Because the iris normally protrudes (aka referred to as High Dome or High Lens) in glass eyes, its necessary to make a pocket for the lens to set in, to prevent the eye from rocking sideways or having large gaps. The general rule for beveling is to use a beveler the size of the eye, one size up and one size down. For a 20mm eye, I would gather up my *24mm, 22mm(one size up), 20mm(the size of the eye when in bisque form) and 18mm(one size down) bevelers, and a 22mm glass eye for sizing purposes. (*I normally go TWO sizes UP so that I can remove the excess from the corners of the eyes when using paperweight eyes
Its always best to have a size larger eye than what you are going to set in the doll, i.e., if the tech sheet calls for a 20mm glass eye, you need to have use a 22mm eye for perfect sizing. Always use the same brand for sizing and setting, since each manufacture's lens vary.
Lets us 20mm for as an example.
Knowing that I have to set a pair of 20mm eyes in the doll head. The doll's head is softfired and about the thickness of a nickle. The head should be soaking in water.
Score around the entire eye blank 4 or 5 times. Pierce a large hole in the center of the eye so that I can see the beveler. I begin by using a wet stone 24mm beveler and make 6 complete turns.
Next I take a 22mm and make about 12 complete turns or until I see the corners of the eye wearing wearing down by the beveler. (Always keep the stone beveler and the eye WET and watch the corners, as they usually thin out first). Take a utililty knife and cut away the remaining piece left in the socket. Now continue to bevel with the 22mm until all the debris is beveled away and the eye rim looks uniform.
VERY CAREFULLY place the 22mm glass eye in the opening and see if the rim is even and if the eye is beginning to fit, if it is, then take a 20mm beveler and JUST BELOW the LOWER RIM (not on the rim!!! Keep the beveler positioned BELOW the rim) bevel in ONE DIRECTION only, as the eyes are getting thin.
Now VERY CAREFULLY fit the 22mm glass eye into the socket. Bevel one or 4 more times (in one direction only! -- aka half turns) if necessary with the 18mm beveler. When you drop down to the last size, IT IS IMPERATIVE THAT YOU KEEP AWAY FROM THE RIM..... or you will have an uneven cut, and worse yet, the rim will CHIP!!!!!!
Wooden eye bevelers will eventually wear down and lose the full round shape, or they may swell and warp (as wood does in water) Its wise to invest in good stone bevelers.
Let the weight of the stone bevelers do the work for you. Don't push or press hard into the eyeball socket, as it can cause the entire face to crack.
Remember to keep the eye and the beveler wet, for a smoother rotation and less chance of eye chipping.
Use a soft bristle brush to gently smooth the rims and corners when you have finished beveling.
Wear your Optivisors and always have good lighting.
Happy Doll Making!