Vertical shear finishing tool for the lathe - video

[Jon]

Vertical shear finishing tool for the lathe. By Steve Jordan. 9:31 video:

[NortonDommi]

I have a couple of those Eccentric Engineering tangential tools and find they do an excellent job as a shear tool when used in reverse i.e. with a RH tool instead of running towards the headstock cut towards the tailstock and vice versa for a LH tool.
The bit could also be turned through 90 degrees to achieve the same result, I have been means to make a dedicated tool though.

[old_toolmaker]

Nice video and post!
I figure I am eccentric enough to make my own. So I did, but I seldom use it.
Thanks for posting!

[Floradawg]

Vertical shear finishing tool for the lathe. By Steve Jordan. 9:31 video:

Great info. Is the traditional cutting speed the same for this tool? Thanks.

[andrew mcgregor]

Vertical shear finishing tool for the lathe. By Steve Jordan. 9:31 video:

Hi Steve. Do you have any thoughts to share about the sensitivity of the finish to different speeds and feed rates? In your examples you look like you're turning at quite a low speed but moderate feed rate.

Regards

Andrew

[tonyfoale]

I have a couple of those Eccentric Engineering tangential tools and find they do an excellent job as a shear tool when used in reverse i.e. with a RH tool instead of running towards the headstock cut towards the tailstock and vice versa for a LH tool.
The bit could also be turned through 90 degrees to achieve the same result, I have been means to make a dedicated tool though.

I made an indexable carbide tip version by machining the sides of the tool holder to 15 deg. There is a full description here

Shear tools for lathe work.

Click image for full size.

[Hans Pearson]

The shear tool is extremely useful for obtaining very close tolerance finishes, down to exactly on size.

[Toolmaker51]

One could create a formula, though a clear method escapes me. Perhaps recording of result is a better term.

Any rate, shearing differs from conventional turning that periphery and cutter are close to alignment, instead perpendicular. Spiral of chip shows that, something (barely) like a drill bit.
The lowered speed, high feed is a low temperature cut; transverse cut engages marginally wider area like deeper cut with radius tool. The finish might improve lowering feedrate more, with a diminishing return.

Job shop wise, we ground the bits on a surface grinder, stoning the leading edge. Without access to a rubber roll grinder, this worked on feed spools, like no perpendicular might.

[Bony]

I noticed some chatter whilst turning that you quickly averted. That suggests to me either a lack of rigidity (which doesn't seem to be the problem) or that the tool bit is no longer cutting but simply rubbing, which of course needs to be avoided. Any comments?

[old_toolmaker]

In my own experience these vertical shear tools don’t do a good job of turning to a square shoulder. Am I expecting too much of this tool?