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The worm gear is on the axle.  All you need is force - I use a giant drill press, but an arbor press is better.

The worm is the one on the motor shaft.  It is trickier.  You need two pieces of steel, machined to fit between the motor and the worm, and tied together somehow.  I use 2-56 machine screws, but clamps would do if you are careful.

then rest the motor upside down between the jaws of a vise, heat the worm with a propane torch for about ten seconds, and tap the shaft out of the worm with a nail set.  Catch the motor in a giant rag about two inches below where it will fall out of the worm.

putting the new worm on probably requires a drop of 600-series Loctite.  Be very careful about how much force or shock you give that motor shaft.  It will not take much to dislodge internal components or bend the shaft, then it is new motor time.

I have only done MTH and K-Line motors this way - other motors may need different handling.  Older 2-rail has a splined or knurled shaft, eliminating the Loctite step.

bob2 posted:
Be very careful about how much force or shock you give that motor shaft.  It will not take much to dislodge internal components or bend the shaft, then it is new motor time.

That should be in capitol letters!  It's very easy to slide the commutator on the shaft internally and the motor is history!  Don't ask me how I know this.

I'm curious, why not press the worm off the motor shaft?

I made this puller to remove flywheels. To remove motor worms I have a steel plate to bridge the jaws and slot just wide enough for the motor shaft and undercut for the gear. I use three screws, far right is for starting if the shaft protrudes beyond the flywheel or gear, one in the jaws brings the shaft flush, and the middle one drives the shaft though. This minimizes the possibility of bending the shaft.  I think Frank Timko sells a similar tool but last time I checked his website was down.

This puller by the late Boxcar Bill has the gear puller integrated in the jaws. On mine that narrow slotted piece is separate and just fits above the jaws above.

Pete

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