Unusual cutoff tool?

[fcs]

I was randomly watching this short Clickspring video

and he used a cutoff tool (at about the 40 second mark) that was angled at the business end and possibly curved. It goes by so fast its hard to get a good look. Can anyone tell me what the tool geometry is and its purpose?

 

[graham-xrf]

I speculate, but thinking it through, that is a very small part!

Going at it with a conventional width parting tool might have bent it out of shape into an early collapse, just from the tool cutting pressure.

Using the parting tool shaped at an angle keeps a strong cone forming on the left, so that it stays whole while the point, being at the deepest place to the right, still parts it off at a very tiny nub.
.

 

[woodchucker]

That's to create the chip, and make it roll tight and at an angle, which makes the chip break as it hits the face of one of the sides.
The angle is to remove the part leaving no nib on the cuttoff piece. The next piece needs a facing.

 

[homebrewed]

I sharpen my parting blades with a slight angle so the piece I'm making parts off cleanly -- no need for a second facing step to remove the nubbin (particularly useful if you're making relatively thin washers or spacers).

I've seen some folks advocating grinding a V or U profile on the top of the parting tool, supposedly to create a chip breaking action, but I haven't found that necessary.

I don't recall where I learned about creating that angle but it's worked well for me. I haven't noticed the tool cutting an arc, but I keep the parting blade's stick-out to the bare minimum needed to do the job.

I used my parting tool less than an hour ago. A quick touch-up with a 600-grit diamond grinding stone and it cut my 6061 aluminum cylinder like it was butter

 

[mikey]

I'm going to guess that its just a graver.

 

[ahazi]

I was randomly watching this short Clickspring video

and he used a cutoff tool (at about the 40 second mark) that was angled at the business end and possibly curved. It goes by so fast its hard to get a good look. Can anyone tell me what the tool geometry is and its purpose?

You can slow down the playback speed on YouTube to 0.25 and get a clear picture.

 

[fcs]

You can slow down the playback speed on YouTube to 0.25 and get a clear picture.

I never knew you could do that! Opens up a whole new world I never knew existed. I’m serious.

Is there a name for that tool shape? I make a lot of small parts and it looks like something I will try to grind.

 

[graham-xrf]

I never knew you could do that! Opens up a whole new world I never knew existed. I’m serious.

Is there a name for that tool shape? I make a lot of small parts and it looks like something I will try to grind.

I have some "names" for some tools I have attempted to grind!
Let's not go there..