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Large pulley bore repair

KBS

Plastic
Joined
Jul 19, 2019
Location
Orkney
A agricultural customer has asked me to sort his stone crusher, the drive pulley and flywheel have gone slack on the shaft and damaged the key ways in them. They are 1m in dia and 120mm bore, 32mm key. They are to big to go in my lathe so I was thinking to weld up the bores and machine them out with the boring head on the milling machine, I’ve not broached a key way that size before though. The other option my old boss mentioned to me was to bore them out and fit taperlocks with parallel sleeves. Has anyone used those before or got any advice on a job like this?

Cheers
 
It's a lathe job. You will have to battle every detail to do it on the mill, and it will be hard on the mill, going over those interruptions, whether you bore out the old hub or weld it (with correct welding rods, probably for cast iron, use spark test to determine). You'll be bending over and jumping through hoops at the same time :) And without a shaper to cut the key, what are you going to do?

Also, almost certainly, the shaft journals are worn some, so those need to be fixed. Don't let anyone tell you that they still look good as is. These fits have to be good to last.
 
IME the forces and shocks on stone crushers are brutal and go right back up the power train etc etc

So, ........and please no offence intended, unless you really know what you're doing (and it sounds like you're unsure) I would steer well clear, ......because unless everything else is dead nuts on right, ....you are only making a rod for your own back.

P.S. That's why old stone crushers are cheap, because the spares prices are :eek: ........folks buy them and want cheap repairs, which IME are almost never successful.


Of course YMMV.

Hu Flung was quicker on the draw.
 
You are out gunned, better pass the job onto a shop with the right equipment. This was my type of work for 50 years, if it is a straight bore the key(s) are tapered, if it is a tapered bore the key(s) are straight. The fit is everything. The labor involved to tear down and build up is more than the machine shop charge, it can not fail...Phil
 
A agricultural customer has asked me to sort his stone crusher, the drive pulley and flywheel have gone slack on the shaft and damaged the key ways in them. They are 1m in dia and 120mm bore, 32mm key. They are to big to go in my lathe so I was thinking to weld up the bores and machine them out with the boring head on the milling machine, I’ve not broached a key way that size before though. The other option my old boss mentioned to me was to bore them out and fit taperlocks with parallel sleeves. Has anyone used those before or got any advice on a job like this?

Cheers

If you want to email me I can help you with a plan to do this type of job. I do this type of work daily.
Depending on the type of equipment and tooling you have available will decide how to approach it.
[email protected]
I have done some on a bullard, some on a horizontal boring mill, some with portable boring equipment.
How you approach the job will depend on how bad the hub is, how bad the shaft is etc.
 
Cheers for the input guys, I’ve not committed to the job just told him to take parts past and I would have a look at them, it’s small Agricultural crusher that tows behind a tractor he’s had the machine from new and it’s been back at the supplier once before because of bearing problems on the main shaft and he said it was worse when I came back from them! tbh the machine is to light for the job as there is cracks appearing in the frame that holds the crusher plates.
We are pretty limited to options to pass the job on here as we live on island, so will have to look into finding a company that it could be shipped to.
 
Cheers for the input guys, I’ve not committed to the job just told him to take parts past and I would have a look at them, it’s small Agricultural crusher that tows behind a tractor he’s had the machine from new and it’s been back at the supplier once before because of bearing problems on the main shaft and he said it was worse when I came back from them! tbh the machine is to light for the job as there is cracks appearing in the frame that holds the crusher plates.
We are pretty limited to options to pass the job on here as we live on island, so will have to look into finding a company that it could be shipped to.

He's over-worked it, then. To put "abuse" gently.

Mess with it, you will be "married" to it for the rest its sad life, "unnaturally extended".

Frankencrusher. With progressively gnarlier band-aids layered-on. Then pushed beyond THEIR limits.

Zombified, even..

DAMHIKT!
 
Cheers for the input guys, I’ve not committed to the job just told him to take parts past and I would have a look at them, it’s small Agricultural crusher that tows behind a tractor he’s had the machine from new and it’s been back at the supplier once before because of bearing problems on the main shaft and he said it was worse when I came back from them! tbh the machine is to light for the job as there is cracks appearing in the frame that holds the crusher plates.
We are pretty limited to options to pass the job on here as we live on island, so will have to look into finding a company that it could be shipped to.

That would be my ''plan of attack'' AKA ;- kicking it in to touch ;)

Which island are you on?
 
Up in Orkney, there is one guy up here who might have a lathe big enough to do the job but from what I here he’s not in the best health now and isn’t taking on big jobs so I don’t want to bother him
 
yes i tend to agree with above, its a problem thing....suggest the owner looks into a Jaques unit.

ST48 Jaw Crusher

250 BHP motation thirst, and @ just a tad under 50 tons, avoir?
Could stop him abusing the tractor by towing it about .... as a side benefit?

:)

But... expect it to be abused as well!

"Some folks", as the late Field-First SGT Willie Williams once put it:

"Could find a way to f**k up a steel ball with a rubber hammer."
 
If you want to email me I can help you with a plan to do this type of job. I do this type of work daily.
Depending on the type of equipment and tooling you have available will decide how to approach it.
[email protected]
I have done some on a bullard, some on a horizontal boring mill, some with portable boring equipment.
How you approach the job will depend on how bad the hub is, how bad the shaft is etc.

Why not post it "right here" and help more people ?

It's all about sharing information.
 
Up in Orkney, there is one guy up here who might have a lathe big enough to do the job but from what I here he’s not in the best health now and isn’t taking on big jobs so I don’t want to bother him

Orkney - wow that's very North.

FYI That pulley bore is only a minor part of the problem, the reals work comes with the fitting up and ercting, because unless that's done right, averything else is a waste of time.
 
Orkney - wow that's very North. You don’t get much further ��

FYI That pulley bore is only a minor part of the problem, the reals work comes with the fitting up and ercting, because unless that's done right, averything else is a waste of time.

Yeah he has also asked about if could do the re assemble, size wise doesn’t bother me as I worked offshore on Drilling rigs for years as a mechy/welder(they are too cheap these days to pay for 2 guys) so ive been involved with some pretty big equipment rebuilds. I have the pulleys sitting outside my workshop but waiting for the shaft so I can get a mic and see what state that is in. I would post some pics if I could get photobucket to work
 
I do not recommend weld buildup and remachine inside a cast-iron bore because of differential expansion, cracking and unmachinable hard spots.

I would use some form of tapered bushings. If you can bore the taper in the FW, then you clean up the shaft and make a bushing like a QD to fit the FW to the shaft. If you can only bore the FW straight (as on your milling machine), then make or buy a matched set of bushings to go from the shaft to the bore...you can buy such stuff, too. Ringfeder is the old company, there are cheaper competitors now.
 
If you HAVE to do the job post some pics and I will walk you thru it. By the what you posted the shaft and keys are fine (hard to believe) and you only have to repair the bore and keys in the hub of the cast pully...Phil
 








 
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