55lb Indian hammer for GIB key?

[jfuerst]

On new years eve i mentioned to my extended family that I was looking at getting a backup generator... Everyone laughed at my paranoia... Next day the power was out for 12 hours.... No one laughed.

SO after reading the internet (yup all of it) I managed to round up a new "kit" 8/1 engine. As we all know 50% of the reason for this was the need for a generator, and the other 110% of this was driven by hobby and an addiction to tinkering with things that are just fine if you leave them alone...

Needless to say I proceeded to dismantle the kit with the intent of a full rebuild without sand that will run forever on a 55 gallon drum of diesel. After about 6 hours of utter defeat with all kinds of creative ways to pull a GIB key I constructed a flat 1/4" plate GIB key puller from metal I had laying around the house (hole in the middle with 3 bolts like I see advertised everywhere)...it bend like butter... So not to admit defeat I cut one out of some 9/16" plate. The first side pulled off with lots of lube and some big wrenches. Feeling victorious over machine I diligently went to work on the second side and immediately snapped the head right off the key...

I have to admit here that I am absolutely dumbfounded that these keys being brand new (no rust) and after a week of JP grease spray (to "loosen" them up) that this is possible. Do these keys really need to be in so tight? Do the Indians all tote around 55lb hammers?

I went ahead and pulled the crank out still connected and have finished stripping down all the parts and freeing the dixie cup worth of sand from the case, but now I need to deal with the situation at hand before putting it all back together.

I have tried welding on a new head, which peals right off the key, I welded on a slide hammer and hammered till my hands were red.

What advice do you have for me? Put it back together this way? drill it out? what? Seems dangerous to put it back together without a head on the key, but with the size hammers they make over in India I may be just a safe as I was before...

Ideas anyone?

[CD in BC]

Liquid nitrogen on the key would be my suggestion.  Preferably not where the slide hammer is welded on though, or it will probably crack off.  Another more radical option would be drilling from the end of the crank until you can get a drift pin onto the end of the key, but no guarantee that would work and you might just bugger up the crank permanently without achieving anything.

On the bright side, if the key was driven in that hard it is putting an abnormal and possibly even dangerous load on the hub of the flywheel, which might make it prone to failure at some point if left that way.

Since you're the thorough type you might want media blast and magnaflux the hub(s) when you get this wheel off, just to make sure no cracks have been started in the area of the keyway by this over-stressing.

[dieselgman]

I have not pulled one of these before, but many other such situations have been solved with heat on the flywheel hub, goes along with the same idea as supercooling the key - change the dimensions of the parts to get them to seperate. We do this with pressed on pulleys all the time.

dieselgman

[Tijean]

If there is room behind the flywheel to press it further on it might leave the key behind and thus free itself. If the key started to move with the flywheel, I would consider tacking it to the shaft or somehow holding it back as you press the wheel further on. I believe the crank can be pulled with one flywheel still on but some cranks may only go out one way. If you have welded on the broken key and it failed brittle, it may be nasty hard to drill too! I dont envy your job.

[38ac]

When faced with a similar situation on our Dursey 6/1 we moved the flywheel inwards as Tijean suggested in our 20 ton shop press. Just how we rigged it would be simple to show with a picture that I don't have . You don't want to be pushing across the throw, that would bend the crank for sure. We (took me and my stout son) slid the other end of the crank down between the bed plate channels and supported the crank under the side of the throw closest to the stuck 'wheel. We then put all 20 tons on the hub using a piece of pipe that slid over the shaft. Got the torch out and started heating and by the time I told the boy "I wonder how much he,,, " WHAAM!!! Lost a few days of life I think. The hub was barely warm to the touch.

[Combustor]

Hello jfuerst,
                 Have not done this one myself, but read successful accounts---
        Method is to take a length of similar size key, centre it in a 4 jaw lathe chuck and drill it several sizes smaller than the thickness of the key. Weld an extension on to a similar drill, clamp the drilled key in the keyway as a guide and drill down the length of the stuck key. Then make a long drill about the size of the key thickness or slightly less and drill out the key. It should almost collapse at this point.Lock the shaft and try to rotate flywheel to help it collapse. A gentle pull should then be all you need.
        I may have seen this described on this site some years ago. With patience a search may bring it up. Hope this helps,   Combustor.

[jfuerst]

I knew there was knowledge out there!

The plan is to load the flywheel and crank up in the truck with the help of a small army and take it over to my "partner in crime"'s house...-> I purchased the plasma cutter, he purchased the OXY torch... Its probably a tossup as to which is easier to move, the tanks or the flywheel, if I move the flywheel and this doesn't work out there is always the chance that it falls out of the bed on the way home

Then we will install it on his press and heat the hub up with his torch while pressing it. On the way there I will pick up some dry ice and have it handy.

If that fails I will probably get all shnockered up on Mountain Dew and attempt to drill it out using the method 'Combustor' described. I had heard about this before but was missing the part about the drill guide. Building one out of a like key is obvious enough that I overlooked it.

Thanks for the great ideas... It irritates me when machinery triumphs over man out of pure stubbornness....

[dieselgman]

I'm sure that the stubborn machinery won't triumph over you. Just out-stubborn it!  Patience and then some more patience may be required though.

dieselgman