Build Project: Midnight Panic

SLOWPOKE693 said:
I see it on equipment that weights hundreds of thousands of pounds every day that are worked harder and vibrate more than any race car, and its not a problem because the bolts are torqued properly. If you think equipment has bolts that are all the proper shoulder length for the span they go through you would be highly mistaken. They rely on torque to keep the parts from moving. Ive never had to retorque bolts on equipment....
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I don't think your getting my point. Also....
Ghetto Fab. said:
What is the downside to bolts that are properly shanked?
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The house bearing on the drills we sell dont move around when you change directions quickly. Its not because the bolts are properly shouldered, they are not, its because the mechanical friction created from the bolt torque doesn't let the bearing move back and forth. You would probably **** yourself if I told you all our hydraulic motors are held onto the reduction units with fully threaded short bolts with no shoulders....
 
SLOWPOKE693 said:
The house bearing on the drills we sell dont move around when you change directions quickly. Its not because the bolts are properly shouldered, they are not, its because the mechanical friction created from the bolt torque doesn't let the bearing move back and forth. You would probably **** yourself if I told you all our hydraulic motors are held onto the reduction units with fully threaded short bolts with no shoulders....
Click to expand...
So are you arguing that properly shanked bolts don't have to be torqued? I think the point your missing is that the bolts have to be properly torqued EITHER way. So you don't loose anything with a properly shanked bolt, other than some time, but you could gain a bit of a safety margin.
 
Ghetto Fab. said:
So are you arguing that properly shanked bolts don't have to be torqued?
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Who the **** said that???

Ghetto Fab. said:
I think the point your missing is that the bolts have to be properly torqued EITHER way. So you don't loose anything with a properly shanked bolt, other than some time, but you could gain a bit of a safety margin.
Click to expand...

Using higher grade bolts that can be torqued to a higher value, and therefore give more mechanical grip to the joint to keep from moving and needing the shoulder is a higher saftey factor in my opinion.
 
Full shank bolts have a higher spring rate than threaded ones. This makes a difference in how much something moves when you exceed it's limits. Overall bolt length plays into this too. I prefer proper shank length, plenty of bearing surface with a tight hole. It's just extra insurance because I haven't calculated the actual loads and am just guessing. Washers are another issue, hardened washers are a must at those torque levels. Need to spread that load out so your soft tabs don't squish.
 
clamping force or clamping load in the case of this chart is what he is referring to.

1754629733375.png
 
Gonna be blasphemy to suggest this but these type of questions are REALLY bad ass to pose to Ai...

We have a bolt/joint problem and I've been reverse engineering some of the manufacturer data/instructions to see what impacts their torque changes make.
You have to be really accurate with this information but the math will math and you can get a much better idea of your clamp loads on your DIY joints. Most importantly make sure you aren't exceeding the proof load of your fastener.
 
Grendel said:
So, the OP actually takes his monster truck out for the first event... and y'all are ****ting up his thread arguing about bolts? Where the hell is arse_sidewards the OG thread ****ter? :flipoff2:

How about a different thread?
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We like to keep the thread bumped :flipoff2:

As an example...
3/4-16 grade 9 bolt 5" long clamping his 4" assembly (guess)
The final clamp (preload) is the target we used: 48,671 lbf (≈ 216.5 kN).

for a 5" long 3/4"-16 grade 9 bolt clamping a joint that is 4" thick what is the correct pre torque and torque turn degrees using a .2 nut factor to get get 90% of the proof load

ChatGPT said:​


Thought for 52s
Nice — let’s do the math. I’ll show the assumptions, formulas, and the step-by-step numbers so you can verify or change any assumption (for example a different proof stress, different nut-factor, or a different pre-torque percentage).

Assumptions I used​

  • Bolt: 3/4"-16, SAE Grade 9.
    I used a proof stress = 145,000 psi (common value quoted for Grade 9 / high-strength alloy inch bolts). Halsey ManufacturingEngineering ToolBox
  • Desired preload: 90% of the proof load (you requested 90%).
  • Nut factor (K): 0.20 (you specified).
  • Grip (g) / loaded length: 4.00 in (you stated joint thickness = 4").
  • Elastic modulus (E) for steel: 30,000,000 psi.
  • Thread pitch: 1/16 in per turn (3/4"-16 → 16 TPI → pitch = 1/16 in).
  • Pre-torque (snug) chosen: 10% of final torque (common practical choice — if you want a different % say 20% I can recalc).
  • Torque–tension relation used: T=K⋅D⋅FT = K \cdot D \cdot FT=K⋅D⋅F (standard approximation). Repair Engineering
If you want different assumptions (e.g., proof stress from a different spec, or using a measured nut factor) tell me and I’ll re-run the numbers.

REDACTED for post length​

Calculations (results)​

  • Stress area AsA_sAs for 3/4-16 (using the formula above):
    As=0.37296 in2A_s = 0.37296\ \text{in}^2As=0.37296 in2.
  • Proof load (full proof): Fproof=(proof stress)⋅As=145,000 psi×0.37296=54,079 lbf.F_{proof} = (\text{proof stress})\cdot A_s = 145{,}000\ \text{psi}\times0.37296 = 54{,}079\ \text{lbf}.Fproof=(proof stress)⋅As=145,000 psi×0.37296=54,079 lbf.
  • Target preload (90% of proof):
    Ftarget=0.9×54,079=48,671 lbf\boxed{F_{target} = 0.9\times54{,}079 = 48{,}671\ \text{lbf}}Ftarget=0.9×54,079=48,671 lbf.
  • Final torque (to produce FtargetF_{target}Ftarget) using T=KDFT = KDFT=KDF with K=0.20K=0.20K=0.20, D=0.75D=0.75D=0.75 in:
    T=0.20×0.75×48,671=7,300.7 inch-lb=608.4 ft-lbT = 0.20\times0.75\times48{,}671 = 7{,}300.7\ \text{inch-lb} = 608.4\ \text{ft-lb}T=0.20×0.75×48,671=7,300.7 inch-lb=608.4 ft-lb.
    Tfinal≈608 ft\cdotplb (≈825 N\cdotpm)\boxed{T_{\text{final}} \approx 608\ \text{ft·lb} \ ( \approx 825\ \text{N·m} )}Tfinal≈608 ft\cdotplb (≈825 N\cdotpm). Repair Engineering
  • Pre-torque (10% of final torque) (chosen snug):
    Tpre≈61 ft\cdotplb (≈82 N\cdotpm)\boxed{T_{\text{pre}} \approx 61\ \text{ft·lb} \ ( \approx 82\ \text{N·m} )}Tpre≈61 ft\cdotplb (≈82 N\cdotpm).
    That pre-torque produces a preload of about 4,867 lbf4{,}867\ \text{lbf}4,867 lbf.
  • Degrees of turn after pre-torque to reach the target preload:
    Using bolt stiffness k=AsE/L=0.37296×30×106/4=2.797×106 lbf/ink = A_s E / L = 0.37296\times30\times10^6 / 4 = 2.797\times10^6\ \text{lbf/in}k=AsE/L=0.37296×30×106/4=2.797×106 lbf/in and pitch = 1/16 = 0.0625 in/rev, the additional rotation needed is about 90.2° (≈ quarter-turn).
    θ≈90∘\boxed{\theta \approx 90^\circ}θ≈90∘

Summary (short)​

  • Final torque to reach 90% proof: ≈ 608 ft·lb (≈ 825 N·m).
  • Suggested pre-torque (10% of final): ≈ 61 ft·lb (≈ 82 N·m).
  • Additional rotation after pre-torque: ≈ 90° (quarter turn).

REDACTED for post length​

If you want I can:
  • Recalculate with a different K (e.g., 0.14 for lightly oiled, or 0.12 for machine-finished), or
  • Use 20% pre-torque instead of 10%, or
  • Give turn-of-nut only procedure (no torque wrench) starting from snug, or
  • Show the full step-by-step spreadsheet of the calculations.
Which would you like me to do next?


You said:​

Yes recalculate with turn of nut only with 20% pre torque.

ChatGPT said:​


Thought for 13s
Nice — done. I used the same assumptions as before (3/4-16 Grade 9, proof stress = 145 ksi, stress area = 0.37296 in², nut factor K = 0.20, grip = 4.00 in, pitch = 1/16 in/rev). You asked for a turn-of-nut only procedure where the initial snug is a 20% pre-torque (i.e. pre-torque = 20% of the final torque), then finish by turning the nut the required degrees.

Results (rounded)​

  • Target preload (90% of proof): 48,671 lbf.
  • Final torque (theoretical, from T = K·D·F): ≈ 7,300.7 in·lb = 608.4 ft·lb = 825 N·m.
  • Pre-torque (20% of final): ≈ 1,460.1 in·lb = 121.7 ft·lb = 165 N·m.
    That pre-torque produces a preload of ≈ 9,734 lbf (≈ 20% of the target preload).
  • Additional preload required after pre-torque: ≈ 38,937 lbf.
  • Turn-of-nut required after pre-torque: ≈ 80.2° (≈ 0.2227 revolutions).

What to do, step-by-step​

  1. Apply the pre-torque: 121.7 ft·lb (165 N·m).
  2. From that condition, turn the nut 80° (i.e., just under a quarter turn) to reach the target preload (≈ 90% of proof).
  3. Optionally verify with a calibrated tension-indicating method if available.

REDACTED for post length​


You said:​

what is the final clamp load for that

ChatGPT said:​


Thought for 5s
The final clamp (preload) is the target we used: 48,671 lbf (≈ 216.5 kN).

That’s based on 90% of the Grade-9 proof load used in the earlier calc (proof load ≈ 54,079 lbf → 0.90× = 48,671 lbf).
Practical note: torque-to-tension scatter (lubrication, thread condition, nut factor uncertainty) can make the actual clamp load vary ±10–20% from this value. If you need a tighter tolerance, use a direct tension-control method (strain-gauged bolts, load-indicating washers, ultrasonic, or calibrated test data).
Click to expand...
 
SLOWPOKE693 said:
Using higher grade bolts that can be torqued to a higher value, and therefore give more mechanical grip to the joint to keep from moving and needing the shoulder is a higher saftey factor in my opinion.
Click to expand...
You can change it however you want, but the same idea still applies. Get the shoulder of the bolt all the way through the mount. I've never argued using smaller, lower grade, non-torqued fasteners. You can have it all, large, high grade, high torque fasteners, and still get the shoulder of the bolt through all the mounting tabs. My argument is why wouldn't you if you've done all the other work? Technically you don't even have to cut the excess thread off the bolts either, it just looks goofy if you don't.
 
gt1guy said:
Didn't he say this was more of a test before taking the time to drill out a bunch of holes to 1"?
Click to expand...

He said he would go bigger if the 3/4" bolts don't stay tight. He also never said he was going to cut down 1" bolts, just go bigger.

Guys that work on and around heavy equipment understand exactly where his thought process is coming from because we see it in use every day.
 
Man I’ve missed a great conversation over the last few days!
We’ve been so crazy busy since last Thursday I’ve barely been online at all,
I’m still crazy busy the rest of this days off but I did want to jump on here & post a few pics, while also pointing out I did have a mechanical issue, well, might be equally hydraulic related.
The first night freestyle I ended up breaking both ends off the hydraulic cylinders,
IMG_2957.jpeg


Initially I blamed the Chinese parts & welding, (I still do to a certain extent)
I spent the next morning welding those eyes back on the cylinder rods, then grinding the Weiss out on the barrel end & rewelding those just for good measure, that night the cylinders held up, but I could feel the rear steer had something going on that wasn’t quite right, borderline flopping from center uncontrollably, but it would always return. So I knew it wasn’t broke again,
We did get the next two shows done without damage or failure,
But after making the over night trek from Santa Rosa up to just north of Portland, I ended up braking the cylinders again, this time breaking the swivel eye right at my weld,
I’m starting to believe the solenoid valve for the rear steer just can’t stop the fluid once in motion, so the cylinders just hit the end of their travel & something has to give,
I have to figure out if the valve is damaged, not heavy duty enough, maybe I need more surface area at the cylinders for the valve to hold agains, or I may possibly have to add a flow control valve or two of some time to control the returning oil,
When I get the truck out of the trailer I’ll be digging into this issue first thing,

I’ve got several things I want to mess with, but rather than list them out here, I’ll just make good posts detailing what I’m doing, why I’m doing it,,,,while I’m getting it done,

For now I’ll just post a few pics & point out that I’m not disappointed in the truck at all for its first time out.
IMG_2972.jpeg

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IMG_2973.jpeg

IMG_2970.jpeg

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