbide inserts though
due to the intermittent cutting action.

M_T

Professional Engineer.

"steamer" <steamer@sonic.net> wrote in message
news:<474dd4ba$0$36399$742ec2ed@news.sonic.net>...

> DR_G <DR_G.30qdgn@rcgroups.com> wrote:

> >Try this for size:

> >http://video.google.com/videoplay?docid=-7831550688320827327

>     --Thanks! Makes more sense than my easily-fooled intuition! :-) I

> had convinced myself that sort of motion would produce crescent-shaped
> cuts..

>         "Steamboat Ed" Haas         :  Whatever happened

>         Hacking the Trailing Edge!  :  to Tom Nelson?

>                           www.nmpproducts.com

>                    ---Decks a-wash in a sea of words---
Alan Marshall - 27 Nov 2007 16:50 GMT
What sort of rpm and feed rate do you think that was cutting at. Was it a
steel component ... looked as if it might be?
campingstoveman - 27 Nov 2007 17:09 GMT
Gentlemen,

As a service engineer on machine tools in the 80's I worked for a company in
the UK who sold lathes that could turn external shapes better than it could
machine round, the process was developed by a German company called WERA
whose built machines to manufacture screwdriver, posidrive and philips hand
tools but found a market outside of their world. We used to install machines
in companies who used high speed sheet metal punching machines. The
principal is actually very simple and you all did it at school in maths,
take two gears of say 2:1 ratio and on the small mount the work piece, on
the larger gear mount two cutters at 180 deg apart, spin the work piece and
see what occurs. A square will appear. Under a precision measuring machine
the flats have a very slight radius but to our eyes no problem.
The video shows servo motors instead of gearing, it just needs to be timed
correctly.

Martin P
> Interesting video here:
>
[quoted text clipped - 5 lines]
> Regards,
> Tony
 
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