Diy Valve job
And don't for get the bounce spring!!!!!!
Broke too many stones before i figured that one out.
finessing a perfect round and sealing seat takes some practice.
Get a junk head and have some fun!!!
If you have someone that's done this before, the learning curve will be much shorter.
I finally had someone show me it was the operator not the tool that was bad............finally got valves that would hold water:D