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School me on picking size and material for links

Weasel said:
You could run a solid steel link and claim the same thing, Why not do that? It would be way stronger then any of that. Who is breaking 2" HT link, let alone 1.5" links? Have seen some fail due to bad HT or poorly welded inserts.

Actually I'd bet that a set of 2 HT links would be stronger then the above setup.
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You can bet all you want. Why don't you do some math and get back to me :laughing:
 
Lil'John said:
In that spreadsheet, what is the target cell I should be watching?
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Look at the "FS" cells which are your factor of safety to different failure modes (based on the vehicle information you listed and the acceleration loads you specify). As factor of safety less than 1 means it will fail with the calculated inputs. Assuming you are using fairly accurate inputs, I would shoot for a factor of safety around 2 (higher if you are less certain in the accuracy of your inputs) to account for shock loading and more complicated load cases than the calculator is predicting. The bending calculation is probably the most pertinent for crawlers.
 
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Weasel said:
Have seen some fail due to bad HT or poorly welded inserts.
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you answered why in your own post :homer: :flipoff2:

and some of us like doing everything ourselves not sending it off to some company in hopes they get the HT right

pretty sure this thread is about a trail rig and the OP included the comment "im not worried about weight" :homer: not a race car with high end parts and major concerns of weight savings
 
'84 Bronco II said:
You can bet all you want. Why don't you do some math and get back to me :laughing:
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I know you were talking to Weasel, but I got curious and used the calculator function described above.

48" long links

2.5x0.250 DOM shows PBending at 3,774 lb
2" OD 7075-t6 AL shows PBending at 4,791 lb
2x0.250 4340HT shows PBending at 7,159 lb

I'm assuming I'll add both the 2 results for DOM and AL slug in order to have an idea of the total. I know it has to be more than that since laminating material is stronger (correct me if I'm wrong) but at the end of the day "my" solution is stronger than 2.0x0.250 4130HT links.

I tried 2.5x0.250 4130HT and the result jumps up to 12,075 lb, making it a clear winner here.

Total weight of the AL slug is 15.6lbs which is about a total extra 62lbs on the rig. Far from being negligible.

I knew all this and am already convinced by HT chromoly, but , for the practical reasons described earlier, I stuck with slugged DOM and am happy with my choice.
 
Bebop said:
I know you were talking to Weasel, but I got curious and used the calculator function described above.

48" long links

2.5x0.250 DOM shows PBending at 3,774 lb
2" OD 7075-t6 AL shows PBending at 4,791 lb
2x0.250 4340HT shows PBending at 7,159 lb

I'm assuming I'll add both the 2 results for DOM and AL slug in order to have an idea of the total. I know it has to be more than that since laminating material is stronger (correct me if I'm wrong) but at the end of the day "my" solution is stronger than 2.0x0.250 4130HT links.

I tried 2.5x0.250 4130HT and the result jumps up to 12,075 lb, making it a clear winner here.

Total weight of the AL slug is 15.6lbs which is about a total extra 62lbs on the rig. Far from being negligible.

I knew all this and am already convinced by HT chromoly, but , for the practical reasons described earlier, I stuck with slugged DOM and am happy with my choice.
Click to expand...

Thanks for posting the numbers, I was too lazy to do it myself. Simply adding the bending strength of the aluminum and the steel is probably close enough for this discussion, but the differences in elastic modulus and yield strength will impact the combined bending strength.

The other things worth pointing out are that the calculator is using a fairly extreme temper for 4130, so the calculated strength could vary significantly from what people are actually running, and the calculator doesn't account for dent strength which is important, but hard to easily characterize. You could calculate bending strength of a sheet of material at the wall thickness to get an idea of how a strong material with a thinner wall will compare to a weaker material with a thicker wall in that respect. With the calculations the calculator is performing, you could come to the conclusion that really large O.D. links with a thin wall are superior, when in reality they would buckle the as soon as they get a dent in a crawler application.
 
Bebop said:
My shocks and sway bar are mounted on the links, so I'd like to set up the mounts myself. Prior to HT.

I can TIG weld and wouldn't have any issues fabricating my own. Nor I'm arguing about the strength benefits of HT links.

My only problems are mentioned above and you're no help.
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Yeah so trailing arm, that's is a bit harder. I guess I missed that part of your post.

'84 Bronco II said:
You can bet all you want. Why don't you do some math and get back to me :laughing:
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meh why and I'm mathed out. I don't know how you would do laminate materials, adding them up isn't right I know that.

HT43xx should be in the 180-220K range. 110k seems pretty low.

rockyota83 said:
you answered why in your own post :homer: :flipoff2:

and some of us like doing everything ourselves not sending it off to some company in hopes they get the HT right

pretty sure this thread is about a trail rig and the OP included the comment "im not worried about weight" :homer: not a race car with high end parts and major concerns of weight savings
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Oh really so you make your own diffs and transmissions and transfer case. :homer::flipoff2::flipoff2:

The cheapest prob would be what someone else posted of sticking round tube in squared tube.

Another option I've seen done is to weld angle iron down the tube length to stiffen the impact edge. Also to repair bent stuff but it worked well enough.

WOD has really good prices on 2.25 or 2.5 AL solid. It slides well enough on rocks.
 
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Weasel said:
Another option I've seen done is to weld angle iron down the tube length to stiffen the impact edge. Also to repair bent stuff but it worked well enough.
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thats something i would do, ive done it to a tie rod
 
been doing links and steering bars from old 51mm and 45mm top hammer drill rods. heat treated, but still machinable and can tap threads

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Bebop said:
I know you were talking to Weasel, but I got curious and used the calculator function described above.

48" long links

2.5x0.250 DOM shows PBending at 3,774 lb
2" OD 7075-t6 AL shows PBending at 4,791 lb
2x0.250 4340HT shows PBending at 7,159 lb

I'm assuming I'll add both the 2 results for DOM and AL slug in order to have an idea of the total. I know it has to be more than that since laminating material is stronger (correct me if I'm wrong) but at the end of the day "my" solution is stronger than 2.0x0.250 4130HT links.

I tried 2.5x0.250 4130HT and the result jumps up to 12,075 lb, making it a clear winner here.

Total weight of the AL slug is 15.6lbs which is about a total extra 62lbs on the rig. Far from being negligible.

I knew all this and am already convinced by HT chromoly, but , for the practical reasons described earlier, I stuck with slugged DOM and am happy with my choice.
Click to expand...



So could you do a comparison for 2x2x.250 sq and 1.5" x.120DOM say 40" long? Compared to 2.5" 7075
 
You could :)

But remember that sq tubing has a different moment of inertia depending if you're working it on the flats or on the edges.
 
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I assume when making the 4130HT links, you weld on the tube adapters.....then send it out for the HT? I assume again that you really need to make sure the tube adapters are also made from 4130? What filler rod? ER80s-D2?

Can heat treated 4130 be welded?
 
gt1guy said:
I assume when making the 4130HT links, you weld on the tube adapters.....then send it out for the HT? I assume again that you really need to make sure the tube adapters are also made from 4130? What filler rod? ER80s-D2?

Can heat treated 4130 be welded?
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Yes. So like Bentfab welds the inserts himself and does the whole process. He said it's one less variable for him if he does the inserts himself. If your going to HT you would use 4130 filler and inserts, other wise they will be weaker then the rest of the link. I highly recommend him, I have a set of 1.5" for upper on a race ZJ I'm working on and he answered all my question, even the dumb ones. He does run batches so there is some time involved.

It can be welded but you will loose some strength where you heat it back up. I don't know the exact effects, Spidertrax used to sell HT housing's and didn't seem to have a issue with people welding links on the afterwards. That might have changed but at the time it didn't seem like it changed the overall strength that much. Depends what your welding to it and how big of any area, like a truss would have a larger effect then a link bracket or a gusset. But with a HT housing you shouldn't need a truss either. If welding on a HT whatever I'd use ER70 or 80 and preheat it a bit. Paul or the guys at Spidertrax probably have a process they would recommend.
 
Weasel said:
Yes. So like Bentfab welds the inserts himself and does the whole process. He said it's one less variable for him if he does the inserts himself. If your going to HT you would use 4130 filler and inserts, other wise they will be weaker then the rest of the link. I highly recommend him, I have a set of 1.5" for upper on a race ZJ I'm working on and he answered all my question, even the dumb ones. He does run batches so there is some time involved.

It can be welded but you will loose some strength where you heat it back up. I don't know the exact effects, Spidertrax used to sell HT housing's and didn't seem to have a issue with people welding links on the afterwards. That might have changed but at the time it didn't seem like it changed the overall strength that much. Depends what your welding to it and how big of any area, like a truss would have a larger effect then a link bracket or a gusset. But with a HT housing you shouldn't need a truss either. If welding on a HT whatever I'd use ER70 or 80 and preheat it a bit. Paul or the guys at Spidertrax probably have a process they would recommend.
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Metal Treating & Research out of Denver are the guys that did the housings for Spidertrax. Usually heat treating was done after ALL of the welding was complete.
 
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Aisin said:
Metal Treating & Research out of Denver are the guys that did the housings for Spidertrax. Usually heat treating was done after ALL of the welding was complete.
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When they sold a bare HT housing some welding is going to have to be done at some point. RockBug was the only one I think that was completed then HT?

Stephen Wilson said:
When welding the HT will be lost in the HAZ. I'm Google could find the actual temp. threshold that determines how far into the HAZ. the effect extends.
edit, apparantly down to about 1050 degrees. The visible HAZ shows where the metal reached at least 460 degrees.
http://www.netwelding.com/heat_trea...uraging welding,strength and may contain some
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:beer:
 
Stephen Wilson said:
When welding the HT will be lost in the HAZ. I'm Google could find the actual temp. threshold that determines how far into the HAZ. the effect extends.
edit, apparantly down to about 1050 degrees. The visible HAZ shows where the metal reached at least 460 degrees.
http://www.netwelding.com/heat_trea...uraging welding,strength and may contain some
Click to expand...

Very informative page.

Unless I'm reading it wrong, it seems if you were to weld a heat treated tube to a untreated tube adapter, the tube side of the HAZ at it's weakest point would still be at least as "strong" as the untreated tube adapter.

If that's the case, you could use thinner walled 4130HT tube to build links slugged with aluminum. Kind of a best of both worlds.
 
Yeah, it doesn't seem like tube adapters would be an issue. but more extensive welding of tabs or gussets in the tube run would be an issue. It all depends on how large the HAZ area is vs. any strength added by the tab/gusset.
 
Thanks to you guys and this thread, I just ordered a set of 4130 HT upper and lower links from Paul at Bent Fab in AZ. Great guy to work with and really knows his shit.

My lowers are 50.5" in front and 40.125" for the rear, figuring the rig will be 6k when it's finished. That's a good recipe for bent links. So we settled on 2.5"x .500" 4130 HT, which should give me a FS of 3 with the whole weight on a single link. Sure they'll be heavy, but at least it's down low. Uppers are going to be 1.75"x.120" 4130 HT.
 
gt1guy said:
Thanks to you guys and this thread, I just ordered a set of 4130 HT upper and lower links from Paul at Bent Fab in AZ. Great guy to work with and really knows his shit.

My lowers are 50.5" in front and 40.125" for the rear, figuring the rig will be 6k when it's finished. That's a good recipe for bent links. So we settled on 2.5"x .500" 4130 HT, which should give me a FS of 3 with the whole weight on a single link. Sure they'll be heavy, but at least it's down low. Uppers are going to be 1.75"x.120" 4130 HT.
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Lol, ridiculously overkill. 2"x1/4" 4130HT probably would have been OK. 2.5" x 1/4" 4130HT definitely would have been OK....
 
A6FA39D3-DFBE-45A4-B954-03927DB9A6D8.jpeg


Bumping this…I don’t have overly long links. 38in eye to eye. Tube itself including insert is about 32in. 2in .25wall. Completely fucked.

I don’t trust aluminum, I am thinking I’ll try 2in .25wall chromoly from bent fab
 
06h3 said:
A6FA39D3-DFBE-45A4-B954-03927DB9A6D8.jpeg


Bumping this…I don’t have overly long links. 38in eye to eye. Tube itself including insert is about 32in. 2in .25wall. Completely fucked.

I don’t trust aluminum, I am thinking I’ll try 2in .25wall chromoly from bent fab
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my passenger side is just like that also. same size tube and length also. i may try a solid insert of AL.. who knows
 
While heavy and expensive, 2 inch dia 1/2 wall ht4130 lowers will last the life of any average weight buggy/vehicle. 2.5 even more so. I slammed and drug mine for 7 years straight, the rash on them would not cut you if you ran your hand over it. Fn heavy though.
 
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