New use for a plasma cutter.

[gearheads78]

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.

[NONHOG]

Awesome-scared?

[gearheads78]

Originally Posted by NONHOG

Awesome-scared?

huh??

[NONHOG]

I would have been scared that the threads would be gone in an oversize freakish hole when I was done.
Never used a plasma.

[gearheads78]

Originally Posted by NONHOG

I would have been scared that the threads would be gone in an oversize freakish hole when I was done.
Never used a plasma.

I was a little worried about that too but at that point it was scrap metal anyway. I installed new consumables so the torch would be at the finest possible point. It worked great.

[bighaas79]

They make a tool kit that has little fingers that extend down into the flutes of a broken off tap so you can spin em right back out.

[crushermechanic]

a cutting torch will do the same thing. the tap will heat up faster than the metal around it. it only takes a quick burst of oxygen and the tap is gone. any more than a quick burst and you have a big hole.

[sixtyeightchevykid]

Originally Posted by bighaas79

They make a tool kit that has little fingers that extend down into the flutes of a broken off tap so you can spin em right back out.

can i get some info on this tool?
it would be pretty handy at times.

[ETsC10]

Great writeup gearheads78!

I'm sure plasma cutters are being under used by their owners and you've given us a prime example.
Next time you have a similar situation arise, please grab your camera and show us a tutorial.

bighaas79, thanks for the great tip and crushermechanic, could you elaborate?

[CowboyProtectionUnit]

OK I'm Looking at Plasma Cutters here and not wanting to jack your thread but am Curious...... What did you spend an what do you recommend for a plasma cutter??

[bighaas79]

Im not sure of the brand we have at work but did a google search for tap extractor sets, and it seems Walton is a brand/company that is popular. And they look identical to the ones i use. They are basically a center shank that has 3 or 4 "fingers" around the perimiter that slide down the center shank so you can slide them down only as far into the broken tap as you need. Use the set screw to hold the fingers at the desired depth and use your tap wrench or if you have tap sockets use it to spin the extractor. the fingers push against the flutes down inside the broken off tap giving you the leverage needed to spin them back out of the hole. They work slick and are easy to use. they make multiple sizes and for taps with either 3 or 4 flutes. A google search of walton tap extactors brings up many results of exactly what i'm talkin about.