I found these three items that seem to be a set or part of a set, but of what?  There are three sizes.  The threads are 3/4-16, 7/8-16, and 1 3/16-16.  They all have an inverted cone in the threaded end and two flats.  They were in a machinist box that had been picked over, but most of the remains were related to machine work.  The heavy equipment repair stuff was in the lower roller cabinet, but there was some mixture.

In Skips thread, he shows us a GOOD axle puller. I think that yours are the cheaper alternative. You thread them onto the end of the axle and then caress it with a 3 pound hammer. Sometimes the drum comes off and sometimes you ruin the threads.

http://www.papawswrench.com/vboard/index.php?topic=5661.0;topicseen

I'm thinking more like a cap for hydraulic lines or something on that order.

John, they are not axle "knockers" because they have male threads.  Unusual male theads, since they all have 16 threads per inch, which is very fine for the 7/8 and 1-1/4 inch sizes.

Lewill2, they aren't hydraulic plugs because the thread size doesn't match any known hydraulic fitting threads - same reason as my reply to John.

A bigger photo is attached.

looks like it's to plug off a fitting when you remove a hydraulic line.

It sure seems like a bull plug for a higher pressure line - hydraulic or not

Anyone recognize the extra-fine threads as noted in my earlier posts?  I could see this being a cap/cover/plug for a hydraulic valve body.  I doubt it is related to hydraulic fittings since it does not match any known hydraulic fitting thread size.

Perhaps magneto pullers for small engines or motorcycles. Used to use similar on small Japanese bikes.

Quote from: Papaw on September 03, 2012, 11:34:09 PM
Perhaps magneto pullers for small engines or motorcycles. Used to use similar on small Japanese bikes.

I looked on Google Images and found the closest thing was a motorcyle flywheel puller that had a bearing ball in the end.  These have no forcing screw and the threads are so short I don't believe they could pull a flywheel. 

They are certainly factory made.  I just can't figure out for what.

Some of the flywheel pullers just thread in to stop against the shaft, then a hammer knock pops the flywheel off.

That round circular area in the center is for something like a puller to fit into, it's a dry bearing surface, I'm thinking the back end of some special puller assembly (like a pully installer/remover?), or a punch backing piece...