Stripped Bolt w/out removing


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Old 11-16-08, 03:57 PM
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Stripped Bolt w/out removing

I have stripped or rounded off the end tip (top two threads) of a bolt that is welded in the battery tray in my car. I can not get the nut to start going back onto it. I cant remove the bolt to replace it because it is welded to the battery tray, so I would have to replace the tray to get a new bolt. Is there anyway I could fix this at all?

I was thinking I could file down the top of the bolt but I don't know if anyone has ever done this and was curious for anyones thoughts?

Thanks
 
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Old 11-16-08, 06:00 PM
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Welcome to the forums! Figure out the size of the bolt and chase the threads with an identical die. That is what was used to form the threads in the first place. You may have luck going to a place like AutoZone and ask an associate to help you determing the size and they can either sell you the die, or, with luck, will chase for you.
 
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Old 11-16-08, 06:09 PM
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Thanks, I will do that. What does this actually do? Does it replace the current bolt or does it place something on top of it? For the looks of things on line will it re-thread the whole bolt? Thanks
 
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Old 11-17-08, 03:31 AM
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A tap and die set will cut new threads in the properly sized stock. Chasing a thread means you are using the same size die originally used, to "clean" the threads and make them usable again. the main thing is to make sure you are using the right size and the right thread [fine, coarse,etc]
 
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Old 11-17-08, 08:15 AM
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Thanks guys, should I go to Autozone or Sears for some assistance with this, don't want to mess up again? I am just so excited that there is hope. I hate that sinking feeling of, ah man I just screwed up, I've had that all weekend.
 
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Old 11-17-08, 09:09 AM
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You should go to a retailer that has the time and experience to properly identify the thread.If needed go where they sell bolts so exact comparison can be done or where they have a thread gauge.

If I was forced to choose between Autozone and Sears I'd choose Autozone instead of a department store's hardware department.

The best place is an old time hardware store with people working there that have experience.Many of these types can walk out there and ID it just by looking but they'll back that up by matching it up.

Also it would make sense to go where they sell the die.
 
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Old 11-17-08, 09:15 AM
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And just to add...
Most retail places may be happy to assist and sell you the tools, but if you could remove the tray, and take it to a machine shop with the nut, they would probably take care of it in 5 min for less than the cost of the tools to DIY.

Many places only sell tap & die kits, not individual dies.
 
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Old 11-17-08, 10:11 AM
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Originally Posted by spdavid
You should go to a retailer that has the time and experience to properly identify the thread..............
Honestly, by the time you buy a tap (actually they come in sets) and Die Set you will probably be into it for more than a new battery box would cost and you would still have an old one in your car. That is unless you can find a Harbor Freight store near you. You can get a set for around 10 bux there. I presume you will need a metric set.

An alternative approach is to get a self tapping bolt about the same size or very slightly larger and force it into the nut.
 
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Old 11-17-08, 10:34 AM
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Taps and dies are readily available seperately at any hardware store.You do not have to buy a set.All tools such as tap wrenches and die stocks are also available seperately.

A set up of all common taps and dies in SAE and metric is part of the tool section planogram for every Ace hardware in the country.

Forcing a NUT not a bolt onto the stud could work or might not and just strip the stud more making replacement of the box unavoidable.I've not heard the term self tapping applied to a nut.
 
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Old 11-17-08, 12:17 PM
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One more question. When I use the die on this bolt, am I going to have to re-thread the whole bolt or will the new top threads be able to match up with the current threads that are halfway down the neck. I am just worried that when I re-thread the top part of this bolt, the threading will not match up with the threads that are still left on it? Should this be a concern? Thanks for all the help so far
 
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Old 11-17-08, 02:09 PM
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I guess I misunderstood. The problem lies with a threadded stud or bolt, not a nut. I'm the nut. Anyway, yeah, you'll have to be careful when you thread on the die to avoid cross threading.

You could also buy a thread file and just work on the threads to straighten them out. Thread files look like thisKD Tools 2249 - File Thread Restorer SAE 8 Sizes. They must be matched to the threads on the bolt but since each thread file had 8 thread choices its pretty easy to do.
 
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Old 11-17-08, 03:12 PM
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Originally Posted by ricejd2
One more question. When I use the die on this bolt, am I going to have to re-thread the whole bolt or will the new top threads be able to match up with the current threads that are halfway down the neck. I am just worried that when I re-thread the top part of this bolt, the threading will not match up with the threads that are still left on it? Should this be a concern? Thanks for all the help so far
What you'd want to do is sort of play it by ear.You should be able to run the die down the stud part way and it will get easy for the die to thread which will mean you've hit good threads.If it doesn't get easier don't use too much force because if you need a lot of force to move the die then it's cross threading.If it's gets easier and you want to go all the way down to make sure all the threads are good you can do that but again if it starts giving you resistance be careful.
 
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Old 11-17-08, 06:09 PM
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Originally Posted by spdavid
What you'd want to do is sort of play it by ear.You should be able to run the die down the stud part way and it will get easy for the die to thread which will mean you've hit good threads.If it doesn't get easier don't use too much force because if you need a lot of force to move the die then it's cross threading.If it's gets easier and you want to go all the way down to make sure all the threads are good you can do that but again if it starts giving you resistance be careful.
Thanks, I guess I'm just going to have to give it a try and see how it works. It might be a few days before I get this done but I will let you guys know how it works out and if I have anymore questions I'll ask. Thanks for all the help
 
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Old 11-17-08, 07:23 PM
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Sorry guys if I'm getting annoying, just trying to learn about this. So when you use the die, does it strip off all the old intact threads and replace them with new ones at a slightly smaller diameter, that is the only way I can see this working? Thus I would have to get a new smaller nut to go ontop of the newly threaded bolt.
 
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Old 11-18-08, 03:38 AM
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Chasing the threads means you are basically recutting the threads in the same place. That's why David said not to 'force' it. You want to recut the threads. Cutting new threads is a lot harder to do and requires one of the better tap and dies sets. The cheap ones are great for chasing threads but aren't really stout enough to thread stock that has never been threaded.
 
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Old 11-18-08, 07:46 AM
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Just to add for clarity:This is why you want the die to be the exact same thread as your stud.You are not cutting new threads or rethreading to a different thread,you are re cutting or fixing the existing threads.If you encounter too much resistance and you are past the area of damage you may be cross-threading.

As for tool quality,I can only speak to the brand I have experience with.Ace stores carry Irwin/Hanson taps and dies.These are the same company but depending on how old it is or how long it's been in stock it could be either label.I would describe these as upper level non professional if that makes any sense.Certainly would do this job.
 
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Old 11-18-08, 10:36 AM
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Silly question. Is the stud long enough so that you can cut off the damaged end and file in a new starter thread?
 
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Old 11-18-08, 05:29 PM
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Originally Posted by cwbuff
Silly question. Is the stud long enough so that you can cut off the damaged end and file in a new starter thread?
This is not a silly question. I have been wondering how to go about doing this but I didn't know how to restart the threads? The stud is about i don't know 2 or 3 inches, plenty of room to file down.
I would feel a little more comfortable doing it this manner. How would I go about making a new starter thread?
 
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Old 11-18-08, 09:06 PM
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Originally Posted by ricejd2
How would I go about making a new starter thread?
Like I mentioned before, you can use a thread file.
 
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Old 11-20-08, 05:20 PM
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I saw that you mentioned that earlier, I was just wondering how do you work on the threads with the file, do I file the top part that is not threaded off or do I try to file the threads back? Did that make sense?
 
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Old 11-20-08, 06:02 PM
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Usually, battery boxes are in a somewhat open area so that the battery can be changed out easily and such that any acid leakage does not damage vital parts of the car.

If you are not going to REPLACE the battery box, at least remove it from the vehicle while all this thread-chasing, re-tapping, etc. is occurring. The remove/replace time will be worth it rather than operating in a confined space more slowly.
 
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Old 11-20-08, 06:09 PM
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Originally Posted by ricejd2
I saw that you mentioned that earlier, I was just wondering how do you work on the threads with the file, do I file the top part that is not threaded off or do I try to file the threads back? Did that make sense?
Thread files have hardened teeth matching the threads of the bolt. You choose one of the 8 faces available on the file and use it from the side to straighten out galled threads working your way around the bolt.
 
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Old 11-21-08, 05:56 AM
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Ricejd2 c- If you cut the stud a thread file probably won't help. If you have access to one you can try using it to clean up galled threads but if you decide to cut and redo the starter thread a set of jeweler's (also called needle files) files is probably the way to go.

The best advice I can give you on how to add a starter thread is to look at a similar size bolt and duplicate the first thread with a file. In your case it should not be difficult. Just add a small taper to the cut end and make sure the first thread has an open lead into the taper. You can use a nut of the same size and thread as a die.
 
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Old 11-21-08, 08:40 AM
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At some point you need to find out the exact thread of this stud so you can get the right tool or file for the job.
 
 

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