I have another auction item I have no idea what it is. I got it with a group of leather working tools, but not sure what it is. Handle looks like a file handle and it has a moving piece in center. Made by "Mabsco".

You aren't the first who has wondered, there are several other threads I found stumping people.
The most sensible guess I have seen so far is a calking removel tool. The only product I was able to find for MABSCO was some kind of plastic nautical calculator, (MABSCO Products co, Flushing,NY)

Another one:
http://img.photobucket.com/albums/v80/harnett65/Album%205/v90.jpg

http://www.ebay.co.uk/itm/Mabsco-Caulking-Removal-Tool-11554-/160676706180?pt=LH_DefaultDomain_0&hash=item256913f784&ssPageName=RSS:B:SHOP:GB:101

The Ebay one does say Pat Pending , so there may be a patent somewhere....

That must be some HEAVY caulking! Maybe caulking on a boat or ship. Or maybe the caulking that goes in cast iron waste plumbing pipe?? I am still not sure. Thanks for your research.

It does not look like any leather tool I've ever seen.

I was going to say reefing hook (caulking remover)   Ship and boat work.

I recently found an almost identical tool. The only difference is that mine has a patent number 2,827,697 (1934-5). Showed it to numerous people, only one thought it might be nautical.

Patent No. 2827697 does looks like it.

"Patented Mar. 25, 1958

2,827,697 SEAM REEFING TOOL Leonard F. Woodel, Hollis, N. Y. Application April 5,1956, Sena! No. 576,459 2 Claims. (CI. 30—293)

The present invention relates in general to seam reefing tools, and more particularly to hand tools for raking calked joints in decking and sides of boats and the like preparatory to recalking joints.

http://www.google.com/patents?id=zklQAAAAEBAJ&pg=PA1&dq=2,827,697&source=gbs_selected_pages&cad=2#v=onepage&q=2%2C827%2C697&f=false

Very good, a drawing! I guess the moving center piece is either a depth gauge or stop, or maybe a fulcrum for prying.
Thanks for the info!

The patent describes it as being used as a depth stop, so that the calking can be pulled out while leaving the oakum wicking still wedged into the groove between planks of a ship's hull.  The two tips differ in thickness (width), so as to suit different grooves between planks; the moveable arm can be set adjacent whichever one is suited to a given groove.