Exhaust Stud broke off

This is interesting - I never knew 'cleaning' a thread with a regular tap or die
was a no- no. Now looking to get myself a tap former/chaser for M6 x1. Is it the case that 'fluteless' taps are all formers ?

Cheers.

 

I'm no expert, but that would seem to be the gist of it. I guess where you have enough thread to give the tool some 'grip' it will want to follow that established path rather than cut a new one.

 

The exhaust studs are pretty much the same for all the xj's. I have a whole box full of them off of various bikes I've parted out. Regardless of part #, they're all the same, other than some being slightly different lengths, but THAT doesn't make a difference---thread it in til it stops, torque it, put the collar on, and put the nut on......which BTW, the nuts are all the same, too-----yup, the box has has a lot of those in it too..........

For the fellow that is contemplating filling the hole----- yeah, he WOULD need a tap. If he's FILLING the hole, he'll have to drill it and then re-tap to the correct size and thread.

If the hole damage is big enough......how about 'propping the stud in place and building the aluminum weld right around it! THEN it'll never come out....just be aware of that in the future......lol

BTW, there have been posts in the past about some shops that can now remove studs like that with a procedure that destroys the stud without damaging the aluminum. It's done sonically, I think, but I can't for the life of me find the link or think of the term. It's kind of an interferometry type of thing-----


dave

 

EDM. Electrical Discharge Machining. The fastener is eaten away by a small, high-voltage arc.

 

The flute in a tap is there to provide a path for swarf to be removed without having to back the tap all of the way out, but it also makes for a weaker tap.
Fluteless taps are not thread reformers.
No matter what, a tap is not a chase, and it is not a thread reformer.
Taps have sharp cutting edges that remove material. They have one job, cutting threads into a new hole. Using one to clean up, or reform threads is a dicy procedure because you'll be removing material from an already weakened/damaged thread.

 

Not sure if you got the remaining stud out of the block. If not, don't try and drill and tap it out. Instead, take it to a welder and have them weld a welding stick to it and back it out that way. Then, you could use a heli-coil if the threads are damaged. Although, it's best to keep the threads undamaged and get a new stud.

Good luck. I've been there before and it's not a lot of fun.

 

a little read on taps and chasers
http://www.practicalmachinist.com/vb/ge ... ap-237679/

 

Thank you - I am now fully informed. Confused as hell, but fully informed..