Removing A Flywheel

Part of Metal Type’s Printing Advice section, here Phil gives advice on removing a press flywheel.

Removing a flywheel, employing a wheel or gear puller is sometimes a necessity.

My comments are:  be real careful here, this can be super tricky.  Do not even attempt this unless you are really mechanically inclined and experienced.

I would advise trying most any other method of moving a press other than attempting to remove a flywheel.

Some manufacturers fitted a flywheel so tightly that it had to be heated to get it on the shaft and then used a square pin in a channel called a keyway, to ensure that the wheel did not shake or vibrate off.

And getting such a wheel off sometimes requires dry ice wrapped around the shaft, for 12 hours and then the hub of the wheel has to be heated with  two or more blow torches, to facilitate the removal.

And be really  careful to heat only the hub and heat it as fast as you can so as not to leach away the cold from the now hopefully shrunken shaft. This is the reason for using more than one blow torch for heating the hub.

And the reason for the dry ice being on the shaft for 12 hours is to be sure that the shaft is as cold as the dry ice and that there is enough  “cold sink,’’ in the shaft so as to last as long as possible, and that there not be too much cold loss in the shaft till the hub is heated enough for the wheel to be removed.

Also the square pin in the keyway, can be a bear-cat to remove. I have had to drill out several of these pins. And they all seem to be machined from the hardest steel that was ever made. This is really hard to do and can take hours and many more than one drill bit.

Carbide Drill Bit

I always use carbide drill bits for this sort of job and once had to switch to a diamond drill bit. These speciality bits are all so expensive.

I personally would prefer to remove part of a wall and remove the press, rather than try to remove the flywheel.

I have seen this kind of job proceed without any trouble at all, Just remove the square pin, if there even is one, and then manually pull the flywheel off. Nothing to  it at all. Just as easy as you please.

On the other hand, I have seen this job take two days and one journeyman machinist  and two highly qualified helpers.  And  over ten high quality drill bits to remove the square pin.

Lastly;  good luck to you. The wheel may come off easy peasy. Or you may find otherwise. Again, good luck and please do let us know how it went.