Heim joint question

[simplysigns]

I am adding cross over steering to my 78 Blazer. I have the steering arms on and know I need to make the tierod (rod that connects the two steering arms together) and the draglink (rod that connects the pitman arm to the steering arm). I want to make these out of solid round stock metal and tap the ends. But I am not sure what size heim joint to use. Can anyone help?

Plus.....Can all the end be right handed threads??

 

[Masiony]

to answer, you probably dont want to use solid. believe it or not, tube resists bending more that solid does, because of the increase in surface area that must be bent. i am not explaining it very well, but it is true. also, i would recomend against using heims in steering, because heims are designed to be double shear. when you use a heim in single shear, such as running a bolt through the heim into the steering arm, there is just the clamping force that the head of the bolt (again surface area) can produce. this tends to lead to the bolt getting loose, and ruining your heim and the steering arm. TRE's work much better because they have a much greater surface area that contacts the steering arm (due to the taper). and TRE's are designed to run single shear. now i am not saying that people do not run heims, but i would not recomend it for a street driven truck. but if you do, get at least a 3/4" or better.

and about running all right hand thread, that is what i would do. cheaper and less spares you need to worry about.

 

[Hogback Fabrication]

to answer, you probably dont want to use solid. believe it or not, tube resists bending more that solid does, because of the increase in surface area that must be bent. i am not explaining it very well, but it is true. also, i would recomend against using heims in steering, because heims are designed to be double shear. when you use a heim in single shear, such as running a bolt through the heim into the steering arm, there is just the clamping force that the head of the bolt (again surface area) can produce. this tends to lead to the bolt getting loose, and ruining your heim and the steering arm. TRE's work much better because they have a much greater surface area that contacts the steering arm (due to the taper). and TRE's are designed to run single shear. now i am not saying that people do not run heims, but i would not recomend it for a street driven truck. but if you do, get at least a 3/4" or better.

and about running all right hand thread, that is what i would do. cheaper and less spares you need to worry about.

What Masiony said about heims is correct. They are not meant to be used in single shear. If you drill out your knuckle to a standard hole instead of tapered you will destroy the knuckle in short order.

What Masiony said about solid stock is wrong. Solid stock will be stronger in bending and denting than any tube of the same size. Think about it, take a piece of tubing and then fill it with steel and explain to me how that makes it weaker

The deal is that large diameter tubing is harder to bend. 1" solid stock and 2 1/2" .120" wall tubing may weigh the same amount, but the 2 1/2" tubing will be MUCH harder to bend and will be easier to dent (I just made up the numbers to make a point).

For things that won't see rocks (i.e. dents), larger diameter and thinner walls are the ticket. For things that will get hit by rocks, you want a smaller diameter and thicker wall to resist denting (once the tube dents its pretty much worthless).

Solid round steel is not really used on 4x4's and for good reason. Once you reach a thickness of ~.25" steel is really hard to dent.

 

[muddermilitia]

What Masiony said about heims is correct. They are not meant to be used in single shear. If you drill out your knuckle to a standard hole instead of tapered you will destroy the knuckle in short order.

What if you drilled out the knuckle but also added a double shear?

 

[gmc4cw]

What if you drilled out the knuckle but also added a double shear?

that would be a lot of fabrication when you could just use TRE's. You can buy a tie rod end at any parts store. blow up a heim joint in the middle of the woods and you could be really stuck.

somethings are worth making and others are worth buying. whats your time worth. How much does a heim cost compared to a TRE? there are several vendors who sell crossover setups that you can bolt on and go.

 

[Hogback Fabrication]

What if you drilled out the knuckle but also added a double shear?

I'm not sure if you know what double shear is. There is really no way to have double shear using a stock knuckle.

Here is what a double shear steering arm looks like:

This is the ONLY way anyone should ever mount SRE's (heims).
Single shear will wear out the hole the bolt goes through very rapidly, it puts tons of extra stress (torque) on the knuckle and makes the bolt easier to shear.

 

[ntsqd]

snip.....
What Masiony said about solid stock is wrong. Solid stock will be stronger in bending and denting than any tube of the same size. Think about it, take a piece of tubing and then fill it with steel and explain to me how that makes it weaker

Not wrong, just not complete. The middle third of solid bar is wasted weight. It does little for bending strength, but adds significant weight. Calc the bending strength of 1.5" solid bar and then the bending strength of .500" walled 1.5" tube and you'll see what I mean.

The deal is that large diameter tubing is harder to bend. 1" solid stock and 2 1/2" .120" wall tubing may weigh the same amount, but the 2 1/2" tubing will be MUCH harder to bend and will be easier to dent (I just made up the numbers to make a point).

Concur with that. Can supply an Excel spreadsheet that proves this and equivalent weights can easily be found.

For things that won't see rocks (i.e. dents), larger diameter and thinner walls are the ticket. For things that will get hit by rocks, you want a smaller diameter and thicker wall to resist denting (once the tube dents its pretty much worthless).

I'd say keep the OD as large as will work and chose the appropriate wall thickness.

BTW, that double shear arm has a significant design defect that will eventually break off one of the ears. May be fine in the service life of the part, but it's still wrong.

 

[Hogback Fabrication]

BTW, that double shear arm has a significant design defect that will eventually break off one of the ears. May be fine in the service life of the part, but it's still wrong.

Not my steering arm, but you could be right.

 

[ntsqd]

Didn't think it was. Nearly everyone does it that way & it bugs me. One more small part & a little extra care & the whole problem goes away.

 

[muddermilitia]

I'm not sure if you know what double shear is. There is really no way to have double shear using a stock knuckle.

Here is what a double shear steering arm looks like:

This is the ONLY way anyone should ever mount SRE's (heims).
Single shear will wear out the hole the bolt goes through very rapidly, it puts tons of extra stress (torque) on the knuckle and makes the bolt easier to shear.

I was thinking of the heim on top of knuckle then a plate on top of that with a gusset. Then the bolt would go through the plate, heim, knuckle. The tie-rod setup Im thinking of going with is from bulletproofsteering.com, they use F-911 bolts for their heims. not grade 8.

 

[ntsqd]

I was thinking of the heim on top of knuckle then a plate on top of that with a gusset. Then the bolt would go through the plate, heim, knuckle. The tie-rod setup Im thinking of going with is from bulletproofsteering.com, they use F-911 bolts for their heims. not grade 8.

The problem with the plate idea is that it has no real strength in a direction perpendicular to the arm. I've seen several done that way & I applaud the effort but it hasn't done much for them. There needs to be structural geometry on top and bottom, like the arm shown, to resist any intent of twisting under load. Both sides have to be equally strong at resisting a load or the bolt will be put in a bending situation.

Add in that SRE's aren't sealed against junk, and what junk can get in them can't be flushed out by greasing them like with a TRE. (Don't even consider those SRE's w/ zerks.) SRE's have a romance attached to them from race cars, but any serious racer has a regular inspection & replacement schedule. Off roaders, as a group, tend to only replace things when they start to show wear. When an SRE shows wear it is already dangerous.

The F911's are a good call.

 

[muddermilitia]

ok how about plating the sides as well? The stage II sres that im looking at are supposed to be very tight fitting to resist dirt and debris from ruining them

 

[gmc4cw]

ok how about plating the sides as well? The stage II sres that I'm looking at are supposed to be very tight fitting to resist dirt and debris from ruining them

your are making a truly valiant effort to justify the use of heims. TRE's are so easy. everyone runs them and suggests them because they work. Did you already drill out your arms?

 

[muddermilitia]

your are making a truly valiant effort to justify the use of heims. TRE's are so easy. everyone runs them and suggests them because they work. Did you already drill out your arms?

haha no i havnt even touched them yet