When I just brought the mill home, the pneumatic motor driven vari-speed adjustment worked well. Now it has become extremely sluggish and seems to hiss and leak a lot of air when working, especially badly when decreasing speed.
This is driven by this pneumatic valve:
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This seems to be a similar trouble to what I had with the brake valve. Probably some rotted seal. Unlike that brake valve, this speed valve has no markings. The procedure to fix it would seem to be to take it apart and see what went wrong. Before I do so, I wanted to ask for any suggestions etc about this, I would hate to fsck it up, esp. since I am not sure what make/model it is.
If anyone knows who made it, , I woud be really grateful.