The plate is ready to be sanded down and refinished. Before sanding, the agraffes are removed. I noticed while taking them out, it felt very tight to them turn up. There might be adhesive applied by the last rebuilder who may had a very hard time dealing with these little thingies. This piano has one agraffe insert and a large size (1/4") agraffe as repair from before. The rest are 7/32" in size. Oh, there is also a long-ago broken agraffe possibly from over tightening. The bottom part of that broken one is still in the hole. How to get it out? Hmmm. There are 3 way I have learned:
1. Put the top piece back on, use friction to turn the bottom up since brass is soft and can be easy to turn up.
2. Tap a sharp slotted screw driver in, then turn it out while hammering it down.
3. Drill through the bottom part with a small bit, increase the bit size and drill until a thin layer of brass is left inside the screw hole. The thin piece can then be easily chipped out.
4. Easy-out or screw extractor. Drill a hole for the size of the easy-out, tap in the extraction bit, turn it counter clock wise by hand to extract the broken brass bottom. This is the last solution. Easy-out can do big damage.
The first two methods failed. The adhesive in the hole is very strong. I started to panic, skipped method 3, used a small easy out for the very first easy-out-trial in my life. Failed, almost broke the thin extractor bit. Fortunately, the drill bit used just now is very thin and the drilled hole is just in the center of the broken bottom. I gradually increased the drill bit size to enlarge the hole on the brass agraffe bottom, but not touching inside of the screw hole on cast iron plate, as shown on left picture. The final drill bit used is size 15 (.180") for that 7/32" agraffe screw hole. The thin layer of brass still doesn't want to peal off. We happened to have some taps just for the agraffes. The top part of the broken agraffe is out and the top part of screw hole without any brass residue. The tap is able to be turned counter clock wise to sit solidly in the screw hole, not to cross thread, then it is slowly turned clock wise with downward pressure. Graaaadddduuuaaaly, the brass residue is tapped out and screw hole clean. My goodness. The tap size is 12-36.
Just to be sure, an 7/32" agraffe is turned down to see if it is loose or if this screw hole can be saved. It is tight! Here is some advice from my good friends:
1. Heat can be applied to help loosen up the adhesive, either glue, epoxy, or some liquid tightener.
2. Do use easy-out as the last solution. It can do damage.
3. Before drilling on the broken bottom piece, punch at the center for drill bits to bite on.
4. The boss decided to use agraffe inserts for the new agraffes incase the old screw holes has flaws.