Remove Large gear from shaft - damaged key

[eKretz]

Take a piece of something that's a couple inches thick, flat or round, and turn a short hub that is a tap in fit to the gear bore. Drill a small thru hole in the same setup. Then turn around and put a center using the small drilled hole as a locator.

I was going to say the same if he really wants to check it out, but I'd just do it in one chucking and back turn the diameter to fit in the bore so it's all done in one. Turn it around only to face off what the jaws were touching and add a chamfer/lead-in.

 

[eKretz]

That looks like a taper that fits on the main shaft, i think just make a new insert the gear should be okay, if anything i would worry about the shaft it goes on.

Gear ID won't be okay with that displaced key. I'll be surprised if it's running very true as it sits, but might get lucky, I guess.

 

[Garwood]

I can clean up the bearing surface on the "shaft". And clean up the gear.
I can, I think, set it up in my lathe to see if the gear is running true to the shaft.
I have not seen the main shaft that this sits on, so I don't know the fit, or how it's secured to the main shaft.

Why would you or anyone else care if the gear runs true or not mounted on that messed up hollow shaft with a blown out key?

I would do some checks on that gear once I had it off of there, but I'm lost as to why you think you need to measure it like it is.

If the gear was damaged, bent, whatever, I'd skim the ID and oversize the new hollow shaft to suit.

I guess I look at these pictures and questions and I can't help by ask why the fuck did they take it apart? If they don't care enough to take it to someone that knows something then why bother? Just run the motherfucker. Fixing it wrong's worse than just running it with a trashed key.

 

[eKretz]

Why would you or anyone else care if the gear runs true or not mounted on that messed up hollow shaft with a blown out key?

I would do some checks on that gear once I had it off of there, but I'm lost as to why you think you need to measure it like it is.

If the gear was damaged, bent, whatever, I'd skim the ID and oversize the new hollow shaft to suit.

I guess I look at these pictures and questions and I can't help by ask why the fuck did they take it apart? If they don't care enough to take it to someone that knows something then why bother? Just run the motherfucker. Fixing it wrong's worse than just running it with a trashed key.

I agree with the sentiment here, this actually seems like it would be a lot of running around in circles. Tearing off the Band-Aid and fixing it right one time is almost always the best approach, IMO. Really should have checked for runout while it was all still assembled and operational if you don't have the machine capacity to easily do it.

 

[Overland]

It seems the grinder, gearbox and motor was bought used from an auction.
The new owner installed it all on concrete footings etc, and tried to start it up, only to find it was locked up. The motor wouldn't turn and it was thought the gearbox was the problem.
I don't know who stripped it down. It seems someone then realized the grinder rotor was locked up.
That's all I know, and as they say, it is what it is.

 

[Garwood]

I agree with the sentiment here, this actually seems like it would be a lot of running around in circles. Tearing off the Band-Aid and fixing it right one time is almost always the best approach, IMO. Really should have checked for runout while it was all still assembled and operational if you don't have the machine capacity to easily do it.

Exactly. Making a plug or mandrel or whatever is required to set that bent assembly up to see that, yep, it's bent, just wastes the customers money. $200-$300 just to see it runs out.

Make a print off old part.

Order material.

Cut old part out.

Clean and check gear.

Machine new part

Assemble.

Done.

 

[Garwood]

It seems the grinder, gearbox and motor was bought used from an auction.
The new owner installed it all on concrete footings etc, and tried to start it up, only to find it was locked up. The motor wouldn't turn and it was thought the gearbox was the problem.
I don't know who stripped it down. It seems someone then realized the grinder rotor was locked up.
That's all I know, and as they say, it is what it is.

This makes sense now the whole story is explained.

So if the rotor spins why isn't the gearbox that is not the problem assembled and run?

 

[eKretz]

Yes, always best to get all the info up front... Can't expect solid advice without all the relevant info. This also explains why the gear looks like it was left out in the weather for who knows how long.

 

[Peter S]

Bonfig would supply a new hollow output shaft if required.

Apart from the rust... check that gear first - clean around the gear where it fits onto the shaft - there is something odd going on there (see photo). Maybe a previous repair?



If the gear cleans up ok and isn't damaged in the area I have circled, I would get it pressed off the shaft, then cut a new keyway in the OD of the shaft and reassemble. The keyway in the gear might be OK.

The gear looks like it is simply pressed up against a shoulder. The shaft would have a parallel ID and OD.

Having said that - I would be checking the rest of the gearbox, e.g. the pinion gear, input shaft etc for damage. It might be better to find another unit.

 

[mark costello]

Running when last stopped.

 

[john.k]

Back in the day ,no one had anything,and to remove the sprocket drive from the hub on the old International TD 24 dozer ,they would lay the sprocket hub and sprocket on the ground ,put a track roller shell inside it ,and then use a piece of gelignite the size of you thumb ...........ka-boom ,and the parts would be separated without damage.

 

[Overland]

Bonfig would supply a new hollow output shaft if required.

Apart from the rust... check that gear first - clean around the gear where it fits onto the shaft - there is something odd going on there (see photo). Maybe a previous repair?

View attachment 439036

If the gear cleans up ok and isn't damaged in the area I have circled, I would get it pressed off the shaft, then cut a new keyway in the OD of the shaft and reassemble. The keyway in the gear might be OK.

The gear looks like it is simply pressed up against a shoulder. The shaft would have a parallel ID and OD.

Having said that - I would be checking the rest of the gearbox, e.g. the pinion gear, input shaft etc for damage. It might be better to find another unit.

View attachment 439043 View attachment 439044 View attachment 439042

Peter,
Thanks for your constructive comments and drawings !!
I believe the damage you have identified may well have been from when the bearings were torched off.
Bob

 

[Overland]

Back in the day ,no one had anything,and to remove the sprocket drive from the hub on the old International TD 24 dozer ,they would lay the sprocket hub and sprocket on the ground ,put a track roller shell inside it ,and then use a piece of gelignite the size of you thumb ...........ka-boom ,and the parts would be separated without damage.

I was wondering how big a press would be needed.

 

[4GSR]

Running when last stopped.

More like running up to when it was wrecked!

That's why it wound up on the auction block. Somebody's junk became someone elses nightmare!

 

[just Dave]

Who is working on the seized rotor. If you are only doing part of the job or if you are instructed to make minimal repairs to get it going, then the approach to the customer should not include warranty

 

[memphisjed]

Now that it’s apart to this point removing old sleeve would be to bad. Pecking it away in the mill would be safest. Slow and mindless is sometimes the fastest.

 

[mark costello]

More like running up to when it was wrecked!

That's why it wound up on the auction block. Somebody's junk became someone elses nightmare!

With My luck, I don't see how it did not end up in My yard to make for a sleepless night or two.

 

[4GSR]

With My luck, I don't see how it did not end up in My yard to make for a sleepless night or two.

Believe me, If dad was alive, he would have drug it home from one of his buddies to repair for them. I have a Index mill he did a repair in trade for the mill. Oh, I would be the one doing the repair, too!

 

[Overland]

I set the gear and shaft up in my lathe to take some measurements.
I adjusted the chuck to get that end true, on the bearing surface, and made a plug for the tailstock end, cleaned up the shaft and took some measurements, as shown in the diagram attached.
The chuck end is showing pretty significant ovality in the shaft.
The gear is not running true either, when measured at the top of the tooth.
So clearly a new shaft is required.
Hopefully the bore of the gear is not damaged/distorted.
I've reached out to Bonfiglioli to see if a new shaft is available, the price and delivery.
The shaft is about 12" long, with max OD about 7.50" and a bore about 4.75".
Bob
ps anybody have any idea what size press would be need to get the shaft out of the gear ? (the other option is to cut it out of course).

 

[Bill D]

Even if you cut the old shaft out you will need a very big press to install the new one.
Bill D