Hi,
Davis locks often have weak main and frizzen springs. I've never seen a Davis lock spring as badly finished as what TDM shows. It is outrageous that someone would sell a lock with a spring like that. The "colonial" lock I used worked pretty well right out of the box but I improved it a lot by strengthening the mainspring and tuning the lock. The frizzen spring was too stiff and the the surface under the toe of the frizzen so rough it felt like you were rubbing the frizzen over sandpaper when you opened it. However, the basics of the lock were good and all those annoying features readily corrected to produce a very reliable and smooth functioning lock. These are not Chambers, Kibler, or Laubach locks and they have to be worked over to bring them up to a similar standard.
dave