A Calibrated Pull Test Tool

[Floradawg]

Rick, I had learned in technical school that fine threads are stronger than coarse. I would assume (there I go again) that would be with everything else being equal.

[Frank S]

Rick you have to understand how AI functions. all AI is, is a glorified search engine. with information sources from every piece of accumulated data imaginable. It then compiles this information regardless if the data had been submitted by metallurgical engineers who have conducted testing, or from works of fiction. Also, we have to remember that AI is still in its infancy.
I often approach things in a different manner. A 1/4" grade 2 bolt according to several load charts has a theoretical breaking point of around 2000 lbf if the root diameter of the thread is reduced by half the load would be in theory 1/4 the original since there is 1 fourth the sectional area remaining which seems to be about what you came up with. Nut thicknesses for bolts run on average about 80% of the diameter of bolts respective to size and grade to yield the same holding strength as the bolts.
Bronze depending on the alloy can range from 25,000 PSi yield to 40,000 PSI yield So if a grade 2 bolt is 50,000 PSi (I personally believe they are lower than that) this would put the lower grade of bronze at half the strength. If the thread engagement is 1/4" the pull out should be around 800 lbs at a 2FOS
An online calculator somewhat bares out my line of thinking
https://a2zcalculators.com/science-a...oogle_vignette

But if memory serves from another of your threads you will not be relying on a single eye bolt

[rgsparber]

I agree with you about what information is used to train AI. It then calculates what word is most often used after the current word and uses it next. AI has zero comprehension. When it says things that aren’t true, we say it is hallucinating. I use AI in my technical writing. About 80% of the time it is great. The other 20% of the time it is laughable.

I do lift with two forged eyebolts. The smaller frames are around 200 to 250 pound so each eyebolt will see less than 125 pounds. The larger frame will be lightened by removing plaques so will be in the same weight range.

Rick

[Frank S]

If the frames have enough thickness/ width in the bolt areas to accommodate larger diameter threads but you still want or need to use the 1/4" eye bolts you could go another route. If you still have some concerns and it is not feasible to have more thread engagement. systems like Helicoil or nutserts greatly increase the pullout strength in a mirid of materials. Often times doubling tripling or even quadrupling the pullout strength depending on the type of inserts. IKEA would have gone out of business with its cabinetry lines without these being used in their MDF and particle board products. Automotive manufactures could not build their plastic cars without them. Almost every industry incorporates them somewhere, especially where the removal and reinstall of fasteners are required for teardowns and inspections involving Aluminum or composite components are used.

[rgsparber]

If the frames have enough thickness/ width in the bolt areas to accommodate larger diameter threads but you still want or need to use the 1/4" eye bolts you could go another route. If you still have some concerns and it is not feasible to have more thread engagement. systems like Helicoil or nutserts greatly increase the pullout strength in a mirid of materials. Often times doubling tripling or even quadrupling the pullout strength depending on the type of inserts. IKEA would have gone out of business with its cabinetry lines without these being used in their MDF and particle board products. Automotive manufactures could not build their plastic cars without them. Almost every industry incorporates them somewhere, especially where the removal and reinstall of fasteners are required for teardowns and inspections involving Aluminum or composite components are used.

Frank,

Thanks for the alternate solutions. I’ll look into them as I like to have backup plans.

Rick