Plasma cutter to the rescue
October 2nd, 2011, 07:41 PM
#1
car guy
Thread Starter
Join Date: Apr 2008
Location: Dallas TX
Posts: 5,659
Plasma cutter to the rescue
When I bought my plasma a few years ago it was as a want more than a need. I talked with a few people that had them that even said don't get it because they never use it.
I did not listen and I am so glad of that. I find it one of the most used tools in my shop I use it all the time. It is truly one of my favorite tools.
Fast forward to last night. I was working on a set of 396 exhaust manifolds for a big block Caprice with the typical rusted and broken off studs. My normal method is weld a nut to whats left of a stud and the heat lets me use the nut to back out the broken stud. After several attempts all I was doing is breaking the studs shorter and shorter. Plan B was drill out and retap. I ground the studs flush and drilled a pilot hole as close to center as I could. I worked my way up to 5/16 hole so I could re-tap to the 3/8 stud size. This seamed to be working fine. The hardest part was keeping the hole centered so I was drilling only the old stud and not the cast iron manifold.
I got two of the holes tapped clean and disaster happened. As I was tapping the last hole and the
tap broke. It was sticking out about 1/2" so I tried grabbing on with vise grips and all it did was shatter the brittle tap down below the surface. I ruined a few small chisles getting little piece chipped off at a time hoping it would shatter and fall apart. NO!! I tried building up a little mountain of weld to have something to twist it out but it would break a little piece off and leave the rest jammed in there.
At this point I had been at it for over an hour and I was pretty much ready to throw the manifold in the scrap pile. I went inside for the night looked on craigslist and ebay. The cheapest one I can find was $150.00 plus freight and it had studs broken off just like mine. I was thinking about options. I know you can buy special drill bit that will drill the tap but they are 50.00-75.00each and very very brittle. A tiny bit of side load and they snap off. Without a jig and a heavy duty drill press it near impossible to do.
So brain storming in the middle of the night it hit me. How about carefully blowing it out with the plasma cutter. I tried it tonight and with in 5 min I had a hole tapped and ready for a stud. Next time I am pulling the plasma out first.
I did not listen and I am so glad of that. I find it one of the most used tools in my shop I use it all the time. It is truly one of my favorite tools.
Fast forward to last night. I was working on a set of 396 exhaust manifolds for a big block Caprice with the typical rusted and broken off studs. My normal method is weld a nut to whats left of a stud and the heat lets me use the nut to back out the broken stud. After several attempts all I was doing is breaking the studs shorter and shorter. Plan B was drill out and retap. I ground the studs flush and drilled a pilot hole as close to center as I could. I worked my way up to 5/16 hole so I could re-tap to the 3/8 stud size. This seamed to be working fine. The hardest part was keeping the hole centered so I was drilling only the old stud and not the cast iron manifold.
I got two of the holes tapped clean and disaster happened. As I was tapping the last hole and the
tap broke. It was sticking out about 1/2" so I tried grabbing on with vise grips and all it did was shatter the brittle tap down below the surface. I ruined a few small chisles getting little piece chipped off at a time hoping it would shatter and fall apart. NO!! I tried building up a little mountain of weld to have something to twist it out but it would break a little piece off and leave the rest jammed in there. At this point I had been at it for over an hour and I was pretty much ready to throw the manifold in the scrap pile. I went inside for the night looked on craigslist and ebay. The cheapest one I can find was $150.00 plus freight and it had studs broken off just like mine. I was thinking about options. I know you can buy special drill bit that will drill the tap but they are 50.00-75.00each and very very brittle. A tiny bit of side load and they snap off. Without a jig and a heavy duty drill press it near impossible to do.
So brain storming in the middle of the night it hit me. How about carefully blowing it out with the plasma cutter. I tried it tonight and with in 5 min I had a hole tapped and ready for a stud. Next time I am pulling the plasma out first.
October 3rd, 2011, 07:33 AM
#4
car guy
Thread Starter
Join Date: Apr 2008
Location: Dallas TX
Posts: 5,659
LOL I went from totally pissed off the night before to overjoyed. I am trying to put this car together to make a little money and its nickel and diming me to death. At this point I will be lucky to make $500.00 out of my $5000.00 worth of labor I will have put in it.
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