Removal and upgrade of Blow off Valve studs on Loco Boiler manhole cover. I show how I removed the seized studs in the old manhole plate, discuss the Black books and the Hot Sheet for threads. I show the small square I use for checking that the thread tap is 90 degrees to the plate. And discuss the problems with old plate. I also note that our Machining You Tube Creators need you help in purchasing our shirts to support our teachings through our You Tube channel.