Step 1 is to get the bolt head to fit the notches. You can do this by sanding the "off side" (all of it . . . right side (tall side) or the left side (since you should thin the left side arm). Either way, the bolt head has to fit into the notches. After that, the left arm should be reduced to at least half its thickness (from the inside). You WANT IT to flex . . . saplings bend, Oaks break . . . if it's a new Uberti bolt, the left arm is already thin enough (just like the originals).
( * correction* !! I fit the bolt head by reducing the whole side because I install a fitted bolt block. If you're not going to install a bolt block, just thin the area immediately in line with the bolt head and on the left side only . . . the right side needs to locate against the frame.)
Before continuing, check that there is a "return bevel" on top of the left arm. This bevel allows the cam to push the arm to the side and get back under the bolt arm as the hammer falls. I point this out so that during the "timing " process, that bevel needs to be maintained.
Step 2 check that the radius cut for the cam actually clears the cam. This is called "reset". The cresent cut at the rear of the left arm is where the cam locates. If needed, this cut needs to be opened enough to allow the cam to " locate" when the hammer face breaks the plane of the recoil shield or just after. This is important because letting the hammer down on a live cap on a loaded chamber without "reset" occurring means your revolver is locked-up and dangerous!! . . . to everyone!!
Step 3 timing the bolt drop. The 2 surfaces involved will be the rear most vertical surface and the top horizontal surface. The rear most dictates how far down the bolt head descends into the frame. Removing material from the top most will determine when the arm falls off the front of the cam (NOT slide off the side of the cam like you may hear on some YouTube vids . . sheeeesh!!). So, to keep from over stressing the bolt spring side of the combo spring, the bolt head needs only to descend even with the "water table" of the frame. Any more than that puts undue stress on the spring (with torsion springs, it doesn't matter). After you're happy with the bolt descent, the top surface can be reduced (staying parallel with the very bottom of the bolt proper) to achieve bolt drop. Ideally, the bolt should drop a bolt width before the locking notch ( in the approach(lead) if one is available).
This is assuming that the hand is the correct length which will give you simultaneous lock-up of the cylinder at full cock (sounds like a single click). If this is in question, correction/confirmation of this needs to occur before timing the bolt.
Correct action setup will give 3 audible clicks (1/2 cock, bolt drop, full cock ).
Or women.
