Hi bikeforums, I'm a beginner with all this bike stuff and this is my first post so please be gentle...

My 8 speed screw on shimano freewheel's sprockets are extremely worn, and I bought a cheap off brand replacement from ebay as a stop gap. The replacement went on fine, but within a few days the cogset would turn without turning the wheel and after removing it, noticed that the thread had stripped on the inside! A bit annoyed as it cost me £20 but you get what you pay for (unless I cross threaded but was very careful about that).

The actual rachet mechanism + screw on thread on my old freewheel is in great condition, so I want to get the cogs off the old freewheel and replace them with the cogs from the first one. Only thing is I can't find any consistent information about how to do this (and if it is even possible on my cheapo freewheel). I've read Sheldon Brown's pages but it's all a bit of a mystery. So far I've pieced together that I need to secure the largest cog in a clamp or vise, and use a chain whip counterclockwise to remove the smallest cog.

Before I go and buy a chain whip and waste a few hours in the garage, is it be possible to disassemble the freewheel in this way (picture below)? Is it likely that the cogs will be interchangeable?

Here is a picture of the freewheel: http://imgur.com/yR6Gccq