Shaft size

[mike1234]

I damaged threads on shaft when I removed the stator. I’m not sure if I mushroom the end a little with the puller and the end threads look a little beat up. I went to Home Depot with the nut. It seems to be a M 12 1.25 I got a M 12, 1.25 thread chaser and it’s too big anyone know what size that shaft thread is and what size thread chaser I need or any other way to try and get this nut back onto the shaft

[geoffh]

It depends on the make and model of your scoot to determine the actual size,normally a set of small files would be used to dress the threads up,but be careful that's your crank shaft and removing to much material would mean a new crankshaft

Geoff

[mike1234]

Owners manual says XS1P39QMB
It’s a eton sport

[jackrides]

Get a metric/inch vernier caliper. Doesn't have to fancy or expensive.Add a metric thread gauge and all your future thread questions will be answered. My 55 year old vernier is the greatest tool I have.

[GrumpyUnk]

To use a thread chaser, you need to have a good starting point. If you used a 'die' of the same size M12 x 1.5, it would start out sort of loose as it would normally be cutting into a shaft that had NO threads. The tigher, more exact fit size threads would follow the original cutting edge as you rotate the die.
Get a good magnifying glass/light so you can see the individual threads of the original. Use a triangular file and run it gently down the place where there was a groove originally. It will NOT be perfect. Take a few passes at the start of the threads, and remove any mushed over thread so the groove is clear. Remove nothing else yet. See if the nut will start on the bit of thread you have cleaned up. If so, continue further down the threaded area following the groove. If the nut did NOT want to thread on, look closely at the threads to see if you can determine whether the groove is clear enough or the adjoining thread has been bashed/damaged, and remove as little material as you can until you can start the nut. Do the same thing all the way down to good threads.
IF the end is really damaged, you may have to file off the old threads starting at the end, until you can get the nut to start engaging. As long as you have sufficient threads left to fully engage the nut you should be fine.
TAKE YOUR TIME. Do not remove a lot of thread, but just little bits as you proceed. If the nut starts to thread, but is difficult, remove it and examine the threads/grooves where you think it has been engaging. You will likely find a raised bit of thread, or a bit of junk in the groove. Remove as needed, and try again.
It is a slow process, but a lot quicker and cheaper than buying a new crankshaft. One other possibility is to thread to a smaller size and use a smaller nut. Better to maintain what you have, being stronger and also quicker to do.
tom

[FrankenMech]

A die or thread chaser may cut a new thread and ruin the crankshaft. Follow the directions above and work slowly and carefully using the magnifying glass. Start out working with the good thread and work outwards. If more than a couple threads have been damaged the crankshaft may be shot.

BTW- Home Depot is NOT a hardware store. Go to a real hardware store.

Original post: 49ccscoot.proboards.com/thread/31440/stator-nut