Park Tools chain checker and checking chain wear generally

dondon1 said:
What is all the fu..! compliant sh!t about which chain checker is more accurate than another chain checker and/or ruler. Trust your chain checker tool and just get one and use it.  Before you use your chain checker buy your self a new chain, take some measurements with your used chain and new chain and compare the results and make up your mind whether to replace it or not....The point is trust your chain checker maker...stop BS about which method is more accurate....peace out
I'm sorry that you're afflicted with your **** attitude. Maybe you'll get over it someday.
I have a new Park Tools CC-2 Chain Checker. It tells me my chain is worn to 0.75%, with a few strands at 1%, and <1% across the split link.

So I have taken off my old chain. Compared to the new chain, the stretch is half a link in 111 links. Which equates to 0.45% stretch compared to the new chain.

But the new chain also has some "slack". So the old chain is less stretched even than 0.45%. I measured the old chain against a 48 inch ruler. The stretch is 1/8 inch over 40 inches. Which equates to 0.31% stretch.

So I've bought a tool, and a chain, and spent time changing the chain, for the sake of, say, 0.35% stretch, when the Park Tool gauge reports 0.75% or more stretch.