Railroad spikes
The spikes worked perfectly. I followed the Deering installation video. Just needed a little adjustment to make it easy to slide the string under. Used Dremel tool with tiny drill bit at low speed. Marked the bit with a red Sharpie to get correct depth. Did 7, 9, 10 & 12th frets. Found the best spot for spike on frets with neck markers was just above marked toward the nut.