Royce, Based on my experience in the compressed air industry, I would suggest the following:
The valve block surface and the valves should be finally finished with 1000 grit on a properly precision machined steel plate , then on a piece of "real" plate glass using a very light lapping compound such as bon-ami, to the extent where a high polish (like a mirror) is obtained indicating that there are no scratches or burrs. The parts should be moved on the glass in a figure eight movement, preferably to a back and forth or circular movement. This will help insure that the surface of the parts are polished evenly. Intensive washing of the parts to remove all the abrasive materials and metal is essential when all is done. Before all this make sure the ports are clear of burrs and wash thoroughly--you don't want chips of metal to be around as you start the lapping procedure. Geoff. Hi Phil. Thanks for responding to my dilemma. On initial installation, >I think I hit the valve face and port face with 600 grit wet or dry & >oil before the first run. But I didn't break the sharp edge on the >bottom of the valve. On the first run, it may be that the assembly oil >( read that turbine oil) may have run "dry" (although I would be >surprised if that happened within 5 minutes of running). However,the >scratches (which I am assuming are the result of galling) reappeared >after removal of the inital scratches by re- honing. The plans call >for both parts to me made of brass, so I am beginning to think that >there is a problem with the "bronze" that I used to make the valves. > Some impurities may be causing the problem. > >royce in SB > >Phil Paskos wrote: > >>Hmm. >> If the materials are finished well, no sharp edges etc and you're using >>steam oil that is getting to the ports, I'm surprised that is happening. >> >>Phil P >> >> >> > >
