Stupendous Man wrote:

Add these to trevors' responses,

These are some of a dozen or so, ground from rod stock and honed. I have
no idea what they were made for. They are ground to the centerline and
have no relief angle.
http://i221.photobucket.com/albums/d...e/IMG_0877.jpg

I've seen similar cutters used to trepan rubber, and in with tramels to
cut gaskets, I think the points might be to blunt but engraving is done
with similar tools also.


This one has some pretty serious angles on it and has a very thick
carbide. I can't figure out what carbide-worthy material needs so much
relief.
http://i221.photobucket.com/albums/d...e/IMG_0884.jpg
http://i221.photobucket.com/albums/d...e/IMG_0883.jpg

I first thought this was a boring bit by the angle of the top rake, but
the second picture shows side rake (not normally used for brazed boring
bits). I have seen similar brazed bits on old large face milling cutters.


This one has a cutting edge about 5 inches long, again no idea what you
would cut with it. It really is a blade more than a single-point, and
agin, zero relief.
http://i221.photobucket.com/albums/d...e/IMG_0881.jpg
http://i221.photobucket.com/albums/d...e/IMG_0883.jpg
http://i221.photobucket.com/albums/d...e/IMG_0880.jpg


I can't see the back side, but if the tool is ground 1/4 around with a
flat top and a flat back with about 5-7 degrees front clearance it would
be used to trepan face grooves with a lathe (and by the length of the
business end the user would have much bigger stones than I do).

Matt