Brewgyver:
Filling and drilling can result in enough off-center error to cause serious problems.
Well - you just gotta be a bit smart about it:
- Find the diameter of the hole, then find a drill or piece of steel rod that matches hole (hopefully it is a standard diameter)
- Mount said drill in drill press (verify that drill press table is square with chuck)
- Put a piece of wax paper over a piece of wood and clamp or otherwise afix it to the drill press table
- Bring the rod down to pass thru the center of the encoder disk until it touches the wood/wax paper; lock the chuck position in place
- Clamp or otherwise afix the encoder disk to the the wood so it can't move
- Unlock and raise the chuck/rod - remove the rod from the chuck (be careful to not disturb the position of the wood/encoder/table, etc)
- Fill in the center of the encoder disk with the epoxy (again, be careful not to disturb/move anything - if you've clamped things properly, this shouldn't be an issue)
- Once the epoxy is fully cured, put a drill the size (or slightly smaller for a press fit) of the motor shaft into the drill press chuck
- Drill out the center of the epoxy
Provided nothing was disturbed after step 5, the new hole should be fairly concentric with the original hole; it won't likely be perfect, but it won't wobble all over the place, either.
Then again, if a bushing can be found that works (and is inexpensive enough), then it would probably be easier to use...
