straightening a threaded rod

[ducks13]

Sounds like I didn't get as optimal a repair as I had hoped for but it is what it is, and it works for now. The first time I adjusted it after using it a while it seemed kind of locked up, and then it turned rough and jambed, then it adjusted smoothly. It did kind of feel like maybe the helicoil could have been turning, or maybe that is just my getting nervous with what Spyderlk said. If it doesn't hold up I will have learned a little more. I should have inquired more about how they would be repairing the bend, I don't think I saw a press in the shop but I find it difficult to believe that they wouldn't have one. A shop with all thread a a welder would have worked well too. Thanks for the help guys.

 

[Soundguy]

good luck.

soundguy

 

[RoyJackson]

Sounds like I didn't get as optimal a repair as I had hoped for but it is what it is, and it works for now. The first time I adjusted it after using it a while it seemed kind of locked up, and then it turned rough and jambed, then it adjusted smoothly. It did kind of feel like maybe the helicoil could have been turning, or maybe that is just my getting nervous with what Spyderlk said. If it doesn't hold up I will have learned a little more. I should have inquired more about how they would be repairing the bend, I don't think I saw a press in the shop but I find it difficult to believe that they wouldn't have one. A shop with all thread a a welder would have worked well too. Thanks for the help guys.

As I'd written in post #8, thread clearances are pretty tight and it's quite difficult to get a good repair. There's only a few thousandths clearance between the internal (female) and external (male) thread flanks. That springback I'd written about in a previous post is probably what's causing the binding.
Main thing now is not to strip either thread, so don't force it. Might wear in over time, might not.
I have ran a die over slightly buggered threads. The die will run free over the good threads and cut the bad threads. It'll work (if you can find the right die), but the threads will be looser over the cut areas. This isn't an optimal repair and I've only used it when I couldn't replace the component. I've always considered this a temporary repair.

That adjustable link is used on the 4200, 4300, 4400, 43210, 4310 and 4410 Deeres (maybe others too). Might be something you can buy from a salvage yard, if it comes to that... BTW, there is a thread in the Private Party ads concerning a guy parting out a 4300. That might be a source.

Good luck!

 

[PoorMansCat]

When in need of a press, look for heavy pieces of equipment with hydraulics... If you have a FEL, it works great as a press. Just use something like a board to protect the threads.
If you dont have a FEL, use a jack and the weight of the tractor to your advantage.

 

[RoyJackson]

If you have a FEL, it works great as a press. Just use something like a board to protect the threads.

Boy, you can control your loader a he11 of a lot better then I can!!

 

[Soundguy]

i have used a big bottle jack and a chain to bend metal before.. especially ford radius rods..


soundguy

 

[PoorMansCat]

Boy, you can control your loader a he11 of a lot better then I can!!

what can I say... I got skills!!!!.. hahahahaha... just kiddin...

 

[RoyJackson]

i have used a big bottle jack and a chain to bend metal before.. especially ford radius rods..


soundguy

Bending or straightening metal isn't tough...as long as you don't cold work it too much. Threads...different story.

 

[Soundguy]

yep.. the thread root is what the problem is..

soundguy

 

[RoyJackson]

yep.. the thread root is what the problem is..

soundguy

Dunno, I think it's the flanks...
Got a Machinery Handbook, Soundguy? Take a gander at the thread geometry and visualize how it would bend...and the effect of the bend with the mating part.

 

[Soundguy]

i'm not refering to the fact you have a bent rod going into a straight coupler ( nut ).. i'm refering to a bent threaded rod that is going to break at the thread root once stressed more.

getting it perfectly straight is virtually impossible, thus one would expect difficulty in screwing it in / unscrewing. that why I said i never straighten threaded rod.. I only transplant or replace.

curved rod into straight hole was kindergarten stuff.. like square peg in round hole... ust don't fit..

soundguy

ps.. yes.. i do have an engineers black book.. but as said.. we are talking about 2 different problems. i'm still on the 'it's weaker now and may break again' bandwagon.. not the ' gee.. it's bent and won't screw in easilly' deal.. which was to be 100% expected by all involved.. or should have been..

 

[SPYDERLK]

:thumbsup: Yeah. Im guessing your bend was not severe? - lo straightening risk. Do you know what happened to make it bend? Im asking because if it bent from compressive force [buckling] it would be termed more a failure since this is a normal function called upon in use. If it bent from accidental side force I would call it damage. Id rather be fixing the accident, but upgrading the failure. See what I mean?

I will always use heat when straightening any non trivial threaded part that is bent enuf to impede a nut. The reason is notch strain. Virtually all bending movement takes place in the very small area at the bottoms of the threads - an extremely intense situation when you think about it. Heat eases the abuse by softening things up a bit. The harmless limit is around 600F. This is where shiny steel colors blue/purple. A straw-brown color precedes this, occuring around 400F. Any heat helps. The colder the metal the more difficult and abusive bending is. Threads/notches are just a worst case.
larry

i'm not refering to the fact you have a bent rod going into a straight coupler ( nut ).. i'm refering to a bent threaded rod that is going to break at the thread root once stressed more.

getting it perfectly straight is virtually impossible, thus one would expect difficulty in screwing it in / unscrewing. that why I said i never straighten threaded rod.. I only transplant or replace.

curved rod into straight hole was kindergarten stuff.. like square peg in round hole... ust don't fit..

soundguy

ps.. yes.. i do have an engineers black book.. but as said.. we are talking about 2 different problems. i'm still on the 'it's weaker now and may break again' bandwagon.. not the ' gee.. it's bent and won't screw in easilly' deal.. which was to be 100% expected by all involved.. or should have been..

Si'. ... This kinda stuff is absolutely critical and gets lost in the posts that dont recognize deeper relevances. That seems to be why it must be repeatedly referred to.:confused3:
larry

 

[RoyJackson]

i'm not refering to the fact you have a bent rod going into a straight coupler ( nut ).. i'm refering to a bent threaded rod that is going to break at the thread root once stressed more.

getting it perfectly straight is virtually impossible, thus one would expect difficulty in screwing it in / unscrewing. that why I said i never straighten threaded rod.. I only transplant or replace.

curved rod into straight hole was kindergarten stuff.. like square peg in round hole... ust don't fit..

soundguy

ps.. yes.. i do have an engineers black book.. but as said.. we are talking about 2 different problems. i'm still on the 'it's weaker now and may break again' bandwagon.. not the ' gee.. it's bent and won't screw in easilly' deal.. which was to be 100% expected by all involved.. or should have been..

As far as weaker...depends on how acute the bend is. If a mild bend, might not fail, but it may still bind when threading the mating part but last for quite a while. Probably a moot point though as my guess is Ducks13 will replace the adjustment link.

 

[Soundguy]

I would at least have one, or the parts on the shelf to do so. I've just had no luck straightening them.. have had 100% luck repairing them vie replacement parts.. IE.. new thread and ends / welding..e tc.

soundguy