Sorry, new to this. Hope this works this time. Anyone know what this is?

[oscarfelix]

[gibsontool]

h If it pivots it could be a home made bevel square?

[mvwcnews]

Given the size (if that is a standard door in the background) -- it would give you enough leverage to pick an empty wagon or carriage axle up off the ground  for axle lubrication -- you'd need two people (one to hold the "jack" & the second to do the actual lubrication work).

[turnnut]

for a wagon jack, it should have a base plate.

also a notch at the contact point so it does not slide or shift on the undercarriage.

and yes, as was mentioned, a means of locking in position.

??? unfinished project ???

[Billman49]

French waggon jacks often look like this - no base plate if used on a hard surface, e.g. a cobbled yard...