Posted by Clint Dixon [172.69.58.14] on Wednesday, October 30, 2024 at 19:21:34 :
In Reply to: Forged U Bolts Torque? posted by Steve [162.158.10.210] on Monday, October 28, 2024 at 17:00:46 :
Lets consider facts and just the facts:
1) Some models of our Power-Wagons and military Dodges were fitted with forged U-bolts, mainly the earlier models of trucks.
2) Some models of our Power-Wagons were fitted with formed (shaped) U-bolts, mainly the later models of trucks.
3) Formed U-bolts can be formed either by cold bending or hot bending. Either may then be heat treated, quenched and tempered.
4) Forged U-bolts are created by forging - as the name implies. It is a very hot, exacting, and high pressure process.
5) Forging, cold forming, and hot forming all introduce their own unique internal stresses within the U-bolt material.
6) Both forged and formed U-bolts can be created from various grades, qualities, and carbon (and other) contents of materials.
7) U-bolt threads can either be cut or rolled into the material.
8) Most (but possibly not all) of the early forged Power-Wagon U-bolts were manufactured with rolled threads.
9) 1/2-20 male U-bolt threads (I chose this thread size chosen as an example for discussion) will accept only 1/2-20 female threaded nuts. This rule applies to other thread sizes also.
10) Any uniquely designed threads (diameter, pitch, shape, etc.) that fall outside of the standard inch, metric, British, ACME, etc. require nuts of a likewise unique design. Others will not properly fit these unique treads.
11) Most (but maybe not all) Power-Wagons models (both early and late) were fitted with U-bolts and mating nuts of standard inch thread measurements.
12) The majority of male thread stretch and deformation that occurs upon a bolt, due to the proper torque of a female nut upon those threads, happens just past the point on the threads that the nut travels to in order to achieve said torque.
13) A negligible amount of thread stretch and deformation occurs (on the threads of both the bolt and nut) within the threads of each that remain in contact once the two are torqued properly together.
14) Any bolt thread that is over-torqued to the point that the material (base material and/or thread material) becomes stretched and deformed to the point that it will not return to its natural state (shape, length, condition, etc.) once the torque is released can be considered over-stressed, damaged, and weakened from the stretching and deformation.
15) The U-bolts fitted on our trucks were engineered for specific conditions, loads, and purposes.
16) Most (but possibly not all) of the U-bolts fitted on our trucks were produced from steel sourced here in the U.S.
17) Modern U-bolt sources are in the business to sell new U-bolts, not to have their potential customer base reinstall their previously used U-bolts.
I have absolutely no idea on how many times the U-bolts on my Power-Wagons my have been removed and reused again during assembly at the factory, during repairs at the dealership, during modifications at driveline shops, or by previous owners over the past 70 odd years.
I do know that I have personally stood right next to an operator and a hydraulically operated die at a nationwide driveline facility, that mainly caters to over-the-road freight hauling companies and truck manufactures, while said operator cold bent custom U-bolts for me. The high grades of steel material that I am accustomed to being used (and specified by our customers) to manufacture parts for Deere, CAT, Komatsu, Case, etc. in the machine shop where I work would have either snapped in two, or have become significantly compromised, if they had been cold bent to that degree.
I have more trust in the original parts found on my Power-Wagon than those that are modern reproductions, or those that may have been replacements sometime later in the truck's life.
My test for the condition of forged U-bolts (that appear to be original to the Power-Wagon) is visual first and foremost as I am the inspector where I work. I then select a proper deep nut commonly used on U-bolts and spin it completely down the entire length of the threaded legs of the U-bolt. This tells me the conditions of the threads and whether there is any stretch or deformation.
One can take it a step further and have U-bolts inspected by a metallurgical service such as those who check engine blocks for cracks.
Junior
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