This is getting frustrating...
I typed out my response to the S&W, and then got booted off the system before I could press enter. Let's see if I can get it right this time:
For the S&W Revolver, besides getting a parts diagram, get the right size hollow ground screwdrivers. Regular screwdrivers can ruin the screw head and mar the gun, so get yourself some hollowgrounds. You may have to file the side down so it fits perfectly for the S&W screw, but that's OK as the screwdriver will serve you for a lifetime. Second, clean your workbench/table and sweep your floor clean. It makes recovering parts which enter orbit easier. Third, get a large cardboard box with tall sides. If you have a work mat, be sure it fits into the box. Cut out one side and now you've got retaining walls to keep parts from bouncing throughout the room. Also keep a good flashlight and magnet handy. Both help in finding parts. So, if you're not discouraged by now, read on.
1) Remove the grips
2) Remove the three screws on the sideplate of the frame. Keep the cylinder screw separate (it's the one on the lower right, ahead of the trigger guard and just beneath the cylinder). When you reassemble the gun, don't mix these screws up since it could result in sluggishness in opening or closing the revolver.
3) Do not pry the sideplate off. Rather, grasp your screwdriver by the handle (or use a hammer handle) and gently rap the grip. The vibrations will work the sideplate off the gun. Keep the gun near the table surface since you don't want it bouncing off onto the floor.
4) The hammer block probably fell out the same time the sideplate came off. That's OK. It belongs on the rebound slide (the large white metal thing which looks like a wood plane). You'll find a stub on the rebound slide which holds the hammer block in place.
5) Release the cylinder and pull it forward and off of the frame. The cylinder slips right off the yoke (or crane).
Now is a good time to study the action. Hold the gun in your left hand and work it in the DA mode. This is what you'll see:
Pressing on the trigger causes the nose of the trigger to depress forward. The trigger nose engages the "shelf" of the cylinder stop, causing the cylinder stop to depress downward, for which you'll hear an audible "click" and disengage from the cylinder stop notch of the cylinder; permitting the cylinder to rotate. The tail of the trigger cams upwards, causing the hand to rise, exit the window of the frame (milled slots in the frame which give internal parts access are known as "windows") and engage the extractor of the cylinder, causing the cylinder to rotate. Simultaneously, the tail of the trigger engages the DA sear on the hammer, lifting the DA sear which carries with it the hammer and causing the hammer to rotate rearward and compressing the mainspring. Meanwhile, the rebound slide is pushed rearward, causing the hammer block to slide down and out of the path of the hammer.
Continual pressure on the trigger results in the trigger nose disengaging the cylinder stop. The cylinder stop acts under pressure of the cylinder stop spring which causes it to pop upwards through its window and engage the forward leading edge of the cylinder notch (or on a police gun which is timed early, midpoint between cylinder notches). This is the other audible click you'll hear. The hand continues to push the extractor (counterclockwise), causing the cylinder to rotate such that a cylinder notch becomes engaged by the cylinder stop; arresting further rotation. The tail of the trigger continues upwards and the DA sear slips off. Freed from any retention, the hammer is urged forward by the pressure of the mainspring. The firing pin strikes the cartridge and you have ignition.
Releasing the trigger results in the rebound slide moving forward, which in turn forces the trigger forward. The rebound slide pushes on the seat of the Hammer, causing it to rebound backwards away from the frame. It also allows the hammer block to move forward and inbetween the hammer and the frame. As the trigger moves forward, it cams down and lowers the hand away from the cylinder's extractor and away from the window. The nose of the trigger pivots upwards, bypassing the cylinder stop and causing the cylinder stop to slip past. The trigger then comes to its position of rest just above the shelf of the cylinder stop. Simultaneously, the tail of the trigger reengages the DA sear and pushes it back. It then slips past the DA sear and comes to a position of rest just beneath the DA sear and above the SA sear.
6) Next thing to do is to detension the mainspring. You'll find a large screw on the grip. Loosen it such that the mainspring isn't tensioned and you can disengage it from the hammer strut and lift it out of the frame. Note: You don't have to remove the mainspring screw from the frame. Just loosen it such that you can remove the mainspring.
7) Place some pressure on the trigger such that you can rotate the hammer slightly back. This allows you to lift the hammer up and away from the frame.
8) Using a Philips Screwdriver (or any flat blade screwdriver which is ground to fit the small gap between the rebound slide stud and rebound slide spring), push the rebound slide forward and tilt the screwdriver up. Now, you want your free hand slightly above the rebound slide to keep it from popping out of the frame. It may hurt a little, but pain is good for the soul. Lift and remove the rebound slide and rebound slide spring from the frame.
9) Now, place a little pressure on the trigger and you should have enough space to lift the trigger and the hand away from the frame.
10) Using a small flat blade screwdriver, pry the cylinder stop up and out of the frame. You may have to compress the cylinder stop against its' spring a little, but don't twist the cylinder stop such that you'll bend the spring.
11) Turn the gun over and remove the screw for the thumbpiece. The thumbpiece comes right off now. Now, flip the gun over and remove the bolt. The bolt has a spring and plunger which provides it with tension. You don't want to send these parts into orbit as they can be hard to find. They're located in the rear of the bolt so what you want to do is to place a finger over that part of the frame where the rear of the bolt is. Reaching over to the left side of the frame, move the bolt forward (towards the muzzle) and push inwards. This will cant the bolt up and out. Do this slowly and you'll be able to stop the spring and plunger from launching into orbit.
12) The final part to disassemble (besides the sights which shouldn't be disassembled) is the cylinder. Sorry, that's state secrets and I'm too tired to type that.
Reassembly:
1) To reassemble, begin with the bolt. Replace the spring and plunger and tilt the assembly (front end first) into the frame. Keep a finger on the spring and plunger to keep it from entering orbit. Slip the tail end of the bolt down and into the frame. Secure it by replacing the thumbpiece and thumbpeice screw. Now, test it by snapping the thumbpiece back and releasing it. It should return sharply.
2) Replace the cylinder stop and cylinder stop spring. I do this by compressing the spring and then dropping the cylinder stop partially in. I then push the spring partially into place and slowly work the cylinder stop and spring into place as a unit. This prevents binding the spring (necessitating replacement).
3) Replace the trigger. Now, if you've removed the hand from the trigger, you'll have to replace it. There are two legs on the hand. One is the pivot leg and the other is the tension leg. The spring rests on the tension leg and provides the hand with the tension to move forward. To reinstall, I use a flat bladed screwdriver and push the spring leg upwards. I then slip the hand into the trigger and once the tension leg is in place, withdraw the screwdriver and allow it to come to rest on the spring. Test it prior to installation into the frame by pulling the hand back. It should snap forward smartly. Once you've got the hand back on, pull it slightly back and you can drop the trigger right back into the frame. Don't pull the hand back too far otherwise it will disengage from its spring.
4) Now, replace the rebound slide spring into the rebound slide (be sure you've cleaned and oiled the channel for the spring). Using a Philips Screwdriver, compress the spring and push the rebound slide down such that it mates with the rebound slide stud.
5) Place a little pressure on the trigger so that it raises the tail. This allows you to drop the hammer right into place such that the tail of the trigger is right between the DA sear and the SA notch of the hammer.
6) Replace the mainspring and tighten the screw.
7) Replace the cylinder.
8) Place the hammer block onto the hammer block stud of the rebound slide.
9) Replace the sideplate. Be sure that the hammer block channel fits over the hammer block and the lip of the sideplate can slip into the corresponding slot in the frame. You should not have to force the sideplate down. If you do, either the hammer block is not properly aligned to its channel (or it's slipped out of place) or the plate itself is not aligned to the frame's slot. Finger pressure should be sufficient to push the plate down. Replace the screws and be mindful that they return to their respective place!
10) Replace the grips. This should complete the reassembly of the revolver.
Good luck and post if you have problems. I'll get back to the cylinder later when I edit this post.