another engine question

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anickode

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Well, cant get it to shatter..sounds like im getting a new crankshaft:(

And next time, buy a 60¢ bolt that fits your crankshaft instead of trying to modify your crankshaft to fit a 60¢ bolt. Keep trying though. It won't shatter like ice, it will come out one small chip at a time.

---------- Post added at 08:29 PM ---------- Previous post was at 08:28 PM ----------

What were you using to turn the tap?
 

itsid

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Hmm, there are four flutes on a tap..
if you can fit some sewing needls in two of them or maybe even small hardened nails, maybe you can generate enough torque (with pliers) to back it out just enough to grab the tap with said pliers to get it out not harming the thread.
Just don't tap the needles in, if they do not slide in the flutes, leave it be!

also aluminium is expanding quicker than steel, so some gentle heat around the bore might help.
And add large amounts of penetrating oil to reduce the friction whereever possible.

I was once lucky enough it failed on many occasions more though..
Anyways, maybe you're lucky too :D

'sid
 

anickode

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Hmm, there are four flutes on a tap..
if you can fit some sewing needls in two of them or maybe even small hardened nails, maybe you can generate enough torque (with pliers) to back it out just enough to grab the tap with said pliers to get it out not harming the thread.
Just don't tap the needles in, if they do not slide in the flutes, leave it be!

also aluminium is expanding quicker than steel, so some gentle heat around the bore might help.
And add large amounts of penetrating oil to reduce the friction whereever possible.

I was once lucky enough it failed on many occasions more though..
Anyways, maybe you're lucky too :D

'sid

Aluminum crankshaft... That's a new one :roflol:
 

anickode

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Another method that could be implemented, while risky, only MIGHT destroy your crankshaft, but as a last ditch effort, may be worth it. I only thought of it because itsid said something about aluminum.

Disassemble the engine. Stand the crankshaft on end in a vise or something. Put the crankshaft in a heavy duty plastic bag and gather the neck of the bag around the output shaft. Wrap it tight with electrical tape, so only the end of the shaft with the hole where your tap is broken off shows.

Put on some chemical gloves and a face shield and using a pipette, Fill that hole with 70% lab grade nitric acid until the broken tap is submerged. It will bubble. This is because the nitric acid will attack any steel surface and dissolve it. When the bubbling stops, pour out the black nasty liquid into a big pail of water to dilute it to a safe PH for disposal down the sink. Flush out the hole with clean water and try to remove the tap with a needle nose pliers. Repeat the process if necessary.

Typically this is only done in aluminum or stainless steel parts as the nitric acid will attack any steel it touches. (Thus why you encapsulate the rest of the crankshaft in plastic). In this case, the tap will shrink and the hole will enlarge. Not really ideal, but then you have a shot at redrilling the hole one size up and going with a bigger diameter bolt. It might destroy your crankshaft, but you might be able to salvage it. And either way, you will have learned a useful method for efficiently removing broken bolts, drills, and taps from aluminum and stainless. I have used this method for removing broken off head bolts that were seized in an aluminum engine block.
 

itsid

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OOPS.. hehe..
yeah missed that shaft part (my fault), forgive me that was a 4:00am post..

but don't mock me for YOU not being able to spell Aluminium! (your fault) :lolgoku:

Now, back to backing out a tap..
how about tapping it... (your language not mine...)
with a hammer that is (or mallet).. a punch might be too big, but a hardened nail (again?)
point the tip at one flute, light gentle taps.. next flute, rinse repeat....
takes patience and a lot thereof... but it can work and it'll keep the shaft alive for sure.

tomato!
'sid

PS side note:
http://www.waltontools.com/products/remvtap.htm
look.. a sewing needle style extractor.. commercially available....
 
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