Strange Bit

[rusty]

Strange little oddity I have never seen before. I would have called it a forsner bit, but it has no point.
Very small....and won't go very deep.
For inlay?

(Ed: It has a chisel edge inside, it doesn't show very well in the picture)

[Branson]

Looks like you'd need to start a hole with one bit, and then use this one for depth.  It doesn't look like it is limited to the size of the working end.  Can't see it for inlay work.  Could be for chair making maybe.  When you're drilling mortices in the legs for the rungs, the lead screws on auger bits tend to
burst through the other side if you get the depth you want. 

[mrchuck]

Maybe a "plug cutter"?

[rusty]

It won't cut a plug, because the chisel edge inside will eat the plug. I was thinking of plugs when I looked at it because of the diameter, but it's useless as a top reaming tool as it has no point to guide it.
However I think Brandon's idea is probably correct, a hole bottom finishing tool , so you get a nice flat bottom on your hole. Saves risking going through the wood with the drill by trying to drill right down to the very last little bit of wood before breaking through...

[couchspring]

forstner bit

[jimwrench]

Agree its a Forstner bit. Patent Feb 23,1876 Mine has a very tiny nib that only protudes maybe 1/32 past bottom face of bit.

[Bill Houghton]

It is an odd design; not sure how you'd get it started.  Maybe you need another bit to start the hole, followed by this to finish it.

I've found so many strange bits out there...designs that seemed genius to the person who developed them, but not by the market.

[mikeswrenches]

I have a 5/8 and a 1 in.  The 5/8 has patent dates of 9-22-1874 and 2-23-1886 which corresponds to patent no's 155,148 and 336,709 respectively.  The 1in. Only has the 1886 date.

Both were issued to Benjamin Forstner.

Mike