Making large threads

cathead

CATWERKS LTD
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Feb 7, 2013
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A friend of mine has a large compactor that needed some help. The threads on the end of the 3 foot long cylinder with a 6 inch diameter bore
were stripped out. Since I wasn't able to turn the cylinder with my lathe, we decided to make some new threads on a piece of DOM(drawn
over mandrel and weld it on to the existing cylinder. I started by rethreading the "nut" part first so I could machine threads on the DOM
to fit the new larger diameter threads. I took my time to get a good fit and did a little hand filing to finish up.

Here it is ready to cut off and chamfer for welding.
P1030865.JPG


It looks like the threads are about 6.75 inches or so.
P1030862.JPG

P1030864.JPG
Tomorrow I have to look at the project to determine where to cut off the new threaded piece that will be welded on. It turns out that the cylinder rod was
plenty long so we would be able to lengthen the cylinder a bit. I would guess the new threaded piece will have to be honed if the piston gets into the added piece. All in all it was a fun project in the shop today.
 
Wow. Big work. Yes, I hope the piston doesn't cross the weld?
 
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