Adjustable Thread Cutting Dies?

[thebeekeeper1]

I have to thread a tie rod to add a turnbuckle and can only find adjustable round dies. I've only used the hex-shaped Craftsman and Greenlee dies, so this is something new. I can only imagine the adjustment allows one to cut shallow threads, then progressively deeper as you tighten it down--correct?

The problem I have is a John Deere mower with a front wheel that is aimed outward a bit. Apparently the prior owner hit something going full speed and bent something beyond just the wheel spindle (already replaced). It steers fine now, but I like things "nice" so I obtained another tie rod and a turnbuckle sized appropriately (5/8"), but from a different mower brand. I have the RH thread die, but have to buy a LH and can only find the "split" or adjustable dies. I guess I will also have to add a handle that will accomodate the round die too. MSC has them for not much money, and in HSS.

I'm told the tie rod is "hard" so I'm going to attempt the RH threads and make sure it's do-able before I buy a die that will almost surely never see use again. In case you can't tell I am definitely a "weekend warrior" and definitely NOT a mechanic.

 

[Leaflessshadetree]

Wouldn't it be cheaper to just buy the correct rod and/or rod end?

 

[A_Pmech]

Split dies are designed to allow small adjustments to the pitch diameter. Once set, they should not need adjustment during the lifetime of the die. The "relaxed" size of the die ground at nominal pitch diameter.

 

[thebeekeeper1]

Wouldn't it be cheaper to just buy the correct rod and/or rod end?

There's no such thing--I have the correct rod on it, but the toe is out by a noticeable amount. JD has zero adjustment in their tie rods. They are simply a 5/8" round rod with pressed-in swivel studs at each end.

Something is bent, but it is not visible and would be expensive to replace the entire front end of the tractor. Simply by adding about 1/4" in length I can bring the wheel back in and get it pointing straight ahead.

I'll try to find a pic on Ebay. BRB.

Edit: It looks just like this one:

http://www.ebay.com/itm/Sears-Craft...781?pt=LH_DefaultDomain_0&hash=item540f3ea1e5

 

[thebeekeeper1]

Split dies are designed to allow small adjustments to the pitch diameter. Once set, they should not need adjustment during the lifetime of the die. The "relaxed" size of the die ground at nominal pitch diameter.

Ah, okay. This would be obvious to someone more knowledgeable, but how do you know when it is adjusted correctly? A nut goes on smoothly and without wobble? Pardon my ignorance--I greatly appreciate the help.

 

[A_Pmech]

Ah, okay. This would be obvious to someone more knowledgeable, but how do you know when it is adjusted correctly? A nut goes on smoothly and without wobble? Pardon my ignorance--I greatly appreciate the help.

It's adjusted correctly when the pitch diameter of the thread produced is within specification. In the machine shop, we have ways of measuring this and adjusting accordingly.

In your application, if the nut threads on it should be fine. To get a feel for the right fit, take a nut and bolt of the same size and observe how the nut behaves on the bolt's threads.

 

[thebeekeeper1]

It's adjusted correctly when the pitch diameter of the thread produced is within specification. In the machine shop, we have ways of measuring this and adjusting accordingly.

In your application, if the nut threads on it should be fine. To get a feel for the right fit, take a nut and bolt of the same size and observe how the nut behaves on the bolt's threads.

Will do, and that makes perfect sense, so THANKS!

 

[Fretters]

Start off with the centre screw tightened up in the split first, and then tighten the outer two screws. You can always back off the centre screw and tighten the die up for a second pass if it doesn't pass muster running a nut down it.

 

[kjbenner]

Split dies are designed to allow small adjustments to the pitch diameter. Once set, they should not need adjustment during the lifetime of the die. The "relaxed" size of the die ground at nominal pitch diameter.

So would you typically set a die for a particular thread class and leave it (presumably then having multiple dies on hand, one for each class you work with)?

 

[Steinmetz]

I have to thread a tie rod to add a turnbuckle and can only find adjustable round dies. I've only used the hex-shaped Craftsman and Greenlee dies, so this is something new. I can only imagine the adjustment allows one to cut shallow threads, then progressively deeper as you tighten it down--correct?

The problem I have is a John Deere mower with a front wheel that is aimed outward a bit. Apparently the prior owner hit something going full speed and bent something beyond just the wheel spindle (already replaced). It steers fine now, but I like things "nice" so I obtained another tie rod and a turnbuckle sized appropriately (5/8"), but from a different mower brand. I have the RH thread die, but have to buy a LH and can only find the "split" or adjustable dies. I guess I will also have to add a handle that will accomodate the round die too. MSC has them for not much money, and in HSS.

I'm told the tie rod is "hard" so I'm going to attempt the RH threads and make sure it's do-able before I buy a die that will almost surely never see use again. In case you can't tell I am definitely a "weekend warrior" and definitely NOT a mechanic.

There exist different classes of threads. That is why round dies are adjustable.

 

[Fcvapor05]

So would you typically set a die for a particular thread class and leave it (presumably then having multiple dies on hand, one for each class you work with)?

Yes.

If you're dealing with very tight thread tolerances you also might make minute adjustments to an adjustable die depending on the material you're cutting, since every material has slightly different springback when being cut.

 

[A_Pmech]

So would you typically set a die for a particular thread class and leave it (presumably then having multiple dies on hand, one for each class you work with)?

Solid dies are such a crude method of making external threads. In most cases, the surface finish is so poor that it's impossible to accurately gage the external thread form.

I would never make a class 3 thread with a die and the need to make a class 1 thread is extremely rare. For the most part, the only purpose of the adjustment feature in modern machining is to annoy the operator.

In theory, one can expand the die, make a roughing cut, then retract the die and make a finish cut. I still tends to make lousy threads in most steel-like materials.

 

[Fretters]

In theory, one can expand the die, make a roughing cut, then retract the die and make a finish cut. I still tends to make lousy threads in most steel-like materials.

The slight expansion ability does also make them extremely useful when chasing threads on older equipment, where it's not uncommon to find slight variations in cut/width. That's another reason I always start on full width. The amount of times I've gone to clean threads and found that on one it might spin down freely, whilst on another it's quite snug, even tight. Better to undercut than overcut.

 

[justme-]

on the other side of this issue - if you follow the logical concept of first what could have been damaged by the impact you should be able to determine what's bent fairly easily. like wise if you follow the steering mechanism from the spindle back into the machine toward the steering rack you should also find the issue fairly easily.
Just off hand (from encountering a few of these exact situations) I'd head right to the steering rack and check the rack where the tie rods attach as well as the part of the frame where the steering shaft meets is. Usually it's thin plate steel with a bushing that the shaft sits in and that can deform just as easily as the rack.
Front axle could also be bent, but should be obvious if you look for it.

 

[srmofo]

What about going to McMaster Carr and buying some rod ends that are already threaded. They're fairly cheap. I just bought some 1/2" rod ends last week for $9

 

[thebeekeeper1]

on the other side of this issue - if you follow the logical concept of first what could have been damaged by the impact you should be able to determine what's bent fairly easily. like wise if you follow the steering mechanism from the spindle back into the machine toward the steering rack you should also find the issue fairly easily.
Just off hand (from encountering a few of these exact situations) I'd head right to the steering rack and check the rack where the tie rods attach as well as the part of the frame where the steering shaft meets is. Usually it's thin plate steel with a bushing that the shaft sits in and that can deform just as easily as the rack.
Front axle could also be bent, but should be obvious if you look for it.

As you can tell, I'm no expert, nor highly skilled, but I do fuddle along and have almost graduated to "piddler" status. Here's the whole story, in case anyone is interested:

I noticed the front wheels were badly out of alignment--probably an inch or so outward on the toe. There is no adjustment, but I did notice the tie rod had a section of pipe welded into it, as though it could have been a turnbuckle, but was "farmer welded" into place. I went back to the guy I bought it from and inquired. The machine was bought "as is" but he works on them, so I wanted his advice. He said he would bet the tie rod was made from two of them, and welded up too short, which would produce the situation I had.

He gave me another tie rod, saying it would likely fix my problem. As added insurance, I stumbled across a mint pair of spindles on Ebay for cheap--$20.99 shipped to me--so I bought them too.

Turned out the cobbled up tie rod was the perfect length, so I went to work replacing the spindles. I could see the right one was bent, or appeared to be. I was happy, as this meant just four snap rings stood between me and success. Replacing them did fix about 80% of my problem, but the balance remains elusive.

With the wheels off I sighted down the back of the axle and it is perfectly straight. There just isn't anything left to check. That being the case, he suggested using my original tie rod, along with a turnbuckle he gave me from another brand of mower, to make a cobbled up, but effective, means of correcting the problem. That's where I'm at now.

He did mention the tie rods are "hard" so I'm not sure I can thread it. Because of that, I'm going to do the right hand thread first, as I already have a die for that. If successful I will then buy the LH one and finish the job. I will have a one-of, but it will work correctly. It steers fine, so if I'm unsuccessful it will just be an aggravation, but not anything affecting the use of the mower. Travelling down the road at highway speeds would eat the tire, but plodding along on sod means it's not an issue.

Thanks again to all who have helped! This forum is a hugely valuable asset for a piddler-in-training.

 

[thebeekeeper1]

What about going to McMaster Carr and buying some rod ends that are already threaded. They're fairly cheap. I just bought some 1/2" rod ends last week for $9

The ends are pressed in and not adjustable. I posted a link above showing an identical one, though it is for a different brand of mower.

 

[Fretters]

Some threaded rod, 2 rose joints and 4 nuts, (one nut either side of the rose joint to secure it in place on the rod), would be a simple way of making an adjustable track/tie rod. Standard threaded rod isn't the strongest of stuff, but it'd do for testing and probably fairly light use. You could always sleeve the rod with tube to strengthen it somewhat, else get a higher grade of rod than the standard mild.

 

[Mohawk Dave]

Just an idea...cut and weld the drag links turnbuckle and ends from a Ford Ranger in there. Then you will always have adjustment.


Weld, Grind, Paint, Voila.

 

[Givl Reggin]

The front wheels are suppose to toe-in a good inch or so - it help keep the tractor going in a straight line and return the steering wheel to center. Do you have power steering on that model? I've had the steering ram on mine bend (Cub Cadet model) and it affected toe-in because the ram was no longer centered.

 

[thebeekeeper1]

The front wheels are suppose to toe-in a good inch or so - it help keep the tractor going in a straight line and return the steering wheel to center. Do you have power steering on that model? I've had the steering ram on mine bend (Cub Cadet model) and it affected toe-in because the ram was no longer centered.

No power steering--it's an LX 176

I currently have about 3/4" of toe OUT. It's not enough to feel it in the steering, but it's noticeable, and not right. Things like that bother me.