Author Topic: 4 stage pulley  (Read 544 times)

Offline Maca

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4 stage pulley
« on: August 27, 2019, 07:17:44 PM »
I'm currently trying to get a lathe back up and running which required me to buy a new motor.  The standard 1hp single phase motor comes with a 19mm drive shaft.  Unfortunately the old motor and pulley have a smaller shaft diameter (about 16 or 17mm I think, or possibly an imperial equivalent). 

The small diameter is 85mm outer diameter and the large one is about 195mm.  For the life of me I can't find a 4 stage pulley online with these kind of dimensions.  Any ideas where I can get one? 

I also read about someone who tried to drill the bore out and because of the keyway it knocks the drill off and you end up with an oval bore unless you go to a professional workshop where they can anchor the piece and drill accurately.  You then need to machine out the keyway which is very difficult.  So I'd rather not go down that route if possible.

Offline Sandy

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Re: 4 stage pulley
« Reply #1 on: August 27, 2019, 09:52:33 PM »
You don't say what the issue is with the original motor; would you be able to have the original motor rewound or repaired or is there potential to make use of a taper-lock bush to fit your pulley on a new metric motor drive shaft?

Not certain I've understood your problem so apologies if I have and the above doesn't make any sense.

Offline Twisted Trees

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Re: 4 stage pulley
« Reply #2 on: August 27, 2019, 10:34:24 PM »
Personally I would be looking for an engineering shop that can bore and re-key the original pulleys. It will probably not cost too much, as you say it is a boring job for a big machine, not a hand drill and a file.

Offline Derek

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Re: 4 stage pulley
« Reply #3 on: August 27, 2019, 10:41:22 PM »
Find a local model engineering club maybe one of the members can do it for you with a lathe and a broach for the keyway. The keyway can also be cut on a lathe but is very time consuming

Offline Duncan A

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Re: 4 stage pulley
« Reply #4 on: August 28, 2019, 09:42:44 AM »
Obviously depends on how much you are willing to spend and whether it's worth investing much in the lathe but one option is to fit a single pulley to the motor (probably easiest with a Taperlock coupling) and use an inverter for speed control. You then have a much improved lathe!
Duncan

Offline The Bowler Hatted Turner

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Re: 4 stage pulley
« Reply #5 on: August 28, 2019, 10:18:29 AM »
This is a boot and braces fix.As the pulley is made from Aluminium you should be able to mount it on a lathe and turn it to diameter yourself.The keyway poses a problem but if you remove the keyway insert from the shaft you can then drill the pulley to take a couple of grubscrews which will then fit into the keyway giving you the same result. If I remember correctly a 1/4" bolt is a ton shear so 2 should be more than adequate.

Offline Maca

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Re: 4 stage pulley
« Reply #6 on: August 28, 2019, 01:36:56 PM »
Thanks for the replies everyone.  The original motor burned out the run capacitor and when I replaced it it did the same with the new one within a short time.  It was overheating quickly too. 

So far I haven't had much luck sourcing a new pulley.  I have enquired about a pulley for a Graduate lathe, waiting to hear back on that but I'm also going to drop the pulley and motor off at a local machine shop tomorrow.  They're going to have a look and see what they can do.  Hopefully one of those options will materialise because the only other thing I can think of doing would be to put in variable speed so I could run it off a single stage pulley. At this moment in time I could not justify the expense of that so I would probably have to park this lathe up.

Offline Twisted Trees

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Re: 4 stage pulley
« Reply #7 on: August 28, 2019, 02:25:14 PM »
I am sure the machine shop can help, small engineering shops bread and butter is converting imperial castings to metric motors.

Offline The Bowler Hatted Turner

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Re: 4 stage pulley
« Reply #8 on: August 28, 2019, 04:35:11 PM »
The other thing is source some good quality plywood and make one from that.

Offline Maca

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Re: 4 stage pulley
« Reply #9 on: August 29, 2019, 08:34:29 AM »
Never thought of making one out of wood, in my head I'm thinking the keyway wouldn't last but it's not an option as the lathe is currently out of action anyway. 

The foreman at the machine shop said it shouldn't be a problem for them to do it, the keyway is a bit of a....insert expletive of your choice here...but otherwise shouldn't be a problem.  So hopefully I'll get that back next week and be up and running.

Offline Maca

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Re: 4 stage pulley
« Reply #10 on: September 16, 2019, 06:57:34 PM »
So it took a couple of weeks but the local machine shop messaged to say they had done the work and there was no charge for it. Picked it up this afternoon and left a case of beer in the workshop. Happy days.

Offline Twisted Trees

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Re: 4 stage pulley
« Reply #11 on: September 16, 2019, 10:49:48 PM »
Stunning result, great when engineers help out other engineers.

Offline bodrighywood

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Re: 4 stage pulley
« Reply #12 on: September 17, 2019, 08:11:01 AM »
Similar story: Got a pillar drill froma friend, heavy duty Waco but it kept blowing trips every time it was switched on. OK once it had been running though. Called electrician who does my pat testing for me. Spent an  hour going over it and found no electric faults but said it was probably dust as pillar drill had been lying round unused for several years before I got it. When asked cost told none as he had been passing anyway. Stripped and gave good clean inside no problems since

Pete
Turners don't make mistakes, they have design opportunities