Hi, I have a spinning recliner chair that i am hoping to modify. Trouble is, i can't seem to work out how to remove the swivel from the base. Not too sure what mechanism is in use, but there seems to be too much friction to indicate bearing use. The point of attachment looks similar to the old shimano sealed bracket tools, also, the inside tube has strange "predator" tri marked grooves set into the end. I have included a couple of photo's, so if anyone can throw any light on how this can be taken apart, i would be extremely grateful 
View from underneath:
View from side:
View from underneath:
View from side:
