Non-Pentax adapters are a reasonably priced alternative if you intend to remove the spring & leave the adapters on lenses.
The main difficulty is that such adapters can sometimes be over-rotated when mounted and make straightening things out a chore - not impossible, just time consuming.
This problem can be easily prevented one way or another.
(1) Be sure the adapter "ears" nearest the red dot do not have a rounded fillet. Use a little file to square the junction. Original "Pentax" adapter on left:
(2) Drill an indent in the lens base so it'll be held in place by the camera's locking pin.
- mount the lens & put a pencil mark on it where the locking pin hits the base. Drill there.
Of these alternatives, I prefer (2) as it firmly locks the lens in place so it will neither over-rotate nor fall off. This is true for both genuine Pentax adapters and knock-offs.
Iowa Dave
PS I don't recommend gluing the adapter threads to the lens. It'll stay in place with friction and someday you may want to remove it.