I have a Dunlop plane that I have been using as a smoothing plane. Works well if really sharp. The problem, in use it goes out of adjustment with the blade backing out. The brass depth adjustment knob backs off allowing the blade to retract unless I am diligent about keeping it snugged up. I think the threads have too much clearance. I've tried tightening the cap screw, however, don't want to stress it too much. Thinking about putting a little paint on the threads. Any other suggestions to keep the knob from backing off? Bob