Block locating pin

Sometimes repairers add a pin through the back into the top block. I guess that this is done when the block, neck and ribs have separated from the back, though I would have thought that this was overkill and reglueing would be sufficient.  The repair pin here is the one on the center joint. the rib locating pin is the one cut through by the purfling. The advantage of off-setting the locating pin is that it is tricky to drill exactly through the center of the glue joint (witness the repair pin above) and it might be thought to weaken the joint. The choice is characteristic of the maker. Usually the second locating pin, on the lower block, is on the other side of the center joint, though on this 1780 example by Francois Pique both pins are on the same half of the plate!

The violin also boasts a button crown, double button pin and a surface patch, which hides the second pin.