Drilling a square hole? Yes really!

[chevy2]

How about this one, you can how its done in slow motion.

http://m.youtube.com/index?desktop_uri=/&gl=GB#/watch?v=9orX-GmdVoc

 

[ronan]

I seen this a while ago and was amazed , what next ? Tartan paint or bottles of pidgeons milk ?

 

[langy]

How about this one, you can how its done in slow motion.

http://m.youtube.com/index?desktop_uri=/&gl=GB#/watch?v=9orX-GmdVoc

Gary you need to get about a bit more mate

 

[chevy2]

Gary you need to get about a bit more mate

I visited you today, where else should i go?

 

[langy]

I visited you today, where else should i go?

To the pub

 

[earthman]

At 8.50 in, the 'drill bit' is wobbling around a fair bit, I guess that this is essential to it's success.

 

[Ali]

Rotary broaching. Took me a while to get my head round too...

 

[stuvy]

Old thread resurrection

 

[grim_d]

Broaching is old hat anyway.

It's all about polygonal turning now.

 

[rtcosic]

Thank you, another fascinating technique, new to me! This CNC stuff is reaching the point where it challenges the limits of my comprehension!

 

[Hood]

Broaching is old hat anyway.

It's all about polygonal turning now.

Was going to give polygon turning a go a few years back but never got round to making up the toolpost/motor/drive for it and likely never will.
As far as I am aware however it is an external process, don't recall ever seeing it done internally and can't really see how it could be, do you have any info on internal polygon turning?

 

[earthman]

Rotary broaching. Took me a while to get my head round too...

It just doesn't look right does it, you watch it in action and think that it's got to form a round hole. Lol

I'm always interested in what can be done on a basic mill or lathe, sadly I don't have any fancy CNC etc.

 

[Hood]

You could do polygon turning on a standard lathe with a few adaptions, it wouldn't be dirt cheap though. What you would need is an encoder fitted to the spindle and then you would need a servo drive and motor to spin the cutter. The servo drive would have to be one capable of being set up as a follower or in other words be capable of accepting encoder signals for the command. You would then just set the electronic gear ratio in the drive to the required amount for your cutter teeth and number of flats you want.

 

[eLuSiVeMiTe]

Rotary broaching. Took me a while to get my head round too...

The Russian video isn't broaching.
It's drilling but the black cover over the Workpiece is guiding the cutter into a square shape. That's the wobble you can see in the shank.
A rotary broach spins and wobbles with the Workpiece to broach the square with a square cutter.

 

[grim_d]

Was going to give polygon turning a go a few years back but never got round to making up the toolpost/motor/drive for it and likely never will.
As far as I am aware however it is an external process, don't recall ever seeing it done internally and can't really see how it could be, do you have any info on internal polygon turning?

Nah not really It was tongue in cheek.

Not really polygonal, and I really don't know it's capabilities or limitations. Putting a hex inside probably not possible.

The "skiving" process is pretty nifty however.

 

[cheb]

That looks like a Reuleaux triangle, a three sided shape with constant width. 50p and 20p coins are a similar type but with more sides.

This will explain it better than I can: https://en.wikipedia.org/wiki/Reuleaux_triangle

 

[Maker]

You could do polygon turning on a standard lathe with a few adaptions, it wouldn't be dirt cheap though. What you would need is an encoder fitted to the spindle and then you would need a servo drive and motor to spin the cutter. The servo drive would have to be one capable of being set up as a follower or in other words be capable of accepting encoder signals for the command. You would then just set the electronic gear ratio in the drive to the required amount for your cutter teeth and number of flats you want.

Is there an advantage to this over live tooling? It sounds far more complicated and less capable.

 

[Hood]

Is there an advantage to this over live tooling? It sounds far more complicated and less capable.

Live tooling really needs a Y axis where polygon turning can be done with 2 Axis and a sync'd tool.