Pulling a pulley

[AdeV73]

Now I've got a bench sorted (had to build the damn thing), I've started in on my startomatic alternator - and boy, has this thing been abused

Starting with this:           I've managed to pop the top box off to end up with this:

(as always, click the pic for the big versions)

As you can see from these pics, the brushes end has taken a good thump at some point:




Anyway... this afternoon's showstopper is the pully:



I'm assuming it's held in with a gib key, but someone's previous efforts at removing said key have resulted in the head being ripped off, right at the pulley face. So, I'm further assuming that my next task is to get in there with a drill & start drilling the key out bit by bit? Any hints (especially ones which will save me hours of drilling) much appreciated.

[mobile_bob]

this is what i would do if it were me

find a grade 8 , 3/4 inch bolt and have someone that can do it well
mig weld it onto the end of the shaft

then slip a 3/4 drive socket over the bolt, socket large enough to provide clearance
inside for the shaft and key to clear.

then put a grade 8 washer over the threads, install a nut and start cranking on it.

what will happen is the pulley be effectively pushed back off the shaft enough
to loosen the key.

after which just cut the bolt off and clean up the end with an angle grinder.

i have used this method to pull all sorts of stuff, including gib keys

btw, the welding will not hurt the shaft.

bob g

[compig]

I think religion is the answer !!

[AdeV73]

Jens,

I don't really do praying.... but I'll make an exception in this case

However, the shaft can be sacrificed because it's as bent as a nine bob note:



(photos show gap varies between 15/16ths and 1"3/16ths...)


Meanwhile, I've done a spot of wire-brushing and WD40 applicating (I may switch to diesel or vinegar, rather than WD40), and now it looks a bit nicer:




Bob: That's an interesting post; the chaps next door are sh*t hot MIG welders, so I'll ask them to add a bolt. But I'm not 100% sure I get what you're suggesting... could you quickly draw & scan an image of what you mean, as I suspect it'll be easier than trying to describe it so as my worn-out brain comprehends... Also, as I said above, I don't much care for the shaft, it's bent to buggery anyway. I don't want to saw the end off, if I can help it, because I'd like the length of the shaft for making a new one. But if I have to chop it off, so be it.



PS: Anyone got any idea what the screw hole in the nose of the pulley is for? I have a flywheel which bolts to the outside of the pulley via the three main boltholes you can see, but the central one's got me stumped...

[compig]

I see what he means. Basically that arrangement would push the pulley towards the gen and so , hopefully , loosen the key enough to pull it.

[AdeV73]

I see what he means. Basically that arrangement would push the pulley towards the gen and so , hopefully , loosen the key enough to pull it.

Bing, penny drops - I see what he means as well, now.

I'll see about getting that nut welded on tomorrow 

Thanks BTW - that last bit of explanation just tripped my feeble brain into enough life to see it

[compig]

I'll see about getting that nut welded on tomorrow 

You mean bolt , with the head end welded to the shaft. How many beers you had today ??!! LOL !!

[AdeV73]

I'll see about getting that nut welded on tomorrow 

You mean bolt , with the head end welded to the shaft. How many beers you had today ??!! LOL !!

Gah! Of course I do...

No beers today, but several on both Friday & Saturday, so maybe I'm still suffering the after-effects.... And it was jolly toasty today, so I'm probably dehydrated too. Honest! 

[AdeV73]

The hole on the side of the hub is for a set screw for the key.

Thanks - that's what I was wondering (I'd wondered about the centre hole as well, but guessed it was from the original machining).

WRT your additional thoughts: I concur... but I'll have a stab at getting the pully off the proper way first. I'm not sure if I can completely remove the shaft from the housing without first removing the pulley, however; I'm fairly sure that the front casting comes off over the shaft, similarly the rear casting, allowing you to withdraw the windings from the central body. But, if I can pull the rear & centre portions out, maybe I can remove the windings, allowing the rest of the shaft to be pulled through the front bearing. Assuming it's not tapered in any way, I could presumably then pull the pully back along the entire shaft & off the back end... If not, then after measuring i can simply cut the bent end off & go about removing just that bit. The pulley needs to be saved, ideally.

Although the shaft is to be sacrificed, it'd be nice to keep it in as few pieces as possible until I've had a chance to measure any machining it's had done to it...

[M61hops]

Hi Ade, looks like you've got a real challange here.  I think you will find a allen head setscrew down at the bottom of the threaded hole in the pulley hub; that is what was intended to hold the pulley to the shaft.  If you crank on the setscrew good and hard it pushes the key tightly aginst the bottom of the keyway and makes a dent into the top of the key which also smushes the top edges of the key into tight contact with the keyway of the pulley.  These forces are what holds the pulley on the shaft.  Normally if yoy remove the setscrew and put a beefy puller on the pulley you can pull the pulley off and the key will come off still stuck in the pulley.  You could read the thread on electrolyses rust removeal on this forum and follow the directions to de-rust the pulley and shaft and then try a beefy puller that uses the three threaded holes in the pulley to pull the pulley off the shaft.  You might also have to heat the pulley, and for sure file the mushroomed end of the shaft down.  It would probably be faster to cut the shaft off and bore the remains out of the pulley if you are not going to try to straighten the shaft to save it.  If it was mine I'd try to save the shaft  !

[AdeV73]

If it was mine I'd try to save the shaft  !

I know what you're saying, but it really is knackered - front back & middle are all bent out of shape to some extent. Besides, I'm not even sure how you'd go about straightening the shaft, especially down to the sort of tolerance it's going to need, without needing to machine it afterwards. And if I have to machine it, I'll either have to add a thin "bearing" for the pulley to sit on, or make a new pulley: So ultimately, the shaft is toast...

[GuyFawkes]

ignore this at your peril.

pulleys are cheap and easy to make, shafts are not.

bent / damaged shafts are easy to repair

cut the pulley off, save the pieces.

disassemble the head

repair the shaft as required, then do what is required as far as bearings / bushings replacement pulley

this is a piss easy but time consuming job to get RIGHT, and piss easy to get wrong and make a mountain out of a molehill by trying to save a fucked pulley on a riveted shaft end.

engineering principle, until you extract the bare shaft, you cannot measure it for deflection, damage and wear.

engineering principle, until you can measure something, you are throwing sticks in the dark.

engineering principle, to get from throwing sticks in the dark to knowledge, perform as few irreversible actions as possible, and any you do do, make them cheap and easy to replace with new.

HTH

[listeroidsusa1]

I would save both the shaft AND the pulley. Simply drill a ring of holes around the shaft and get the pulley separated from the small hub on the shaft that will be left intact. Once the pulley proper is off it will be a simple matter to take a hacksaw and split the small portion of the hub and remove it from the shaft. Once the shaft is bare it can be better assessed. If necessary, the shaft can be turned to a smaller size and a new keyway cut. As far as the pulley itself is concerned, it is also a simple lathe job to cut a 3/4" per foot taper into the pulley and use a common taper bushing. The bushings will be available in any size that the shaft cleans up to. A standard SK bushing fits into a 2.75" hole with the 3/4" per foot taper. Other series taper bushings would work as well too.

My .02 worth,
Mike

[AdeV73]

The slip rings at the back end look like they'll be just as troublesome as the pulley 



On the bright side, The tail of the shaft looks to be straight, so I should be able to fabricate a puller to extract the rings. Meanwhile, it's getting a good soaking in WD40...

[AdeV73]

Cool - the slip rings came off after just 2 days in WD40 & a bit of gentle crow-bar (pry-bar) persuasion

Starting to get somewhere now...