Crankshaft threads damaged!!!!

[Ecarta]

Well I have reached a severe problem.

Clutch side crankshaft threads got buggered up. I got a die to repair the threads. But it just stops after 1 revolution. Like it's stuck bad. It appears to be square on the shaft though.
I'm using an M16 X 1.0mm die.

But how much effing torque do I use the force the die onto the crankshaft? Too much I risk ruining the crankshaft, that would be a $300-$500 mistake I can't afford right now. But Too little and it won't cut the threads.

I can't believe 2 buggered up threads are holding up this whole rebuild!

Any suggestion???

Thank you in advance!

[Slick_Nick]

That thread can be single point cut. I've repaired much worse. A die is not the way to go. The threads are too badly damaged that there is no way for the die to go on straight. You will either ruin the crankshaft more, or get your die stuck on or snapped off on that thread. Don't risk it.

You're not gonna like it, but it's going to require that the crank be removed and disassembled so the crank web can be chucked up in a lathe. Use this opportunity to throw a new rod kit in it, and enjoy it for years to come.

[Goat]

Oh man! I was wondering what a machinist might say.
It looked like it might not be easy as a die for chaser.
Sorry to see this.

[pumpguy]

Before you resort to Slick Nick's recommendation, which I endorse by the way, you might try using a metric thread restoring file.

In case you're not familiar with these, thread restoring files are available in both metric and imperial thread pitches and have 8 different pitches on each file. Check that the file you buy has the same pitch as what you're trying to fix.

Thread files are very useful tools so it won't be a one time use only purchase. And, you won't make the threads any worse than they are now.

Good luck with this project.

[SS109]

Before you resort to Slick Nick's recommendation, which I endorse by the way, you might try using a metric thread restoring file.

In case you're not familiar with these, thread restoring files are available in both metric and imperial thread pitches and have 8 different pitches on each file. Check that the file you buy has the same pitch as what you're trying to fix.

Thread files are very useful tools so it won't be a one time use only purchase. And, you won't make the threads any worse than they are now.

Good luck with this project.

I agree, Nick's suggestion is the best. However, I have dressed damaged threads with thread files before myself with good success. Ecarta, just take your time and you probably won't have to split the cases.

[KDXGarage]

try a thread file

Also, a reshaping die, not a thread cutting die.

[Ecarta]

try a thread file

Also, a reshaping die, not a thread cutting die.

Say more about that. I can't seem to find a reshaping die.

[KDXGarage]

Lang may make what will work.

example of files:

https://www.langtools.com/sku-2573-3-pc ... -file-set/

example of dies I am referring to:

https://www.langtools.com/sku-801-7-pc- ... torer-kit/

Click around on the Lang site. They may have just the one part you need.

[pumpguy]

There are also thread restoring tools that look kind of like a C clamp with a soft wide angle V on the anvil side and the thread cutter tool on the screw side. The cutting tool has maybe 6 teeth of the particular thread pitch you need to restore. These tools come with various pitch cutters that you attach to the screw side.

Nice thing about this tool is the diameter doesn't matter, only the pitch of the thread you need to clean up.

We used these a lot on buggered up bearing lock nut threads on large pump shafts. I think OTC was the manufacturer.