How have you fixed twisted off rusty bolts?

[EuroDat]

Hi Mike, If you have one of those helicoil kits with 10 helicoils and 1 tap, be carefull with the tap. Its not made of top quality metal and can break with little effort.

Back it off every 1/4 or 1/8 turn and use plenty of lube.

I also use loctite on the helicoil as a precaution on holes that dont bottom out. Dont want the helicoil screwing through to the other side. I have had that happen. We used the original bolt from another car, but on grabbed the helicoil and screwed it through. Took a lot of work to get it out.

Chas

Edited September 14, 2013 by EuroDat

[grannyknot]

Hey Mike, I'm not saying you did anything wrong, I would just like to repeat something my 70 yr old metalwork high school teacher back in 1973 told us. "When you tap or drill a hole you are the milling machine, but you are not as accurate so go slow with lots of lube, just like a woman." At 13 we laughed but didn't really know what he was talking about.

Proper proceduer was, turn the tap in 1/8th turn then back off 1/4 turn to allow the cuttings to fall and keep advancing and retreating slowly until you are all the way through, slow and precise. It occured to me that taps and dies are still sold but no one ever mentions how to use them.

Chris

[Mikes Z car]

EuroDat and Grannyknot,

Thanks! I will print what you two said about going extremely slow with the tap and tape it to the tap kit I have. You two probably saved me from breaking another tap. I wondered if the coil might turn itself out with the bolt, I will be using locktite on it. Great idea.

Here is a picture of the weld on the sheet metal after the nut was welded on. I may redo what is visible here though I think the nut got welded on better since the bolt tightened down fine. I was laying on the sidewalk holding a flashlight to do this last part on the sheet metal. Mr. Lincoln Welder is probably turning over in his grave.

(File name should read after welding drivers side nut)

Edited September 15, 2013 by Mikes Z car

[bartsscooterservice]

Think it might be a good precautionary idea to have a propane torch and penetrating fluid to soak and heat up the surrounding areas before attempting to unscrew?

Yes, heating up the old and using some wd40 or penetrating oil will most likely get it out. Forget cold. That's what I usually do to. But I would never use a helicoil. For my work I regularly need to drill out broken of 8.8 strenght bolts into cylinders all the time. What I do is grind it down to the surface, then use a pointer with hammer to center, then use a HSS drill, start small and go to the right size, then use a tap to make new thread.

[EuroDat]

Here is a picture of the weld on the sheet metal after the nut was welded on. I may redo what is visible here though I think the nut got welded on better since the bolt tightened down fine. I was laying on the sidewalk holding a flashlight to do this last part on the sheet metal. Mr. Lincoln Welder is probably turning over in his grave.

[ATTACH=CONFIG]65991[/ATTACH]

(File name should read after welding drivers side nut)

Mike, I'm glad its not structural. Thats the problem when you are welding thin metal and its upside down making the degree of difficulty even worse. It doesnt need much to hold it together, but I think I would try to get welded.

I can welded ok;) but when its a PITA like this I get a friend who is an excellent welder to do it. Just have to put up with his remarks over my welding.

Something else to keep in mind if you use a helicoil.

The helicoil will probably be to long for the nut you are fixing. When you break off the tag (by turning the tool 90degrees and punching it through) it might push the helicoil through and stretch it out like a spring.

Check the length of the helicoil versus the tapped out nut and make sure the helicoil is a little shorter than the nut. If its not, then remove enough coils so it will be.

Chas

[ajmcforester]

EuroDat and Grannyknot,

Thanks! I will print what you two said about going extremely slow with the tap and tape it to the tap kit I have. You two probably saved me from breaking another tap. I wondered if the coil might turn itself out with the bolt, I will be using locktite on it. Great idea.

Here is a picture of the weld on the sheet metal after the nut was welded on. I may redo what is visible here though I think the nut got welded on better since the bolt tightened down fine. I was laying on the sidewalk holding a flashlight to do this last part on the sheet metal. Mr. Lincoln Welder is probably turning over in his grave.

[ATTACH=CONFIG]65991[/ATTACH]

(File name should read after welding drivers side nut)

Big welding tip, keep some scrap metal around and warmup by welding your scrap together, and getting the settings right. I can weld with the pros after 45 min to hour of warming up. Who knows maybe you can sell the scrap as art one day.

Helicoils can work well I have been able to not use any on my Z. I did use them on my old tuck do to the factory cross threading some things on the block and starter. Trick to using them that found was to use a punch and punch the material in opposite sides of the coil so it can't twist anymore then tap the coil to make sure their is no pinch points. Just be careful using the punch because the metal your smashing together normally has different hardness and your part can suffer more than the coil

[Mikes Z car]

bartsscooterservice,

Nice idea to keep the original size thread. Grinding off the bolt would have worked for me on the driver's side bolt (didn't know about the grinding off idea). The passenger side bolt was shrouded by the fender and the fender didn't want to pull a few inches out of the way over the sticking out broken off bolt for some reason.

EuroDat,

I am also glad the repair is not structural! I know where I can get a proper welding job. I won't mind putting up with any comments about my welding, maybe they will look at it as a compliment on how they weld. That is a great idea on shortening the helicoil to the size of the nut. I had already put the helicoil in on the passenger side (welding worked on the driver's side) before I read your post. I put a couple of practice helcoils part way in to make sure they would go in okay before I put the loctite on and the tag broke off more easily than I would have thought just by turning. Both practice helicoils got stuck and didn't want to unscrew, maybe because the coil pushes out on the threads when unscrewing and/or because I didn't shorten the helicoil to the size of the nut. Both of their tags broke off, had to pull them out with pliers. Maybe some tags are easier to break off than others. The tap turned freely in the new threads before putting the practice helicoils in. Next I get to break the tag and put the bolt in.

ajmcforester,

Great idea on warming up to a welding task VIA a scrap of metal. I will put a piece of scrap metal with the welder and do that next time I weld.

I guess this is related, I was just told that for exhaust bolts an acetylene torch can be used on the bolt because the bolt will flow out of the hole leaving the threads intact in the block metal.

Edited September 18, 2013 by Mikes Z car

[Patcon]

Mikes Z car:

What kind of welder were you using? MIG? Shielding gas or flux core? What amperage welder?

Charles

[Mikes Z car]

Patcon,

It is a Lincoln "handy mig" with two switches which give four amperages. The box says it is good for between 35 and 88 amps. I have a pure argon tank I use for the shielding gas and I can hear the gas coming out of the end of the "wand" when I pull the trigger to weld. The wire is set to a slow speed, about a "2" on the speed dial that goes up to "10". I use the next to the highest amp setting, I have never used the maximum amperage setting as I have been afraid of blowing holes in the sheet metal. I may be being overly cautious. Didn't want to put a hole in the z car.

[Patcon]

I had a century 100 amp welder at one time and it welded like a "drunk monkey". I bought myself a Hobart 230 last year for Christmas. Much easier to weld with a good welder especially if it can be run at 100% duty cycle. I have lots of ideas for your welds but it is much easier to figure out by feel. Sometimes I get little beads like that when my heat isn't high enough, metal is too dirty or not enough shielding gas. I usually run at the highest setting I can with out burning holes. You can also avoid holes by triggering in short burst and not holding the torch square to the surface. If the metal gets red hot the shield gas can blow holes in it. I have found on my Z I use the #1 and #2 settings on my welder out of 12 settings. The metal is very thin and it is easy to blow holes in it especially if it is on a panel that got stretched a lot when it was stamped.

My speed setting is about 22-28 on those first 2 settings which I think is inches per minute (?). I like it to sound like frying bacon real consistent sizzle and very little popping. Generally when I am getting popping it is because the metal is dirty or rusty. A little die grinder with a 2" 36 grit rowlock pad works good for this and quick. Praticing on a test panel to find some initial settings is a good idea preferably a Z panel because the alloy and the gauge will be similar. My 2 cents...

Charles

[Captain Obvious]

I have a pure argon tank I use for the shielding gas

You're using the wrong shielding gas. For general purpose MIG on carbon steel, you should run 75% CO2 / 25% argon mix. If you use 100% argon with the MIG, you get proud beads and very narrow fingerlike penetration. You'll be tempted to turn the power up to get the bead to spread, but that's not the solution. The solution is to use the correct shielding gas.

I went through this myself about a year ago because I was trying to minimize the number of bottles I had to maintain. I figured that I could share the same 100% argon bottle between the MIG and the TIG, and I was mistaken. It doesn't work right.

[Mikes Z car]

Patcon,

Thanks for typing those tips in, I watched some videos on welding but they didn't mention techniques that you did. I don't know if a better welder is an option for me (for one, don't have a ready access to 230V) but for the work I need to do a crappy one might be okay especially if I can improve technique. I'll clean the rust off of the metal next time. I mostly get popping, not sizzling so I know the arc isn't sustaining well.

Captain Obvious,

I will get a bottle of the CO2/argon mix, thanks for pointing out the effect of the gas.

Just when I thought I didn't know anything about welding it turns out I was right.