I am only a month or two away from trying my hand at rebuilding some valves in copper first on an old vintage trumpet with heavily worn valves. If it turns out well I will then set up for nickle silver plateing and hone the valves done and rebuild them with Nickle and then final fit. So at this point I am trying to collect relavant clearance information. Iread some place that Schilkes used to brag that his men fit the valves to .0004. In fact they had tried that but in practice did not do it because that was so tight that if the player so much as squessed the valve engine just a bit much the valves would bind. It did not though state what the final clearance was between the valves and the liners brazed into the valve engine! I would like to have a clearance to shoot for that is considered industry norm as oppossed to just makeing it up as I go! The alternative would be to build them up until they barley move with out binding and record the clearance then lapp them until they felt smooth and fast and record that figure. I might be helping a friend out with simalar work and more then anything I want to make sure I cross my T's and dot my i's so that if anything goes wrong it is with me and not while we are doinghis valves. So any information would be apreciated!!! Also who makes the best Reemer's or hones int he instrument industry? I like to buy the best tools I can afford so that I only have to buy them once. I cut my own rifle chambers but I normaly rent my reamers.