Thread: Tangential Trickery

Hi Toolman,

What sort of results where you getting on the blackbar using the D.T in the normal way? Cause the results your posting are great. I've got a D.T but can't get anywhere near that finish with blackbar (though the stuff I'm using is really horrible).

Ben

Hi Ben,
The end of the material held in the chuck was turned with the normal tool setup.
Regards.
Martin

You can get the same effect with a normal toolbit, ground and presented to the work in a similar way.
With soluble oil coolant and low speed, I was shown (North Sydney TAFE, night course, 1980s) how to do this to get a very clean finish, suitable for running an oil seal on, without need for grinding afterwards.
The arrangement isn't sensitive to tool height adjustment, as there's always a point along the sloping front tool face that is at the correct height.

Jordan

Hi Martin,

Thought I'd show my efforts at turning black bar.

Bear in mind this is welding/structural bb (I only use it because I got a heap of it for free).

The photo DTH shows the turned BB. The finish at the headstock end is turned by the DTH with a Crobolt piece, the other end is by carbide.

Ben.

Here is a link to "The Contrary Ground Finishing Tool" which explains a little more about the angles.

http://d.yimg.com/kq/groups/2573836/...FinishTool.pdf


I have ground this tool and used it for years. It gives a nice finish when used with a very slow feed.
Hadn't thought about turning the tool around in my DTH. Must try it.

Michael.

Originally Posted by triton2

Here is a link to "The Contrary Ground Finishing Tool" which explains a little more about the angles.

http://d.yimg.com/kq/groups/2573836/...FinishTool.pdf


I have ground this tool and used it for years. It gives a nice finish when used with a very slow feed.
Hadn't thought about turning the tool around in my DTH. Must try it.

Michael.

Thanks Michael,

I wasnt understanding this concept at all until I saw the last picture in your pdf file.

Its all very clear now.

Bill