Thanks for the info.This has been noted by other users in the past.
Ko-ken 1/4 drive Z-series sockets/extensions/accessories may not lock into place when combined with off brand quick-release ratchets.
There's issues even using Z-series and standard Ko-ken socketry. Prime example is compatibility between 1/4 drive Ko-ken wobble-fix extensions with 1/4 drive shallow Z-series sockets. Because of the dimensions on the shallow Z-series sockets, it will not go to the "fix" position.
There are some quirks with the Z-series socketry stuff and I think the series can be considered a specialty series, that performs together as a unified system. The ratchets, on the other hand, are universal.
I did come across one other user's comments regarding the z-series not being an ideal fit on non z-series ratchets, but I didn't see anything regarding their regular sockets. I'm having issues with both (z-series, and nut-grip)...luckily, I only bought a couple sizes, and not complete sets.
Do you know if there are any other brand of ratchets (such as Nepros) that will work with the Koken sockets? The non quick release, and low tooth count of the Koken 1/4 ratchets is a major turn off for me.











