930B 6’ finish mower

[Danica]

Hi, I just bought this used mower (I have another for parts) and noticed that a good chunk of this pulley broke off. So question is:

The question is hopefully pretty simple. Will this pulley spin off the threaded bolt under parts 2 and 3 ( see illustration) or do I have to remove the entire spindle in order to put a new pulley from other 930B I keep for parts on?

I hope these pics make things clear. I have gear pullers but am hesitant to use since I think the pulley is screwed on give it is on a threaded ‘post’ coming up from below.

Thank you in advance for any advice.

 

[zzvyb6]

Block the blade from underneath with a piece of wood/log so it can't turn. Then tap it with a hammer at the spokes counter-clockwise to see if it loosens as it would if threaded. But, it looks like there is a keyway peeking out (part no. 9), (as I would expect) since a threaded pulley is almost unheard of. Then a pry bar or a wheel puller should lift it off. Since you have a spare mower with the same parts AND the pulley is cast, I'd hit it with a cold chisel and crack it off.

 

[oldnslo]

Drawing shows tapered shaft with wood ruff key. Pulley might come off if you can get puller jaws in the slots. I would suggest threading the nut back on part way since with tapered shaft they can suddenly break loose and jump up at you with surprising force. Heat may help break it loose with puller tension.

 

[Danica]

Thanks so much. Has been sitting with penetrating oil 4 days. My only question relates to the “key way” (part 9). Is it spring loaded (probably not?) so it is there to prevent the pulley from unscrewing. But how on earth do you get it outta there?

Do I have to take off whole spindle? (sounds like no).

Also thanks to reader who said to keep the retaining nut on top lest it pop out with amazing force using pullers. I had not even considered that.

Hope that made sense, yes I have a spare 930B to get the new pulley but I’m going to have to complete the same exercise with it I assume.

Will heat it up first too with torch to get maybe an extra .01” space.
Thank you again.

 

[oldnslo]

Danica,
The key is to keep the pulley from spinning on the shaft. With tapered shaft part of the load torque is absorbed by the taper fit, key absorbs the rest. The key is not spring loaded in fact you typically have to drive them out with a punch. Since that appears to be cast pulley heat the center as evenly as you can since with taper if it moves at all it is typically free to move the rest of the way.

NOTE: Pay attention to how the key is installed in the slot in the shaft. They may sit vertical with center line of the shaft or parallel with the taper. If oriented wrong the new pulley may not tighten down properly.

If all else fails get a BIGGER hammer and the problem will become obvious and probably worse ;-)

 

[Danica]

Danica,
The key is to keep the pulley from spinning on the shaft. With tapered shaft part of the load torque is absorbed by the taper fit, key absorbs the rest. The key is not spring loaded in fact you typically have to drive them out with a punch. Since that appears to be cast pulley heat the center as evenly as you can since with taper if it moves at all it is typically free to move the rest of the way.

NOTE: Pay attention to how the key is installed in the slot in the shaft. They may sit vertical with center line of the shaft or parallel with the taper. If oriented wrong the new pulley may not tighten down properly.

If all else fails get a BIGGER hammer and the problem will become obvious and probably worse ;-)

Thanks a ton. Is the key accessible without taking the whole spindle off?

 

[oldnslo]

The key will be exposed when you pull the pulley off.

The only difference between tapered keyed shaft and straight key like electric motor is the taper is held in place with that nut and taper also helps transmit torque. Straight key the key transmits all the torque.

Another option is IF repeat IF the spare spindle assembly is good just replace the whole assembly. Looks like four bolts hold the whole assembly in place.

 

[Danica]

The key will be exposed when you pull the pulley off.

The only difference between tapered keyed shaft and straight key like electric motor is the taper is held in place with that nut and taper also helps transmit torque. Straight key the key transmits all the torque.

Another option is IF repeat IF the spare spindle assembly is good just replace the whole assembly. Looks like four bolts hold the whole assembly in place.

Yes you’re absolutely right!