Stripped Threads

NCmau · Mar 30, 2015

This may not be related to MF machines but since I am using a lawnmower deck mounted in front of my loader bucket, I hope it will slide.
This deck is powered by a 12HP BS (aluminum block). The 1” hole for the muffler pipe is stripped. There are no other fastening holes for a muffler pipe. I tried to rethread the hole with a tap, but it just doesn’t hold.
I like to hear some suggestions. I was thinking of plumber rope or muffler putty kit… but maybe there are better solutions.

BigMarv1085 · Mar 30, 2015

you could try a heli coil, might be hard to find and pr
icey

maxwell99 · Mar 30, 2015

Are there enough threads left in the block for you to wrap Al foil around the muffler
threads.

If so, wrap three or four wraps then try to screw the muffler into the block.

Might be a muffler seal out there, coat it, screw it in,, then let it set and harden.

Phil Tibbetts · Mar 30, 2015

I doubt that it can be repaired but if it can you need what is called a short taper pipe tap. They are used in shallow holes. You can cut off a regular tap with a disc cutting wheel. A regular pipe tap needs to go in about 3/4 of the thread length for a standard pipe fitting. It is more detailed than I can get into here.

FBH44 · Mar 31, 2015

Find the best NAPA store [ they are various and different ] and go ask the oldest old guy for his advice.

NCmau · Mar 31, 2015

(quoted from post at 17:51:47 03/30/15) Are there enough threads left in the block for you to wrap Al foil around the muffler
threads.

If so, wrap three or four wraps then try to screw the muffler into the block.

Might be a muffler seal out there, coat it, screw it in,, then let it set and harden.

There are few threads but not enough to hold it when running. I guess it wouldn't hurt to use, at first, aluminum foil and muffler seal as you suggested. If that doesn't work then I move to plan B.
Thanks.

Our Farmer · Apr 3, 2015

Stick it in there as best you can, then braze it.

ASEguy · Apr 10, 2015

On my 67 10 horse briggs my muffler was loose where it threaded in so I got a big nut from an electrical supply house and wrapped tin foil around the threaded pipe going into the muffler. After I threaded it in I cinched it down with the big nut and it worked. That's been 3 years ago.

NCmau · Apr 10, 2015

(quoted from post at 10:06:04 04/10/15) On my 67 10 horse briggs my muffler was loose where it threaded in so I got a big nut from an electrical supply house and wrapped tin foil around the threaded pipe going into the muffler. After I threaded it in I cinched it down with the big nut and it worked. That's been 3 years ago.

Yes that's a good option. I used that years ago with a 5hp and it worked well. On this one, however, there are very few threads left and I am not sure the nut is going to work. But I will give it a try when I get back to the project. Thanks.

ObsoElitist · Apr 10, 2015

(quoted from post at 07:25:22 04/03/15) Stick it in there as best you can, then braze it.

Braze aluminum? Please tell me how to do that.
if there is enough metal, the best solution would be to go up one size and use a hex bushing. Welding would probably damage things unless the head was removed, stripped and pre-heated..

BruceKP · Apr 19, 2015

(quoted from post at 07:52:15 03/30/15) This may not be related to MF machines but since I am using a lawnmower deck mounted in front of my loader bucket, I hope it will slide.
This deck is powered by a 12HP BS (aluminum block). The 1” hole for the muffler pipe is stripped. There are no other fastening holes for a muffler pipe. I tried to rethread the hole with a tap, but it just doesn’t hold.
I like to hear some suggestions. I was thinking of plumber rope or muffler putty kit… but maybe there are better solutions.

Goto Harbor Freight. They have an aluminum rod that will flow with a map gas torch. It is awesome stuff.

NCmau · Apr 20, 2015

[/quote]

What would be the best way to apply it?

BruceKP · Apr 20, 2015

(quoted from post at 05:28:53 04/20/15)

Goto Harbor Freight. They have an aluminum rod that will flow with a map gas torch. It is awesome stuff.[/quote]

Just like solder. You can us a propane torch. Wire brush the area. Heat with the torch. The rod melts before the base aluminum gets to hot. See a demo on youtube at;
https://www.youtube.com/watch?v=aiThO-UQIWE
I use Map Gas . just like Propane but hotter. You can even plug the hole, re drill and tap. Practice on junk first.
Good luck.

NCmau · Apr 20, 2015

Just like solder. You can us a propane torch. Wire brush the area. Heat with the torch. The rod melts before the base aluminum gets to hot. See a demo on youtube at;
https://www.youtube.com/watch?v=aiThO-UQIWE
I use Map Gas . just like Propane but hotter. You can even plug the hole, re drill and tap. Practice on junk first.
Good luck.[/quote]

I saw the video. Definitely good stuff. Thanks for the tip.

Stripped Threads

NCmau

Member

BigMarv1085

Member

maxwell99

Well-known Member

Phil Tibbetts

Well-known Member

FBH44

Well-known Member

NCmau

Member

Our Farmer

Member

ASEguy

Well-known Member

NCmau

Member

ObsoElitist

Member

BruceKP

New User

NCmau

Member

BruceKP

New User

NCmau

Member

Similar threads