The Framers Forum

I have not used my underpinner for a while and now I have two problems - unrelated or not? The wedges are not being driven right home, (using obeche), and I am getting a horrible clang intermittently. I've looked at the workings and I see an angled metal block which seems to act as a cam for the mechanism that pulls down the workpiece presser. I can see a wheel that should roll smoothly on the angle piece but it has gone past that onto a vertical surface. When the pedal is pressed it has difficulty getting past the sharp corner onto the angle piece. Can any one advise what I need to do to get it operating smoothly and driving the wedges right home?