I just spent a few hours attempting to adjust my clamshell strainer using the various tips in this and my previous (mis-spelled) thread. I have reached a few conclusions, some of which may be considered blasphemous.
There are a few things you can do to make the operation better, but in the best of situations I don't see how it is possible to get the CS to actually throw off as a normal strainer would. Most strainers move the snare wires vertically when the throw-off is operated, so that they drop out of contact with the head. The CS has very small vertical movement, and really just changes the tension in the wires as the lever is operated. There is some vertical movement, but it is very small. This is because of the geometry of the strainer motion. The crossbar moves in an arc. The combination of the radius of the arc and its orientation, that is nearly tangent to horizontal, makes nearly all of the motion horizontal.
It helps to work on it with the bottom head removed, then you can really see the relationship between the snare beds and the wires, but keep in mind that the presence of the head will change the clearance (obvious).
Make sure that both crossbars are free to rotate. If you use washers make sure they have a small enough OD so that they don't interfere with the rotation of the crossbars.
With the snare wires in place and the head removed, space the snare wires out enough to clear the snare bed. Check that the snare wires are paralell to the plane of the drum head (if it was there). Mine had a little twist that was remedied by loosening the screws holding the CS parts to the shell, adjusting the orientation and tightening the screws. I also moved the CS parts down as far as they would go to provide maximum clearance with miniumum washers.
On the throw-off side, adjust the jam nuts inside the drum on the lever pivot so that it is operating an the range that gives the most vertical difference between off and on. In either case it's nearly microscopic, but get as much out of it as you can.
Put it all back together and experiment with different number of washers. The "just clear the bed when off" seems to provide the best compromise. The final adjustment is to put the arm in the "off" position, and then play with the adjustment screw until you get a suitable compromise between "off" and "on" sound. I was not able to get a full "off" position that would get me a nice crisp snare sound in the "on" position. Find what works best. I just decided to not use this snare when I need a real "off" sound.
Make sure that you don't put a twist in the snare wires when you tighten down the snare wire screws onto the crossbars. As you tighten the screw down you want to get even tension in all the snares.
The Clamshell is one of the coolest looking strainers out there, but functionally it is something of an abomination. Did Krupa ever really play with one of these? I'll probably make an adapter plate and install a functional strainer, and keep the original one for showing.
Working with this makes me understand why so many CS drums don't have original strainers.
Please forgive my blasphemy.
