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HS-411 Bolts Stipped ARG*

nippaero

nippaero

Well Known Member
HS-411 Bolts Stripped ARG*

Well to make a long story short. I bought a cheap POS torque wrench from Harbor Freight. I might as well have flushed the money down the toilet. It doesn't work and I stripped two AN3 bolts that go through HS-411 to the HS-603 spar. One nut backed off fine but the other one wont back off. I tried using a vise grip and pulling the nut as I turned it. Does anyone have any ideas how I can back this sucker off?

http://picasaweb.google.com/mikenip...photo?authkey=HheSY7sq2EY#5090024900921937698

BTW. I returned the torque wrench and bought one from sears that works like a champ. I had to order some extra bolts from Van's.
 
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Torque

Sounds like the chinese that make Harbor Freight **** use the Redneck torque scale which is: Red Torque or Blue Torque.

Translation: Small bolt, torque tilll yer red in the face.
Large bolt, torque till yer blue in the face.

All I ever knew till I joined the Service.

Seriously, look around for a nut splitter. They fit around the nut and have a chisel type point that is screwed down so that the chisel physically splits the nut which you then can remove. Hopefully you can find one that is small enough to fit an AN-3 nut.
 
nippaero said:
Well to make a long story short. I bought a cheap POS torque wrench from Harbor Freight. I might as well have flushed the money down the toilet. It doesn't work and I stripped two AN3 bolts that go through HS-411 to the HS-603 spar. One nut backed off fine but the other one wont back off. I tried using a vise grip and pulling the nut as I turned it. Does anyone have any ideas how I can back this sucker off?

http://picasaweb.google.com/mikenipp/EmpennageHorizontalElevator/photo?authkey=HheSY7sq2EY#5090024900921937698

BTW. I returned the torque wrench and bought one from sears that works like a champ. I had to order some extra bolts from Van's.
Click to expand...
Just take your trusty dremel and a cutoff wheel and lop off the entire bolt. You wouldn't want to re-use either part
-mike
 
I agree with Mike. Place 2 cutoff wheels together and grind off the bolt head. Double cutoff wheels last MUCH longer during this type of operation. Be VERY careful not to damage the material around the bolt head.
 
Mike, If you don't have a dremel tool, you need to get one. After one use, you will ask yourself how you have lived without one.

The POS cutoff wheels that come with them need to be thrown in the trash can though. They are dangerous. The least little hint of a side load and the wheel will disintegrate while at a bazillion RPM. They do sell a heavy duty fiber cutoff wheel with a quick change arbor. It will cut through that bolt in nothing flat.


This is the good one:
http://www.dremel.com/en-us/attachments-and-accessories/attachment-accessory-detail.htm?H=188549&G=69875&I=69877
 
And a few layers of protective masking tape around other areas than the bolt is a good idea too. Just in case the cutoff wheel slips! :eek:

L.Adamson
 
Thanks for the suggestions. I will shop around for a dremel tool. It may come in handy down the road too.
 
Dremel makes a ScotchBrite wheel for the tool. It is item #500. I have gone thru 2 of them just with the empennage. It can get into places other deburring tools can't.
 
Ok, I figured the book said between 1.6 to 2.0 foot lbs of torque. Is that right? I bought a torque wrench from craftsman for $70 and set it at 2 lb. Turned the nuts and they didn't seem to be getting tighter. I stopped because something didn't seem right. Went a little further on the one and twisted it right off. 2 Lb? What gives? Thought the torque wrench didn't work so I put it on some metal bolts and it clicked where I thought 2 lb's should be. Are those bolts really that weak? I couldn't believe it but it happened. The other ones I just snugged up and a little more. Don't want to twist them off also. Do I now need to get the bolt from van's or where else can I get them?
 
OK....easy to break 'em

The AN3 bolts are in INCH-POUNDS...Can't remember how many but not many of them at all!

My 1/4" INCH-POUND torque wrench from Harbor freight works very well.

You cannot set 2 foot pounds of torque on a wrench thats good for say 75 foot pounds as its way too coarse to get a proper adjustment.

The click will be almost un perceptable (that can't be a word) even with the 1/4" torque wrench. I bet it had already clicked and you kept tightening way beyond that point.

Just a guess.

Frank
 
ditch said:
Ok, I figured the book said between 1.6 to 2.0 foot lbs of torque. Is that right? I bought a torque wrench from craftsman for $70 and set it at 2 lb. Turned the nuts and they didn't seem to be getting tighter. I stopped because something didn't seem right. Went a little further on the one and twisted it right off. 2 Lb? What gives? Thought the torque wrench didn't work so I put it on some metal bolts and it clicked where I thought 2 lb's should be. Are those bolts really that weak? I couldn't believe it but it happened. The other ones I just snugged up and a little more. Don't want to twist them off also. Do I now need to get the bolt from van's or where else can I get them?
Click to expand...
What is the max value on this torque wrench? Torque wrenches aren't very accurate if you are running close to the lower end of its capability. Ideally, you really should have a wrench with a low enough max value so you are working at torques at least 20% of the max value.

You can purchase replacement bolts at any place that sell aircraft bolts - Van's, Aircraft Spruce, Wicks, etc. I'd replace any bolts or nuts that you have torqued with that torque wrench. The cost of the replacement hardware will be much cheaper than the cost of the accident that could occur if the over-torqued hardware fails in service.
 
Low end of reange?

ditch said:
Ok, I figured the book said between 1.6 to 2.0 foot lbs of torque. Is that right? I bought a torque wrench from craftsman for $70 and set it at 2 lb. Turned the nuts and they didn't seem to be getting tighter. I stopped because something didn't seem right. Went a little further on the one and twisted it right off. 2 Lb? What gives? Thought the torque wrench didn't work so I put it on some metal bolts and it clicked where I thought 2 lb's should be. Are those bolts really that weak? I couldn't believe it but it happened. The other ones I just snugged up and a little more. Don't want to twist them off also. Do I now need to get the bolt from van's or where else can I get them?
Click to expand...

The ANSI specifications for torque wrenches usually don't even recommend use of the torques wrench for values under 20% of the full scale...

What is the maximum value on the scale for your Craftsman wrench? Perhaps you are operating it way too close to zero?

Lots of info in this thread, started off with the exact same problem...

http://www.vansairforce.com/community/showthread.php?t=16185&highlight=torque+wrench
 
Ya, my wrench has a max of 75 ft lbs. The thing is, when I put it on a regular bolt, it clicked when I thought it would. Oh well, I guess I may as well replace all of them as long as I have to replace one.
 
Seen it before.

This has been covered before, but it still seems to happen pretty often. If you have never used a torque wrench before, then I would suggest that you practice with several sizes of nuts and bolts before you start cranking on the bolts in your kit. Apparently, it does not take that much to twist the heads off of an AN-3 bolt, since it seems to happen every 3-6 months or so.

I have the Harbor Freight 1/4" and 3/8" torque wrenches, and both work ok. However, when torqing the AN-3 bolts to 25 in-lb, the break is very light, and there is no perceptible audio click that you might be used to. 25 in-lb is probably less torque than what I can put on using a screw driver style nut driver.

BTW, 24 in-lb is the same as 2 ft-lb. However, if you are using a wrench calibrated in ft-lb, then it's probably not a good idea to use it on AN-3 bolts (unless it is a 0-10 ft-lb wrench with .1 ft-lb increments). You really should be using an in-lb wrench on AN3 bolts.

BTW, I learned my lesson about twisting the heads off of bolts at the, relatively, early age of 12, when I twisted the head off of one of the head bolts on my father's 53 Ford pickup. That was the same day that I learned hou to remove a bolt that had the head twisted off. We all have to learn sometime.

Cheers,
Tracy.
 
Mike - I follow your build pretty closely - you're only a few steps ahead of me. Good luck. I would say use a die grinder or a pencil grinder to cut the bolts or nuts off. People have recommended a dremel, but I prefer an air pencil grinder, and found a great deal on a Sioux pencil grinder on eBay - if you're interested I can put you in touch with the seller.
 
You dont need to torque 90% of the bolts in your project, none in the empenage. All of the bolts are in shear, however, those that feel that you must torque, will call them "the torkers", are always using the torque values for tension, which is what the standard 365 nuts are, tension nuts. They are just being used in shear applications. Basically, the range of acceptable torque is huge, somewhere between Shear, and Tension and then the extra 100% or so on top of that before you have deformation. Confused yet? If you stripped it, you really reefed on it.
When I got into this debate last time, I asked several very experienced builders and the answer was unanimous; Torque wrenches do more harm than good on the bulk of your fasteners due to misapplication of the tool. One of Vans people just laughed when I asked him about torquing AN3s. Does anybody really do that? (he built and flies his own, untorqed machine)
Use the appropriate sized wrench, your own mechanical inclination, and tighten those AN3's by hand.
Now, before I get flamed, I did torque my An3s in my center section. I did torque them for tension, even thought they are in shear, 'cause the nut is a tension nut and can take it. And I did torque all other "critical" fasteners, engine mount, spar bolts, etc...
If you must torque your AN3's, make sure you get the feel of it. Even a torque wrench for inch pounds has a big lever on it.
Ok - I'm done. Resting now. So, flame away all of you "Torkers". ;)
 
Yep... people, buy a normal 1/4" drive ratchet, ANYTHING under AN5 bolts should be torqued with that. It's not hard to over torque a AN3 with that, but it's REALLY hard to break one with a standard length 1/4" drive. Just get that and tighten it to a confortable torque. Don't bother torqueing this stuff, you won't be able to do it accurately without 4 different torque wrenches. Most A&P's i know torque only critical things that the book says specifically to, like spark plugs.

What you just tighten spark plugs? Sighhhhhhh.
 
At last

Somebody that admits he never used a torque wrench on the entire airplane....well not quite but I also admit that I only used them on large critical fasteners to make sure I had enough torque on them.

A bolt will never fail in service if it has been "overtorqued" at installation...But a bolt in tension (which I doubt if any of ours are) could fail if they wern't tight enough.

Cheers

Frank 7a
 
frankh said:
A bolt will never fail in service if it has been "overtorqued" at installation...But a bolt in tension (which I doubt if any of ours are) could fail if they wern't tight enough.

Cheers

Frank 7a
Click to expand...
I'm afraid I'm going to have to disagree here. A bolt that has been over torqued may very well be stretched or twisted. The stretching or twisting will occur at the base of the threads. This weakens the bolt considerably and it CAN fail, even in shear.
NEVER reuse a bolt that has been over torqued.
 
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frankh said:
A bolt will never fail in service if it has been "overtorqued" at installation...But a bolt in tension (which I doubt if any of ours are) could fail if they wern't tight enough.
Click to expand...
I have a hard time understanding why this should be true. Is this statement based on some evidence?

I wouldn't want to test this theory in an application where a bolt failure could lead to a fatal accident, i.e. in an aircraft. It really isn't very much trouble to properly torque bolts, and this is one of the many wrong places to cut corners.
 
Granted, MOST of our bolts are in shear, but some of the important ones are in tension, like engine mount bolts and prop bolts. These are pretty important.
 
It is true

Kevin Horton said:
I have a hard time understanding why this should be true. Is this statement based on some evidence?

I wouldn't want to test this theory in an application where a bolt failure could lead to a fatal accident, i.e. in an aircraft. It really isn't very much trouble to properly torque bolts, and this is one of the many wrong places to cut corners.
Click to expand...

Its a well known fact....If the tension in a fastener is more than the cyclic load placed on the parts in service, the tension in the fastener does not change...If the loads in service exceed those placed on the fastener when it was torqued then the tension in the fastener will vary with the service load...which can lead to fatigue failure.

This is why a cylinder head bolt/stud will only ever break if not enough tension was plced into it when it was first torqued.

This is why you certainly would not want to UNDER torque a prop flaange bolt but a few pounds over is on the safe side...as long as the clamping force does not damage the componens its clamping of course.

You can tighten a bolt up to the point of yeild in a fastener...(Would I do this on an airplane?..NO..). have you noticed how many new cars have cylinder head bolts that can only be used once?...Its because they are tightened until they just start to yeild...I.e they are permanently stretched.

Frank
 
Let me clarify

Mel said:
I'm afraid I'm going to have to disagree here. A bolt that has been over torqued may very well be stretched or twisted. The stretching or twisting will occur at the base of the threads. This weakens the bolt considerably and it CAN fail, even in shear.
NEVER reuse a bolt that has been over torqued.
Click to expand...

You are correct Mel (and I should have clarified this point)but what you are talking about is a fastener that has been torqued so much that it has reached it yeild point...What I am talking about is a fastener that is a little bit over torqued, i.e a fastener that is still in its ELASTIC range.

The problem with a tiny fastener like an AN3 is that (especially with a clumsy big TR) its hard to know where it has been tightened to...If you tighten the fastener by hand you can feel if it gives and you should have enough experience to know how much oomph you putting into the wrench.

My point is that for small fasteners s long as you don't feel the "give" (i.e plastic deformation....i.e stretched) then you really don't need an accurate torque setting....As long as you don't UNDER torque them....:)

Frank
 
Frank,
Your point is well taken. I have been a mechanic for over 50 years and can "feel" proper torque on small bolts. MY point, however, is that the majority of guys on this forum don't have our experience and should NEVER re use a bolt that has been over torqued. Especially something on the order of an AN-3 bolt where even minor over torquing can destroy the integrity of the bolt.
 
Learn to use the tools.

JonJay said:
... When I got into this debate last time, I asked several very experienced builders and the answer was unanimous; Torque wrenches do more harm than good on the bulk of your fasteners due to misapplication of the tool. One of Vans people just laughed when I asked him about torquing AN3s. Does anybody really do that? (he built and flies his own, untorqed machine)
Use the appropriate sized wrench, your own mechanical inclination, and tighten those AN3's by hand. ...
If you must torque your AN3's, make sure you get the feel of it. Even a torque wrench for inch pounds has a big lever on it.
Click to expand...
Jon,

I don't really want to flame you, but I have a problem advising someone who cannot work a torque wrench correctly to "tighten those AN3's by hand". If they do not have the correct "feel" to set the proper torque using a torque wrench, then it is unlikely that they have the experience to properly "feel" the correct torque without a torque wrench.

Guys, learning to use the tools properly is part of the educational part of building an airplane. If you cannot use the tools properly, then get some help, or practice until you can. Not using a torque wrench on a nut or bolt because you cannot get the torque wrench to work properly is not acceptable. Not using a torque wrench on a nut because you "know" what the proper torque should feel like is only acceptable if you have a "calibrated wrist". It's not that hard to develope a "calibrated wrist", but if you cannot operate a torque wrench, it is hard to check the calibration.

So, did I use a torque wrench on the AN3 bolts that I have installed so far? A few, just to check the calibration--close enough.

Cheers,
Tracy.
 
Matt,
Glad to hear you are pretty close behind me. Shoot me the info on the Sioux pencil grinder. I'll take a look at it. I did score a great deal on a Dremel the other night. Home Depot had the 300 series on sale for $29. That is a good price on those things.

BTW. The wrench I got from sears is in in/lbs and it seams to be working great. The break on the head is very slight so you have to watch carefully. No click as in higher settings. I think the torque wrench from HF was completely bad. I couldn't even get it to flex when I put it in a vise. My bad for now checking before I went straight to my spar with it!! As a new builder, I am going to torque when the manual says to for now. I don't have the "feel " down yet.
 
thallock said:
Jon,

I don't really want to flame you, but I have a problem advising someone who cannot work a torque wrench correctly to "tighten those AN3's by hand". If they do not have the correct "feel" to set the proper torque using a torque wrench, then it is unlikely that they have the experience to properly "feel" the correct torque without a torque wrench.

Guys, learning to use the tools properly is part of the educational part of building an airplane. If you cannot use the tools properly, then get some help, or practice until you can. Not using a torque wrench on a nut or bolt because you cannot get the torque wrench to work properly is not acceptable. Not using a torque wrench on a nut because you "know" what the proper torque should feel like is only acceptable if you have a "calibrated wrist". It's not that hard to develope a "calibrated wrist", but if you cannot operate a torque wrench, it is hard to check the calibration.

So, did I use a torque wrench on the AN3 bolts that I have installed so far? A few, just to check the calibration--close enough.

Cheers,
Tracy.
Click to expand...

No offense taken at all, and I agree completely. It takes a certain amount of mechanical inclination. It is too bad that more builders do not have an experienced AP or Builder to assist them early in the process to develop that. I was lucky and had a 12 time builder, several Van employee hangar buddies, and lots of RV folks around to ask questions of. My BS in Inustrial Education (Shop Class) and a life time of tinkering did not hurt either.
You must learn to use a torque wrench if you are going to finish the project. There are way too many critical bolts that need to be torqued. As you suggest, find someone who can show you how to do it if you do not have the experience or mechanical inclination.
 
nippaero said:
Matt,
Glad to hear you are pretty close behind me. Shoot me the info on the Sioux pencil grinder. I'll take a look at it. I did score a great deal on a Dremel the other night. Home Depot had the 300 series on sale for $29. That is a good price on those things.

BTW. The wrench I got from sears is in in/lbs and it seams to be working great. The break on the head is very slight so you have to watch carefully. No click as in higher settings. I think the torque wrench from HF was completely bad. I couldn't even get it to flex when I put it in a vise. My bad for now checking before I went straight to my spar with it!! As a new builder, I am going to torque when the manual says to for now. I don't have the "feel " down yet.
Click to expand...

Mind telling which brand/model wrench you got? I'm in the market for one too...
 
Self Calibration...

Guys, especially new builders....

A little elementary maths can be used to get the hang of the torque needed for AN3 hardware.

Taking 20 in lbs as a reference, and noting that this is a "pull" of 1 lb on a 20 inch lever.

If our 3/8 wrench is 5 inches long, then the pull needed would be 4 lbs (20 divided by 5) --- simple ratios.

So, take an empty 1 gallon milk jug and fill it just under half full (water is about 8.33 lbs per US gallon) and tie a length of string to it.

Pull the string over the edge of a table, and this is the "pull" that you need on the end of that 5 inch wrench to get 20 in lbs on the nut.

It's amazingly low, especially for those of us used to working on cars... use a long handled wrench, and its really easy to over-torque... :(

Use a clicker-type torque wrench that is over 12 inches long, and it's way easy to over-torque if you miss the break action (just over 1 1/2 lbs pull at the end).

A simple test, and after a few tries, you should get the feel of what torque is needed for AN3 bolts without using a torque wrench.

This would be a good test for new builders.....

gil in Tucson

PS forgive the use of elementary maths... no insult intended for those who like maths... I've just noticed people either like or hate maths, and those that dislike it tend to ignore it's uses.... :)
 
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