If the knives are opening properly with the flipper and you are having difficulty opening them with the thumb studs, then there is a technique problem. The issue I have seen most people have with using thumb studs on assisted knives (particularly the ones where the studs lie close to the frame when closed) is that they are trying to push the thumb stud away from the handle of the knife at a 90º angle to the long axis. It takes a great deal of effort to overcome the torsion bar and get the 30º necessary to get the Speedsafe to kick in. Additionally you tend to follow through on the thumb stud, increasing the chance of cutting yourself.
I find that it is much easier to slide your thumb forward along the scale so that it slides between the frame and the stud. Continuing forward will open the knife with very little effort. Care must be taken when using the studs to not obstruct the rearward movement of the flipper. In some grips that position your thumb for the studs, your index finger can keep the flipper from moving or at least slow it down and keep the blade from locking open.
A while back I illustrated this using a Spec Bump when someone had the same complaint.
In the second picture, you can see the direction I am actually sliding my thumb. One of the great things about this technique is that your thumb never leaves the scale.
If you are wondering about the second arrow, in most Speedsafe knives with flippers, you can position your index finger that way and just squeeze to open the knife.
If you are doing it right either way, your fingers and thumb barely move, it almost looks like the knife opened itself.
Before anyone asks I confirmed both methods work perfectly on my 0350 and 0301 as well.
