I was adjusting some of the suspension on my 66 C10 with corvette suspension today and I was looking at the heim joints and noticed that there wasn't a whole lot of threading inside the adjuster rods. Question…. how much thread has to be screwed into the rods? Do you measure this in inches or turns of the threads? I have a friend who has a race car and he gave me some tips but I want to see what the hot rod experts have to say about it.
It is my understanding that hardware needs to be threaded in at least the same amount as the diameter of the fastener.
By fastener I assume you mean the thread of the heim? In which case, I'd make that at least into double the diameter. (ignoring the Corvette suspension part)
Yea, I was speaking about the thread, on any fastener. That being said, I always set up anything with rod ends with as much as possible being threaded in, never less than half threaded in. But that's just me, so I never have to worry about it.
Not to steal a thread but I went into a hardware store and asked the lady for a heim joint. She said " you can't talk to me like that." I said "it's a real thing." She said "does it have another name" and I said "it could be called a ball end." At that point she said she was "going to get the manager." Guy comes up with her and asks"what did you say to her." I told him "I was looking for heim joints." He turned to her and said "that's a real thing and we don't carry them." I left shaking my head. I can't make this up, the company name is Johnson Hardware.
Thanks guys and thanks for stealing the thread haha. Much better than some smartass comments you get on here sometimes. I needed that laugh I just wish I knew what she thought you meant by Heim Joint.
The female threaded bung is welded in to the unthreaded tube and should always have every thread in use. Naturally, due to leverage, the shorter the joint to the bung the stronger, but as long as the threads on the male have full length contact with the female threads you should be OK, but since I'm not an engineer and don't play one on TV.......
If you have full length thread contact on the male joint, there is no adjustment possible to shorten the linkage. And where does the lock nut go? Thread engagement should be at LEAST one diameters worth, up to 1 1/2. There is little strength to be gained as long as stresses are linear. IMO.
If you have a Heim on the other end as a adjustment point, I'd split the difference and and have an equal amount of threads showing at each end. Ultimately though you need to get a longer swaged tube or move the mounting points closer together. Many of the race car shops ( Tim McAmis, Haas Race Cars) can supply the tubes and you can have the ends welded into place. Bottom line is that you need more thread engagement in the tube especially in a suspension application no matter which way the movement will occur.
From my experience working with road racing teams, 1.5 times the diameter of the rod end was a minimum.
Thanks guys. I appreciate the input. So yeah I did quite a bit of research last night on heim joints and thread engagement. I think the standard starting point is at least the diameter length thread engagement of the bolt going into the rod. After my recent scary event in my '57 pickup where my throttle stuck wide open I am going over all of my vehicles and double checking connectors and bolts just to try and save myself some issues in the future. I figured checking all of these heim joints that were used in the build were a good place to start. I'm learning to not give people the benefit of a doubt.
Is there any particular reason that the jam nut is up against the heim body rather than against the end of the link? Roo
I don't think it's supposed to be that way. In my opinion, everything in the picture in the original post looks WRONG. If that heim joint is anything like the ones I have used, it must have all of 2 or 3 threads engaged.
The threads on a heim are not intended to fasten 2 objects together, like a nut and bolt do. The threads are an extension of the structural member they are threaded into and the thread reveal is minimum. I use 3 threads as a rule. If you need more than 3 threads for adjustment then you need to replace the structural member the heim is screwed into.
Yep, this is standard thread engagement minimum in structural engr, should apply to auto applications as well. Take a look at a late model vehicle where bolt / nut engagement is optimized, the bolt will extend out of the nut approx 1/2 or a full diameter, the automakers wouldn't add the extra length and money if they didn't have to. An 1/8 inch length on a couple million bolts is big money.
I'm guessing from the photo that the tube is too short if the adjustment is correct. There's no indication of how much thread is in the tube, but based on other heims it appears not much. I'll also just assume the jamb nut is up just for photos.
Heim joints don't last long on street cars. They are replaced regularly on race cars. It is better to have some kind of rubberized or insulated joint. Unless the rod end is just for support of a member.
On mil-spec applications, minimum thread engagement is 1.5 x the diameter, so almost everyone here is right.
My whole Jeep suspension front and back is Heim jointed and it has taken lots of abuse for almost 100,000 miles. I just had it up on my lift and greased it the other day and everything is just as tight as the day it was installed.
LOL this country fella walks into the feed store and asks for a flat bastard, the lady gets in a huff and the fella who owns the feed store explains that it is a flat file. So the next guy that comes in says I needs me a file, the lady knowing that it is going to make her sound really smart say, "Do you want a flat bastard?" he says, " Nope better give me one of those round Muther F . . .rs." Sorry I just could resist. Depending on the application you want 1 to 1.5 times the diameter of the fastener in the hole, in this case the diameter of the fastener would be the threaded end of the rod end. I have engaged in conversation with men who believed that the jam nut was part of the distance into the hole, I don't believe that but I do believe that once the diameter is enough and most of those guys that believe that 1.5 times the diameter are using the jam nut as part of the equation. So in answer to your question 1 time the diameter is enough, I personally like about half the length but 1 time the diameter should get you where you need to be.
Lady walks into the same "Johnson Hardware" to buy a hinge. While she's checking out, the guy behind the counter says, "Do you want a screw for that hinge?" The lady says, "No, but..." I'm sure you all know the rest.
The photo on the post is for reference. I had backed out the threads and loosened the nut to see how much actual thread material was inside the bung. The question was answered by the first replies. 1 1/2 times the width it is just to be safe. Thanks
Since this is still going,,,a story here,,,back in grade school days, '50's,.a best friend was a member of the Heim family, the founders grandson. We would visit the plant and 'borrow' a few rod ends to play with. Many years later, I still have some of them. A few years ago, I used a couple on a Moto Guzzi shift linkage.
Maybe it the Big Tool and Johnson Company. Big tool, big Johnson its about six of one or half a dozen of the other.
@Bigstar I have a 67 SS Nova that I put a late model Corvette IRS in ( both kinda OT for the Hamb). The car has been back halved and the half shafts are considerably shorter than original, so both the camber and toe adjuster rods needed to be custom made. I can't remember the guys name, but they made me some really neat swedged aluminum adjusters to the dimensions I needed, and quite reasonable in price too. In the case of a heavy truck like yours,I'd say the steel versions would be the better choice. I've seen application specific steel ones in the aftermarket(possibly Guldstrand). The one and one half rule of thread engagement is correct, as well as the point that @oj made about the number of threads showing for adjustments. When taking measurements for the camber adjusters, use an average dimension based on both up and down arcs from neutral. The toe adjusters should not need nearly as much adjustment as long as the wheels are straight at time of measurement.
Spherical Rod End is the correct term. The material the body and the bearing is made of is very important to the life of the rod end. JC
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