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Crank repair


mcraig79

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Is there any way to repair a crank with a damged flywheel side. My problem is someone who had this before tried to remove flywheel and bent the threads down. can anyplace fix that? the rods and bearings r in good shape. just wonderin if thats fixable

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Is there any way to repair a crank with a damged flywheel side. My problem is someone who had this before tried to remove flywheel and bent the threads down. can anyplace fix that? the rods and bearings r in good shape. just wonderin if thats fixable

When you say "bent the threads down" do you mean that only the threads themselves are damaged or do you mean that the threaded end of the crank is bent?

 

If the threads are damaged there is a good possibility it can be salvaged. There are two tools you can use. One is a thread file which is a small square bar that has grooves in it which exactly match the threads which are damaged. You draw the file accross the damaged threads and it straightens them out. The other is a thread repair die. It is similar to a die you would use to cut threads in a piece of round stock except it does not actually cut any metal. It just straightens out the damaged threads. Either tool is fairly cheap BTW. I have a set which includes the most common sizes in both metric and americanin both thread repair taps AND dies as well as a set of thread files and it was only $90 from Snap On! You could probably get the size you need from craftsman or if you know a Snap On dealer it would be less than $10 or so for the one size you need. It is one of my most used tools at my shop. It is also great for cleaning crud out of threaded holes or off of threaded fasteners. I would NOT use a regular thread cutting die as it will remove metal weakening the threads.

 

If it is the threaded end of the crank that is bent you are taking a chance in straightening it. It would be tough to get it perfectly straight and it may be weakend by bending it.

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as stated, first plan of attack is a thread file....start with the good threads and work your way out. they are pretty damn hard.then, if there is really bad threads on the end, you can probably get away with cutting 1, maybe 2 off, them of and finishing with a thread chase/die.

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