What Grade bolt is this?

[Sawyer Rob]

Using "anti seize" will cut down on corrosion between the two metals...

SR

 

[SPYDERLK]

I have had to replace the shear bolt on my brush hog, I always use the cheap bolt to protect my gearbox.

My concern would be the bolt failing while in the process of setting my trap and have something go flying causing damage or injury to anyone that happens to be around it.

In the case of the school bus bolts, I would think that they would have sheared off at a lower impact.

Too much smear on Gr2 for shear use.

I applaud your thinking on Gr5 vs 8 tufness:
Fasteners: Making the Grade - A Technical Discussion - RockCrawler 4x4 and Offroad MagazineRockCrawler 4×4 and Offroad Magazine

 

[brokenknee]

Too much smear on Gr2 for shear use.

I applaud your thinking on Gr5 vs 8 tufness:
Fasteners: Making the Grade - A Technical Discussion - RockCrawler 4x4 and Offroad MagazineRockCrawler 4×4 and Offroad Magazine

Thanks, that was a good read.

 

[DFB]

That odd marking you see on the head is the manufacturer mark

If your curious who produced it you may be able to match it at the Federal registry list of active insignia

National trademark registry

 

[SPYDERLK]

Here is a list of bolt grade markings and their strengths.

This list has a more specific list of strengths for different size bolts.

Bolts with non-typical markings may not be made to any specific code. Check the one you have with a magnet to see if it's an off brand stainless.

You should not automatically increase bolt strength grades. Certain applications require certain properties. A grade 2 bolt will have greater stretch before failing than a grade 5 and provide a cushion of sorts when forces exceed it's strength. I can give an example of this. Back in the 90s some school buses had the seats attached with grade 8 bolts. Studys found that during a crash these bolts would fail suddenly and cause greater injury. A recall was issued to replace all the seat bolts with grade 5. The grade 5 bolts while not having the same tensile strength would stretch and create some cushion when they failed.

Some PTO driven implements that use a shear bolt will require a grade 2 bolt to protect the gear boxes. People often replace those with grade 5 or 8 bolts to reduce the frequency of failure but they do so at the risk of damaging the gear box or PTO components.

I have had to replace the shear bolt on my brush hog, I always use the cheap bolt to protect my gearbox.

My concern would be the bolt failing while in the process of setting my trap and have something go flying causing damage or injury to anyone that happens to be around it.

In the case of the school bus bolts, I would think that they would have sheared off at a lower impact.

Too much smear on Gr2 for shear use.

I applaud your thinking on Gr5 vs 8 tufness:
Fasteners: Making the Grade - A Technical Discussion - RockCrawler 4x4 and Offroad MagazineRockCrawler 4ï¾—4 and Offroad Magazine

Thanks, that was a good read.

:thumbsup: ... The question remaining for the bus seat issue is the comparative Energy [FxD] in shear of Gr5 vs 8. There is no doubt that the 8 requires more force ... but is it for <, =, or > distance. I guess I could make a rigid setup to test empirically with my post pounder, but that would take a lot of time to find and deal with suitable fixture materials that would not immediately be damaged and inaccurate for comparison. Ill try to get an answer from a Finite Element Analysis guy I know.

Regardless, in the bus, give in the structure around the seat bolts will absorb/dissipate more energy with use of a stronger bolt, and cause a factor in favor of the stronger bolt. It could be an overriding factor.

 

[PSEbowhunter]

Thank you, I was reading a review on another trap-setter and the person doing the review stated that his bolt broke when trying to set his 330. I was just wondering if I should replace it with a grade 5 stainless. The reason I would go stainless as this is an aluminum setter. It does have sheet metal over the pivot point, I think for added strength. I am also considering pulling those off and placing some rubber pond liner I have on hand between the two.

The reason for this is because I am concerned about electrolysis of the metals.

The largest trap I have is a 220, 330 is not allowed above water in MN from what I understand, and I have no intention on going out trapping beaver.

You won't break that bolt setting duke 220's. I set our bridger and belisle 220s by hand. The 330s get the setter though.

 

[brokenknee]

That odd marking you see on the head is the manufacturer mark

If your curious who produced it you may be able to match it at the Federal registry list of active insignia

National trademark registry

Thank you, the marking is what through me off.