Osborne tool...what is it

[casemaker]

Anyone know how this is used?

[billybopp]

That is a channel groover.  It is used by cobblers / cordwainers to cut a slit in the sole of a shoe at an angle.  The "flap" of that slit is lifted up and sole sewn on with thread lying in that channel.  The "flap" is then glued back down over the stitches to make a smooth surface.    That one looks to be missing its blade, which seems to be a very common with these.

- Bill

[MikeRock]

Also used by an Amish harness maker in Albany, Wisconsin to make hidden stitch grooves on patent leather bridles, blinkers  and Scotch collars...  it was fun to watch and then try, on a hidden part. 

God bless

[billybopp]

Bruce Johnson has a few of these with blades intact ... https://brucejohnsonleather.com/leather-tools-sale/shoe-boot-making-tools/

- Bill

[jcuk]

Hi over here we have a tool called a Martingale Groover does a similar thing as these i use it for my rolled work to recess the stitches lovely old tool (H Brindley) think it was made around 1917 once stitched we use a burnisher or bone to hide the stitches.Here is a link to a video showing the process only she uses her blade from her clicker knife with a Martingale Groover it cuts out the possibilities of cutting threw the leather. 

https://www.youtube.com/watch?v=v2q6fRqGf5E

If the one you are looking at has no blade think you could fashion one from one of the snap off craft knives or a old hacksaw blade. Another link to Bruce Johnsons site same tool but he gives advice on its uses.

https://brucejohnsonleather.com/leather-tools-sale/stitch-groovers-channelers/

Here is a Martingale Groover

https://www.abbeyengland.com/abbey-martingle-groover-15.html

 

Hope this helps

JCUK