Stuff you have made today

[Tupers]

More shelves, you can never have too many shelves!

 

[Maker]

while the bar was still spinning

Polygonal turning? Very cool.

 

[m_c]

Polygonal turning? Very cool.

Yeah.
It's something that always fascinated me, but the main thing is, it now saves me a second op in the mill to create the flats.

 

[Country Joe]

I made a couple flats on a bit bar, while the bar was still spinning.....

How?

I've not really used a lathe since the 70's, (back at school) but they never covered anything like that - unless I've forgotten more than I realised!
At first I thought you were joking, as I'd assumed it would have to be done on a mill.

Having said that - I also suspected that @Maker was just joking too, whaen he referred to it as "polygonal turning"!
But now I'm swaying the ther way, and thinking maybe it was done on a lathe?

Mainly because this sounded less "jokey"

It's something that always fascinated me, but the main thing is, it now saves me a second op in the mill to create the flats.

All the Best,
CJ

In my defence, it is quite late & I'm quite tired!

 

[Brad93]

How?

I've not really used a lathe since the 70's, (back at school) but they never covered anything like that - unless I've forgotten more than I realised!
At first I thought you were joking, as I'd assumed it would have to be done on a mill.

Having said that - I also suspected that @Maker was just joking too, whaen he referred to it as "polygonal turning"!
But now I'm swaying the ther way, and thinking maybe it was done on a lathe?

Mainly because this sounded less "jokey"



All the Best,
CJ

In my defence, it is quite late & I'm quite tired!

It’s a CNC Lathe.

 

[Brad93]

 

[Nick DV]

Cool Excuse my ignorance, but is this possible on a 'non CNC' lathe?

 

[Hood]

It’s a CNC Lathe.

It can be done on a manual lathe, all that is required is that the rotating tool is geared to the spindle and that can be done with shafting or even an encoder on the spindle that feeds a servo drive that drives a servo motor which rotates the tool..

I had plans for doing it years ago but never got round to doing it as in reality it would have just been a project for the sake of it as I don't do the kind of work that would benefit much from it.

 

[Country Joe]

It seems to happen almost magically!
I think I'll have to hunt for a slow-motion version, to actually see what happens.

I'd assumed if it were possible, that the shaft would stop for as long as the first flat took to do, and then turn slightly for the next one, and so on - but as the tool-post is static, and also isn't a milling cutter, that wouldn't work, either!

Lathes must have moved on a lot, since my distant "experience" with them!

All the Best,
CJ

 

[Seadog]

 

[Hood]

All that is happening is the tool is synchronised to the spindle and thus it will pass the work and take a slice off it. It is not a totally flat surface but for most purposes it is fine.

 

[Country Joe]

Thanks, guys - it's sunk in, at last!
A bit embarrasing that it takes a cartoon to get the idea through to me!

Nice one!
CJ

 

[Nick DV]

Thanks, guys - it's sunk in, at last!
A bit embarrasing that it takes a cartoon to get the idea through to me!

Nice one!
CJ

You're not the only one! count me in on that too

 

[Country Joe]

You're not the only one! count me in on that too

Phew, thanks Nick - I feel much better knowing that!
I was starting to think I'd reached an age where I can no longer absorb info!

All the Best,
CJ

 

[Aff]

I've never quite understood the point of Polygonal Turning. On the machines I've seeing it done, it's always been a relatively slow process and the result is never that great (as you said the surfaces never come out that flat).

With live tooling there seems to be many better options.

@Hood Any reason you have chosen this process or is it simply a because you can and its cool?

 

[Kram]

Ive not seen that expained before, I assumed the cutting tool moves in and out rather than spinning.

 

[MBB]

The cutting tool spins as it s cutting, if it moves in and out that is done with a relieving attachment which is also geared to the lathe headstock.

 

[ukracer]

It’s a CNC Lathe.

So Maker was joking and my brain is not totally fried.
Edit. Maker was not joking. Lol

So it's almost like screw cutting..in that it's time and distance related.

 

[m_c]

I've never quite understood the point of Polygonal Turning. On the machines I've seeing it done, it's always been a relatively slow process and the result is never that great (as you said the surfaces never come out that flat).

With live tooling there seems to be many better options.

@Hood Any reason you have chosen this process or is it simply a because you can and its cool?

The flatness depends on the ratio, cutter diameter, and number of cutters. When I get time, I think I'll code a program to calculate and show the variations.

The reason for opting for this is for some parts I need the flats at the chuck end, which with basic live tools would need some form of long lipped/stepped cutter like a t-slot cutter, whereas polygonal doesn't have the same clearance issues.
To do the same job without polygonal would need a full Y axis.

 

[Hood]

I've never quite understood the point of Polygonal Turning. On the machines I've seeing it done, it's always been a relatively slow process and the result is never that great (as you said the surfaces never come out that flat).

With live tooling there seems to be many better options.

@Hood Any reason you have chosen this process or is it simply a because you can and its cool?

Wasn't me but usually a Y and C axes would be needed for live tooling to be of most use or at least much easier if you had them