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Hi all.
I was wondering how to straiten a bent key rod.(lower stack)
thanks
 

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Hi all.
I was wondering how to straiten a bent key rod.(lower stack)
thanks
I have taught many people to straighten hinge screws/ stack rods/ arbors. It is really easy to do, but if you are one of those people that use a screwdriver as a hammer and a hammer as a screw driver, or are asking the question " what's a screw driver" you may want to take JBTSax's advice and take it to a tech. You run the potential risk of destroying the screw if it is done wrong or possibly whipping the long hinge rod around and smacking your body with it. It is a technique that is probably best seen and not described, but here goes........

You will need: A bent screw, piece of wood ( hammer handle, wood block, dowel...), bench motor ( or hand drill, lathe, drill press or other spinny device) drill bit slightly larger than the bent screw.

1- cross drill a hole in the block of wood. Many repair techs use one of their hammer handles for this but you can use what ever is handy.

2- By hand, bend the screw so that it is relatively straight. Slight bends are OK, but you don't want to be trying this with a drastic bend in the rod.

3- Chuck one end of the rod in your bench motor or other spinny device. Slip the wood block with the hole in it over the screw.Hold the other end of the rod with one hand so that it will slip through your fingers and still be able to spin. Hold the wood block with the other hand close to the chuck of your spinny device
4- As the rod is spinning (spinning slowly). Pull the wood block to the end of the rod. It is kind of a twisting and pulling action.
5- Repeat as needed and the rod will gradually straighten. Once the rod is straight, reverse the rod in the chuck and do the same things again.

Some things NOT to do:
Do Not spin the rod fast until you figure out the technique.
Do not attempt a rod with a sharp kink in it until you know what you are doing
Do not grip the rod by the threads of the screw in the chuck of your spinny device
Do not try to strighten flute or oboe rods that have cross drilled pin or screw holes...untill yo know what you are doing.
Do not stick your face close to the spinny device because you may get whipped in the face by a hinge rod if you do it wrong.
Do not try to do this if you don't have a bench motor with a foot switch or a friend that can turn off the spinny devices in an instant, of if you don't have three hands.

In all seriousness, it is a fairly easy technique, but if you are not mechanically inclided leave it to someone else.

As far as cost goes, If you brought me the rod I probably wouldn't charge you to straighten it, unless it was kinked with a pretty sharp bend.

Matt
 

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With all due respect Matt, in spite of your excellent description, straightening a rod is best taught by an experienced mentor in a hands on session, not by reading instructions on a discussion forum. It is human nature to read the warnings and charge ahead thinking, "that couldn't happen to me".
 

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straightening a rod is best taught by an experienced mentor in a hands on session, not by reading instructions on a discussion forum.
I learned by reading about it in a book and then practice. If I had to learn it from someone actually showing me how to do it, I would never learn it since there is no one to show me. Same for many other things in woodwind repairs. But yeah, if someone is trying this or anything else that could be risky, be very careful and consider that something might happen.

BTW since he said "lower stack" I guess it's obvious he is talking about a rod screw. A "key rod" could also mean the hinge rod, not the screw, which is very different (can see sticky about terms). For longer bent rod screws it helps to gradually chuck it in different spots and repeat, to make the lever (e.g. wood with hole) closer to the place the rod is held, which is not possible without a through hole (if you can straighten it half way then reversing will work or might not be too difficult).
 

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Like any other repair technique, the chances of success with the drill method improve with practice.
The easiest way to achieve this is to get an old wire coat-hanger and cut off a few lengths to use as practice rods. It's worth taking the time to file and smooth off the cut ends - just in case one whips and catches your hands...and I would recommend wearing safety goggles.

I would add to the list of things not to do - don't stop the process halfway through...once the rod is spinning and you've started to move the wood down the length of it, don't stop until you reach the end.

Regards,
 

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An important "Do Not" was omitted.

Do not bend the rod in such a way that there is bending force adjacent to the chuck. At best, you are likely get severe dents in the surface of the rod from the chuck jaws. At worst, the rod will break at this point.
 

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Well written matt, Im one of the ones that has mulitple sized drill holes in my hammer handles, I tap the rods down on an anvil if really bad and then spin as per your process, and if that doesnt work just make a new one which is sometimes even quicker
 

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With all due respect Matt, in spite of your excellent description, straightening a rod is best taught by an experienced mentor in a hands on session, not by reading instructions on a discussion forum. It is human nature to read the warnings and charge ahead thinking, "that couldn't happen to me".
I gave due respect to your warning and I agree that some people don't know one end of a tool from another and could mess this up easily and possibly get hurt. Not everyone is like that. With that said, if I went by your warning for everything I've learned to do that I either tried on my own or only read about to learn. I wouldn't know how to do 90% of the things I know now.
Matt
 

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But a side story if I may

When I was in the military many moons ago we had a gentleman that was a general hand, this is a person that is like a basic labourer, they do the odd jobs around the hangar. The position is usually filled by people that fail of an apprentice cource for mechanics or avionics etc, so instead of booting them out ofd the military they were given the option to have a job but as a general dogs body

Now I kid you not here.........Our general hand was asked to put some brackets on one of tha main concrete hangar walls for supporting a shelf for a stereo system, he asked the boss what do I use, he was told to use a hammer drill. He attempted to put a hole in the wall by placing the drill against the wall and used the hammer to actually ""HAMMER"" the back of it...I kid you not
 

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This might be a good opportunity to also discuss straightening smaller rods such as those often encountered on clarinets etc. I usually use a bench anvil and a rawhide mallet but I'm open to better methods.
 

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But a side story if I may

When I was in the military many moons ago we had a gentleman that was a general hand, this is a person that is like a basic labourer, they do the odd jobs around the hangar. The position is usually filled by people that fail of an apprentice cource for mechanics or avionics etc, so instead of booting them out ofd the military they were given the option to have a job but as a general dogs body

Now I kid you not here.........Our general hand was asked to put some brackets on one of tha main concrete hangar walls for supporting a shelf for a stereo system, he asked the boss what do I use, he was told to use a hammer drill. He attempted to put a hole in the wall by placing the drill against the wall and used the hammer to actually ""HAMMER"" the back of it...I kid you not
As a young bloke, i worked a casual, weekend job as leading hand in a supermarket. One of the fellas dropped a pallet of cooking oil on the loading dock. I told him to start cleaning it up and went to grab a few dozen bags of salt and a shovel. When i came back, he had a bucket of hot water and a mop and had managed to spread the lot all over the loading dock. Ya live and learn.
 

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I gave due respect to your warning and I agree that some people don't know one end of a tool from another and could mess this up easily and possibly get hurt. Not everyone is like that. With that said, if I went by your warning for everything I've learned to do that I either tried on my own or only read about to learn. I wouldn't know how to do 90% of the things I know now.
Matt
There are not many people who can match your high level of ability and skill in machining and mechanics. I mean that as a sincere compliment. When passing on information on a public forum, none of us have any control over who will try to use that information and what their level of ability might be.

Remember the OP probably has only 1 hinge rod to practice his "never done this before or even saw it done" trial and error on. Also when there is a bent rod, there is also a strong possiblity that there is a bent hinge tube as well---not to mention misaligned posts and possibly body damage.

One of the first rules one learns as a teacher is, "Just because it was easy for me to learn to do something doesn't mean it will be easy for the student".
 

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Thats very debateable, I really think you must believe people that work in offices and paperwork jobs are very incapabale. Most people john have hobbies, be that making things out of wood like tables chairs furniture in general, or building model planes boats, or fitting a book shelf in there house. Just becuase they are not a repairer in some peoples views or terms does not mean there incapable of turning a drill on and running a block of wood up and down the rod..

To be honest I think some repairers are very incapable of the basics themselves, yet they still call themselves repairers...

I think out of every 500 people there might be one that may not have the skill base to attempt it. but that doesnt mean the other 499 cannot do it or are incapable with some basic instruction even if that instruction is written
 

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This might be a good opportunity to also discuss straightening smaller rods such as those often encountered on clarinets etc. I usually use a bench anvil and a rawhide mallet but I'm open to better methods.
You're gonna love this then!

Mount the screw in the lathe/drill with the thread protected inside the jaws, then get a length of brass tube - an old saxophone key barrel is ideal as long as it's not too loose a fit (nor too tight that it can't go over the bend).
Pop it over the screw, fire up the lathe/drill, angle the tube in the same way as you would a hammer handle on a long rod and slowly withdraw.

A couple of notes: It seldom works if the thread is on the exposed end as it will catch in the tube, and a minute or so spent ensuring that the slotted end is smooth will pay dividends.
Don't be too alarmed at how much the tube jumps around at first - keep a firm grip and be bold!

If you've never used the technique before it's as well to practise it on a few old rod screws. You'll soon learn to gauge the most effective size of tube to use.

Regards,
 

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Glad you liked it.
You can adapt the technique as you see fit - for example, you might find using collets will allow you to get more length on the screw.
You could also try different materials for the tube. Brass seems to work best, but Delrin does ok (for a while, at least until it wears) and isn't so likely to mark the screw.

Regards,
 
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