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Post by C Monster on Sept 28, 2012 8:59:10 GMT -4
whats your info on the Subject and how do you clean / fix old threads whats your best and easiest way to do it Do you use tap and tie or re threader/ chaser
I was thinking it wood be a good place for some info I have use both ways I recently installed the highlift on the hood... Excellent place to put it, aside from three considerations. 1) washer nozzle has to be adjusted down so it washes the window and not the bottom of the jack. 2) the hood no longer lays across the windshield when open due to the brackets. 3) it takes some visual getting used to with it just sitting up there. I did however have to retap all six holes for the hinges as the new bolts would not go smoothly into the dirty holes. So I taught myself to use the tap & die tools. If anyone was wondering, the hinge bolts are M8 x 1.25. All in all I am happy with the placement. Got the brake line done in the front as well tap and ties are for making new thread Do not use a tap or die.for fixing threads it open the threads up too much and you end up with mess up the threads and you have to helicoils them, you should have bought a thread chaser/re threader set thats what is used for fixing and cleaning up old threads
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Post by SocialWheeler on Sept 28, 2012 9:35:52 GMT -4
Interesting. I did not know that, so I am lucky then that I did not totally screw up the holes trying to clean them out. Thanks man, I dodged a bullet there then, as the bolts went in nice and easy and tight.
I also learned about bending hard brake lines, cutting tube and making that little flared thing at the end of the tube. Glad Scott was there for that. Not sure my tiny mechanical mind would have been up to it.
We also did the manifold bolts on the '03... it was just as hateful a job as it was on my '05. ;D But not the worst job ever.
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Creepy
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Post by Creepy on Sept 28, 2012 15:51:32 GMT -4
Do not use a tap and or die.for fixing threads it open the threads up too much and you end up with mess up the threads Tap OR die. You don't use both. (tap is for internal threads, die is for external.) Len likes to use the right terms, if you are correcting nomenclature, get it right. Running a tap thru a damaged thread may knock material off the minor diameter of the threads, making the hole feel looser. You lose the 70% perfect thread engagement that you would have had from a perfectly drilled and tapped hole. The load it can hold goes down. The advice to use a thread chaser is fine, but it is not necessary. I have never used a thread chaser, except a couple of times on spark plug holes. We have an entire tap and stud department at work, no thread chasers. Just new sharp taps. You can't add material, only take it away. A threaded hole that needs a tap run thru it is already damaged. A thread chaser only attempts to smoosh some material back to damaged areas of the thread. this material usually isn't attached very well to anything, and the threaded connection will be weak and prone to strip. Chasers are more of a thread deburring tool. Which may have possibly been the correct tool for the job, but I felt the need to add more info regarding your statement that running a tap thru a threaded hole will mess up the threads. This is simply not correct.
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Post by C Monster on Sept 28, 2012 15:59:09 GMT -4
!just more imfo on the tap vs re threader
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Post by SocialWheeler on Sept 28, 2012 17:27:48 GMT -4
What I did was deduce what the bolt size and pitch (is this right?) was, and then I carefully screwed this into the hole, being sure to go slow and not force it. What I ended up with was six holes that the bolts screwed tightly into. It felt like I was putting them into a brand new hole. Very smooth and tight. I even held the tool in my left hand so it felt like someone else was doing the work. So you are telling me that the load bearing ability is decreased... Am I in danger of losing the jack at some point, or is the reduction in this load-bearing ability not of a material amount? It seems tight and secure.
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Post by C Monster on Sept 28, 2012 17:53:06 GMT -4
What I did was deduce what the bolt size and pitch (is this right?) was, and then I carefully screwed this into the hole, being sure to go slow and not force it. What I ended up with was six holes that the bolts screwed tightly into. It felt like I was putting them into a brand new hole. Very smooth and tight. I even held the tool in my left hand so it felt like someone else was doing the work. So you are telling me that the load bearing ability is decreased... Am I in danger of losing the jack at some point, or is the reduction in this load-bearing ability not of a material amount? It seems tight and secure. you'll be ok the way you did it if the bolts tighten up good. than you are ok it was just a FIY that's not what Taps and dies are made for ;D
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Creepy
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Post by Creepy on Sept 28, 2012 18:40:53 GMT -4
diameter and pitch, correct. what you did is exactly what I would have done. Using oil, run the tap thru to clean the threads, but not use much force, and stop if you start removing material. Keep going if its working fine and the bolts fit good. All good.
The load the threads can hold is based on the engagement of the two threaded portions. Nominal hole size and sharp tap will give a 70% thread engagement, if viewed in cross-section. With banged up threads, threads re-formed by chasing, or oversize drilled hole, the cross-sectional area of the threads is decreased, and the load it can hold goes down. Additionally, the re-formed, chased thread is going to be cold worked a couple of more times making it brittle and cracked.
A tap ran thru a bad thread will remove material the chase may re-form. But it won't ruin good threads. Just clean them out.
A dull tap works best, if you have a drawer full.
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Highsider
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Post by Highsider on Sept 28, 2012 20:43:40 GMT -4
diameter and pitch, correct. what you did is exactly what I would have done. Using oil, run the tap thru to clean the threads, but not use much force, and stop if you start removing material. Keep going if its working fine and the bolts fit good. All good. The load the threads can hold is based on the engagement of the two threaded portions. Nominal hole size and sharp tap will give a 70% thread engagement, if viewed in cross-section. With banged up threads, threads re-formed by chasing, or oversize drilled hole, the cross-sectional area of the threads is decreased, and the load it can hold goes down. Additionally, the re-formed, chased thread is going to be cold worked a couple of more times making it brittle and cracked.l A tap ran thru a bad thread will remove material the chase may re-form. But it won't ruin good threads. Just clean them out. A dull tap works best, if you have a drawer full. Agreed 100%
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Post by C Monster on Sept 28, 2012 21:33:58 GMT -4
whats your info on the Subject and how do you clean / fix old threads whats your best and easiest way to do it Do you use tap and tie or re threader/ chaser
I was thinking it wood be a good place for some info I have use both ways well this is how it all started
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Hawkes
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Post by Hawkes on Sept 28, 2012 21:34:07 GMT -4
I do it all the time, even the opposite and run a die over the bolts. I find it rare to see newly cut threads but it does happen.
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Post by C Monster on Sept 28, 2012 21:38:01 GMT -4
from autorestoration101.com/2008/05/24/cleaning-nut-and-bolt-threads/ One of the biggest and most frustrating problems that you come across restoring an old car is stripped or damaged threads. One way that might help fix the problem is to “chase” the threads with a thread restoring tap or die. They are different than a thread cutting tap and die. A thread chaser is essentially a slightly undersized tap that will clean threads without removing any metal. Basically what they do is move the threads back into place. For years I always used a regular thread cutting die to clean up threads. Every once in a while there would be a situation where the bolt would easliy strip out after using a thread cutter on existing threads, this was because I was removing thread material and weakening the threads. I now use the thread restoring taps and dies to repair damaged threads. The thread chasers actually work very well to clean the threads of parts after they are painted. For example I use them a lot before installing a freshly painted hood. Some of the old car hoods are very heavy and to mess with getting a bolt to start with primer and paint in the holes is a pain. After chasing the threads you can easily screw the bolts in by hand. Just remember that rethreading taps and dies renew existing threads, they are not for hardened threads or for cutting new threads. I own this rethreading kit that I purchased from Snap On Tools
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Post by C Monster on Sept 28, 2012 21:39:43 GMT -4
Thanks Creepy for moving the post here for me
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Creepy
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Post by Creepy on Sept 28, 2012 22:41:25 GMT -4
[Do not use a tap or die.for fixing threads it open the threads up too much and you end up with mess up the threads A tap ran thru a bad thread will remove material the chase may re-form. But it won't ruin good threads. Just clean them out. I guess you didn't really say running a tap thru good threads will wreck them, that's what I thought I read, hence my reply that may not make sense to you. My bad. A tap is a perfect threaded form. It will cut away burrs and banged up threads. The chaser is a deburr tool, it doesn't form new threads, it cold works deformed threads back into position and makes them weaker in doing so. Chasers work great for paint and burrs, cleaning out the valleys and knocking down high spots. They will re-form threads by carrying material to where it is missing. But you are left with an imperfect thread form. This is REALLY splitting hairs...if the bolt threads in, and doesn't fall out, wobble...you are usually good. anyone who turns wrenches frequently just develops a 'feel' for stripped threads, and depending on the job the bolt is doing - it may be an issue, or it may not.
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Post by C Monster on Sept 28, 2012 22:57:49 GMT -4
Yes that was my point Running a tap thru good threads is ok ,it does not wreck them And you still have great threads. Just like new ones
But if the threads are all ready wrecked A re-threader/chaser repairs the old threads better than a tap does
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Creepy
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Post by Creepy on Sept 28, 2012 23:01:24 GMT -4
It does, yes.
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