Author Topic: Rotor/armature removal 2 pole tapered shaft engine.  (Read 9847 times)

carlb23

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Rotor/armature removal 2 pole tapered shaft engine.
« on: November 17, 2015, 09:25:02 PM »
I have a two pole 6.8kw genhead on an 12hp tapered shaft engine with a broken conrod.  I have removed the rotor / armatures from tapered shaft engines before without any real difficulty, but this one is being real stubborn.  Normally I would remove the center bolt on the rotor and insert a long rod then thread a bolt into the threaded end of the rotor and just push the rotor off the engine crankshaft.   This one is not budging and pulled the threads out of the end of the rotor.  I then tried (I never tried this method before) to whack it on the laminations with a 3lb dead blow hammer with no success. 

Any ideas how to get this stubborn rotor off the tapered engine shaft? 

Thanks

Carl

vdubnut62

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Re: Rotor/armature removal 2 pole tapered shaft engine.
« Reply #1 on: November 18, 2015, 08:12:32 PM »
Gunpowder.

NO! Just kidding. But I have been sorely tempted.
 Fill the hollow rotor with grease, then with a close fitting rod and a big effing hammer proceed to drive the two apart.
You will have to be creative as to how to fill the rotor with grease, you will have to start at the bottom of the hole, of course, and watch out for air bubbles, they will cushion the blows from the hammer. A steel line of the appropriate size and a drive in grease fitting works pretty good to fill from a grease gun, or you can  adapt with various fittings and unions.
I wish you luck!
Ron.
« Last Edit: November 18, 2015, 08:14:13 PM by vdubnut62 »
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carlb23

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Re: Rotor/armature removal 2 pole tapered shaft engine.
« Reply #2 on: November 18, 2015, 08:55:19 PM »
blue dot, red dot or 4350 ;D

This thing is really stuck. One of the problems is that i inserted a rod into the center and tried to use a bolt threaded into the end of the rotor to free it but it pulled the threads out of the rotor.  The rod must have bent as well as it will not come at either.  I will re-tap the hole to 1/2 x 13 and try again.  If not i just may try some 4350 ;D

Thanks

Carl

vdubnut62

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Re: Rotor/armature removal 2 pole tapered shaft engine.
« Reply #3 on: November 19, 2015, 02:20:03 AM »
In case some well meaning individual applied Loctite in a previous encounter, can you get some heat on it without causing more damage?
Ron.
"The penalty good men pay for indifference to public affairs is to be ruled by evil men."   Plato.

"Remember, every time a child is responsibly introduced to the best tools for the protection of freedoms, a liberal weeps for the safety of a criminal." Anonymous

carlb23

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Re: Rotor/armature removal 2 pole tapered shaft engine.
« Reply #4 on: November 19, 2015, 10:21:47 AM »
I may be able to get some heat on it but it's kind of hard with the bell housing in the way.   

vdubnut62

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Re: Rotor/armature removal 2 pole tapered shaft engine.
« Reply #5 on: November 19, 2015, 03:39:19 PM »
Fine threads are stronger than coarse. Just sayin.
 Could you get one of those Chinese finger trap looking J-cord hangers on the end of the bent rod after you drill out the rotor?
 Maybe if you could get the bent push rod out and get a new straight one in.................?
Ron.
"The penalty good men pay for indifference to public affairs is to be ruled by evil men."   Plato.

"Remember, every time a child is responsibly introduced to the best tools for the protection of freedoms, a liberal weeps for the safety of a criminal." Anonymous

carlb23

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Re: Rotor/armature removal 2 pole tapered shaft engine.
« Reply #6 on: November 19, 2015, 05:29:22 PM »
I drilled and tapped the bent rod and tried to pull it out but no go.    I only have a 1/2 x 13 tap so i guess i will pop down to the hardware store and pickup up a 1/2-20 tap and grade 8 bolt.

Thanks

Carl

LowGear

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Re: Rotor/armature removal 2 pole tapered shaft engine.
« Reply #7 on: November 19, 2015, 06:07:03 PM »
Hi Carl,

You know I'm a fan but you're batting 0-2 on this threaded rod program.  I don't like heat but sometimes a guy has to do what a guy has to do.  I was cleaning an apartment where some substance abusers were living (using the word very loosely) and ran into a megaton butane cigarette lighter that fits into the tightest of spots.

I don't suppose there's a manual that announces "After loosening the fourth nut on the intake manifold the rotor should pop off with a slight counter-clockwise twisting motion."

Casey
NPR Tipper/Dump Truck
Kubota BX 2230
Witte BD Generator
SunnyBoy 6000 + SolarWorld 245

Thob

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Re: Rotor/armature removal 2 pole tapered shaft engine.
« Reply #8 on: November 24, 2015, 02:20:25 AM »
I'll disagree with the "fine threads are stronger" statement.

It's true that fine thread bolts are stronger than coarse thread bolts (all else being the same).  This is because the fine threads leave a large minor diameter in the bolt, which leaves more material for stress ON THE BOLT.

But when comes to stripping the threads, coarse threads are stronger.  This is because the tolerance between the male and female threads uses up more of the "meat" of the thread on fine thread as compared to the coarse threads.

The best solution to prevent stripping the threads is to provide as long of thread engagement as you possibly can.  If you have a welder, consider welding a nut on the end of the shaft - or better yet use one of those coupling nuts intended for all-thread (the ones that are about 1" long).

It's also true that fine threads will provide more "clamping force" than coarse threads for a given amount of torque, but this isn't the problem here.

Older Lincoln AC-225 welders (and others I'm sure) have a setting for thawing frozen pipes (I think it's at 70 amps).  You put the ground on one end of the pipe and the electrode holder on the other end - causing current to flow through the pipe (only works on metal pipes).  If you have this type of welder, you could use that to flow current through the crank shaft and generator shaft and get some heat on it that way.  Turn the welder off before torquing the bolt to separate the two to prevent it from arcing if it does separate.

It may also be time to decide to save one part and not the other - either the engine or the generator (having beat on the laminations, you may have already decided...).  Start cutting away pieces of the one you don't save.
Witte 98RC Gas burner - Kubota D600 w/ST7.5KW head.
I'm not afraid to take anything apart.
I am sometimes afraid I'm not going to get it back together.

carlb23

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Re: Rotor/armature removal 2 pole tapered shaft engine.
« Reply #9 on: November 24, 2015, 10:18:02 AM »
My Sciatica has been acting up the last week or so, so I am not even looking at this problem at the moment.   I will get back to it when i am feeling better.  I don't have an old stick welder only a mig.   

Thanks for the advice guys.

Carl

quinnbrian

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Re: Rotor/armature removal 2 pole tapered shaft engine.
« Reply #10 on: December 27, 2015, 02:15:12 AM »
I have an old Coleman genset with a good head...motor is NFG, I think its a 5500/6500 watts head if you need one let me know. I was going through a lot of generator until I put my Lister into service.
Cheers
Brian

carlb23

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Re: Rotor/armature removal 2 pole tapered shaft engine.
« Reply #11 on: December 27, 2015, 12:05:55 PM »
Thanks for the offer and i will be in touch if i can't get the original off.   I have not looked at this in over a month as i am still dealing with my back issue and while i am about 80% better this is a real pain in the butt that takes a long time to get better and I don't want to re-injure myself by overworking my back too soon. 

Thanks
Carl

quinnbrian

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Re: Rotor/armature removal 2 pole tapered shaft engine.
« Reply #12 on: December 27, 2015, 09:19:09 PM »
Yup back pain is not easy to deal with... they told me , back in 1993, that I'd never work again ( car accident) but it took me 3 years there after, to get back on my feet!!  Take your time, with out your back...life is hard with out it!
Cheers
Brian