Producing Concave Surfaces With A Vertical Mill

[randyc]

you know what...we can debate this forever...I give up

I hope that I didn't offend you - I certainly didn't intend to ! You pointed out an important point that I'd missed (about having to tilt the mill 90 degrees to produce a true spherical surface) and I was attempting to also make a correction, not to be argumentative.

randyc

 

[Billh50]

No problem......My only thing as simply as I can put it was that an ellipse is nothing more than a stretched circle where as a parabola would always be open and never closed. And if you look horizontally at the bottom half of the cutter you will see a parabola and if you came up with the part the sides would eventually be straight so would not create an ellipse.
I know it is hard to explain on here so I am just not going to try anymore. But am not offended at all. Everyone has their opinion on things and sometimes it is hard to explain well enough to change them.

So anyway,
how's your day going?

 

[randyc]

You're right - everyone has an opinion and the rest of us should respect it. I believe that you and I have reached that point and there's little point in continuing so peace, bro

My day is going OK. Since my wife died two months ago, I've had very little ambition to get out in the shop (or do anything, really) but I'm determined to change that and it was this thread that stimulated me, LOL. I have a short, simple lathe project in mind that I'm going to document and post.

Thanks for asking !

 

[Billh50]

Randy I can sympathize with you about your wife.....my first wife died 19 yrs ago this past valentine's day. not easy to loose someone.

 

[chips&more]

ScrapMetal, that's the classic example I was taught with in high school drafting except that you can't obtain a hyperbola from a conic. A hyperbola is two curves that are mirror images.

IMHO, Scrapmetals example of a solid angle with its identified cut-outs, i.e.; the hyperbola, is in fact a hyperbola…Dave.

 

[randyc]

What an awful, awful day to lose a loved one !

(Joyce died of cancer, both my parents died of cancer and I have cancer although I'm in remission. I always thought that I'd go before Joyce because I was 12 years older. Sometimes I get angry about this but then I'm grateful for the time we had.)

Thanks for your empathy -

 

[randyc]

IMHO, Scrapmetals example of a solid angle with its identified cut-outs, i.e.; the hyperbola, is in fact a hyperbola…Dave.

Nope, see this (or do your own search for a hyperbola). The example Scrapmetal depicted was two parabolas of different size.

http://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0CAcQjRw&url=http://www.intmath.com/plane-analytic-geometry/6-hyperbola.php&ei=1BfpVMvCL8KcNuregYgG&bvm=bv.86475890,d.eXY&psig=AFQjCNHigU2wn236zyqj-TwhNWWtR0uurA&ust=1424648530985348

Scroll down far enough in the above link and you'll find that a hyperbola requires two cones stacked together to be able to achieve a "sliced" cross-section with the correct configuration.

 

[Billh50]

My wife died of a strain of viral pneumonia that caused her lungs to fill with fluid so fast she couldn't breathe. I found her too late to help and it hurt for almost a year. But then I realized we had had a great day that day and she was happy just before it happened. And life does go on for the rest of us.

 

[randyc]

My wife died of a strain of viral pneumonia that caused her lungs to fill with fluid so fast she couldn't breathe. I found her too late to help and it hurt for almost a year. But then I realized we had had a great day that day and she was happy just before it happened. And life does go on for the rest of us.

That's a bad way to go and will be my demise as well. One lung has already been removed (I have non-small cell lung cancer caused by chemical exposure when I worked in the semiconductor industry - I'm not a smoker) so it's difficult to exert myself already.

I'm so sorry about your wife. It's been many years but I'm sure that there are still times when you feel the same pain as you did then.

My wife's parents and I were with her when she went. She was dozing off and on and then she just didn't wake up. Here we were on our wedding day. I keep this picture in my living room so that I can look at her every day. She was so beautiful and so happy ... Need to make a frame one day.

 

[brav65]

Guys I think you are missing the point. It's all ball bearings today... Now get me some gauze pads and 3 in 1 oil so I can check it (Chevy Chase in Fletch Lives) ;-)

I posted this before I read about your wife, sorry for your loss.