Muffler Repair For My Friend John

[Don52]

My friend John helped me extensively with my garage addition. The nipple of his one month old muffler from his lawn mower pulled out of the muffler can.

1. Nipple broke off muffler


It appeared to be a design problem. When they tapped the rolled over collar of the can the tap nearly cut entirely through the sheet metal of the collar of the can. With the vibration of the mower the can broke off completely.

2. Thin Shell of can broke off


I decided to replace the nipple so that I could weld to a solid nipple instead of the old threaded nipple with a thin collar of sheet metal on it. The first step was to cut off the threads of the replacement nipple, using the parting tool on the lathe.

3. Cutting off nipple threads


4. Nipple threads cut off


5. Original and replacement nipple

[Don52]

The muffler can was just painted (not zinc plated or galvanized), so it was easy to remove the paint with a wire brush. I also power wire brushed the black oxide from the OD of the black pipe nipple.

6. Cleaned up and ready for welding


I welded some nubs on the nipple to keep it from falling into the can.

7. Welded numbs to support nipple in can


The bore was a little banged up from movement during the failure so I had to rotate the nipple until it sat perpendicular to the face of the can. I tack welded the nipple to the can and then I welded it out.

8. Nipple welded to can


I believe that it will last much longer than the original, which had the can that was weakened by the tapping process.

-Don

[ryanjones2150]

Good work, Don.

Nice collets in the lathe too. Metal or rubber/metal collets?

[Don52]

Good work, Don.

Nice collets in the lathe too. Metal or rubber/metal collets?

They are Jacob Rubber Flex collets. They make my 15” lathe act like a much smaller lathe.

-Don

[ryanjones2150]

I frickin love those Jacobs flex collets.

Super accurate too.

[Don52]

I frickin love those Jacobs flex collets.

Super accurate too.

For those that aren't familiar with Jacob Rubber Flex collets, they have steel blades separated by rubber. The advantage is that they are similar to ER collets because they can accommodate the entire range of possible shaft sizes instead of a few thousands on either side of the nominal, which is the case for the 5C collets. As you mentioned the runout is typically less then .0005". It is also easier to do manual operations such as sanding or filing becasue there are no chuck jaws to avoid. Here is a picture of two boxes of collets plus the chuck. Besides no longer being available from Jacobs, they are not as rigid as the 5C or ER collets. In spite of these shortcomings, I have one and use it all the time.

14. Jacob Rubber Flex D1-6 chuck


Below you can see the bars of the D1-6 style chuck mount, which retain the chuck against the taper of the spindle of the lathe. The bars also allow you to turn parts with the spindle going in reverse, without the chuck un-screwing, which was a problem with my old lathe..

15. Bars of D1-6 chuck

-Don