K301 Threaded exhaust elbow

[finsruskw]

New threads on a repaired elbow. Can only get a couple turns into the block.
What would be a good sealant to use to keep from leaking?

[J-Mech]

Depending on the model, 2 turns in won't hold. It will just rip out the threads. I'd try a better repair, or replace the elbow.

[Sam Mac]

I'd check the threads in the block. You can use a pipe that is the same size to see if it goes in more than 2 turns. If it does the problem is with your elbow. If not you may need to get or borrow a tap to clean up the threads in the block. If the problem is with the elbow you'll need to replace or repair the elbow. The threads on the elbow can be cleaned up with a die of the proper size. Any decent plumber should have the tap and die to fix you up.

[finsruskw]

What I did was cut the threaded portion plus a little meat from a double wall nipple. After screwing the elbow in a coupling to assure it being straight, I cut the damaged threads off square in a band saw. then welded the new end to the elbow making sure it was square and the same length as before, useing another elbow as a guide. It also has messed up threads, both having been welded to a block.

There is not much left for threads in the block, unfortunately, and the repaired elbow slips in a ways before the threads catch. Same for a new nipple also.

I'll have to see about a tap to clean up what's left in the block I guess, if possible.

[ol'George]

You can cheat a little:
A plumber or anyone with a pipe thread machine can set the die loose and make a larger diameter thread on the nipple after you chase the thread in the block with a pipe tap, that should get you a good fit with plenty of threads. BTDT

[Yosemite Sam]

Originally Posted by ol'George

You can cheat a little:
A plumber or anyone with a pipe thread machine can set the die loose and make a larger diameter thread on the nipple after you chase the thread in the block with a pipe tap, that should get you a good fit with plenty of threads. BTDT

Capital idea George!