Anybody have advice for creating chasing tap/die

[bigtiller]

I'm not sure a tap or die would work for the OP. It sounds like he still has some threads showing but they are damaged. A thread chaser is basically a worn out tap/die and I think that may be just the ticket for the job.

 

[SPYDERLK]

I'm not sure a tap or die would work for the OP. It sounds like he still has some threads showing but they are damaged. A thread chaser is basically a worn out tap/die and I think that may be just the ticket for the job.

Yes. In a case like that the thread forming taps linked are ideal because they will push the metal of the remaining thread back into correct shape without cutting it.

,,,,,,,,,,,,After thorough cleaning use one of these with moly on it to force everything back were its supposed to be.

McMaster-Carr

 

[QueBota]

Quick update, had some more time to work on this. There were virtually no threads left in the bores of the exhaust manifold ears, just a trace of where they used to be. As I said earlier the bolts came out hot, my father (RIP) and other old timers I know would have said we "burnt" the bolts taking them out. We kept them drenched in Kroil backing them out but the combination of rust and old threads on the bolts wiped the threads from the manifold ear bolts.

We went with slightly under size fasteners with nuts on the bottom. Very little clearance to drop the new fasteners through the bores and into the ears of the Y pipe flange. Difficult to get a wrench on the inside bolt heads to enable torquing. Obvious now why they had threaded the bores on the ears.

Job is done, should last longer than the truck. Just glad the bolts didn't snap off on during removal. Would have been left with the difficult task of trying to remove the broken off studs from the ears, with either a stud remover, drilling them out or burning them out with oxy/acty. Didn't want to pull the exhaust manifolds, I'm sure that would have turned into another project.

Walker sells a replacement fastener kit for about $15.00 a side Amazon.com: Walker 36129 Hardware Spring Bolt Kit: Automotive, looks nice but we just used fasteners from my shop.

Thanks,
Q