FYI: General Torque Specs Per Bolt Size

[Jason in DLH]

I thought this might help someone out in the future if they can’t find torque specs for a nut/bolt...

 

[Greg Kulbick]

Small bolt = one ugga dugga.
Big bolt = two ugga duggas.

 

[NOSOK]

Looks like those #s correspond to grade 5 on the lower end and grade 8 on the high side.

 

[Jason in DLH]

Looks like those #s correspond to grade 5 on the lower end and grade 8 on the high side.

That sounds right.

 

[exp500]

Jason- you are teachin them the wong way! FSM has a torque for nearly everything, and a better generic chart showing hardness marks too!

 

[wjburken]

I use this app a lot.
https://apps.apple.com/us/app/iengineer/id369825047

 

[Jason in DLH]

Jason- you are teachin them the wong way! FSM has a torque for nearly everything, and a better generic chart showing hardness marks too!

That just came out of my Haynes repair manual. I’ll have to edit my post.

 

[Jason in DLH]

I use this app a lot.
https://apps.apple.com/us/app/iengineer/id369825047

Took a quick look at that and downloaded it immediately! I think it’s great it has lubricated torque specs as I’m always wondering about this.

 

[wjburken]

Took a quick look at that and downloaded it immediately! I think it’s great it has lubricated torque specs as I’m always wondering about this.

Sounds good. If I remember correctly, I had to pay a couple bucks to get the metric stuff, but it was worth it for me as a quick reference when I was designing equipment.

 

[Jason in DLH]

Sounds good. If I remember correctly, I had to pay a couple bucks to get the metric stuff, but it was worth it for me as a quick reference when I was designing equipment.

Yup...you’re right. I’ll probably just pay the couple bucks as well.

 

[exp500]

For me it's a trust thing, along with common sense/experience. Was just working on a differential, and the pinion torque was listed in the factory manual at 390-425 ft/lbs. 25 mm shaft, fine thread 1.75, 8-9 threads total in nut about 5/16 inch,with nut using a pin type 4 slot socket same as a 4x4 old style hub nut. No way that shaft/nut could handle that, or the socket! Still havn't gotten an official reply back. I already know the answer. Piss poor design, no lock other than the flange on the nut to be staked after torque into a fine 26 spline. Guaranteed to come apart sooner or later. So they upped the torque. Should be a mandatory recall.I'll bet they sell alot of parts, two or three times. Pinion shaft is $1400. Also, since it is a pinion, what about the bearings preload? I think they just moved the decimal on the torque spec. Not enough threads on pinion to change to a better design.

But back to TRUST, some copy/paste GoogAppl app idiot like above manager thats trying to save his skin or an app designer that has people driving into lakes following his directions. Which do you trust? I'll stick to factory, they have warranty/recall. And guys like me bitchin.

 

[exp500]

Wade-Just noticed when I was..... Didn't your boss or organization or Licensing affiliate (SAE for instance) Provide the tables for you? Licensing is a *****, opens you up for many liabilities. Surprised your school didn't cover that in depth.

 

[wjburken]

For me it's a trust thing, along with common sense/experience. Was just working on a differential, and the pinion torque was listed in the factory manual at 390-425 ft/lbs. 25 mm shaft, fine thread 1.75, 8-9 threads total in nut about 5/16 inch,with nut using a pin type 4 slot socket same as a 4x4 old style hub nut. No way that shaft/nut could handle that, or the socket! Still havn't gotten an official reply back. I already know the answer. Piss poor design, no lock other than the flange on the nut to be staked after torque into a fine 26 spline. Guaranteed to come apart sooner or later. So they upped the torque. Should be a mandatory recall.I'll bet they sell alot of parts, two or three times. Pinion shaft is $1400. Also, since it is a pinion, what about the bearings preload? I think they just moved the decimal on the torque spec. Not enough threads on pinion to change to a better design.

But back to TRUST, some copy/paste GoogAppl app idiot like above manager thats trying to save his skin or an app designer that has people driving into lakes following his directions. Which do you trust? I'll stick to factory, they have warranty/recall. And guys like me bitchin.

I completely agree that you should follow factory torque specs.

I use the app as a good guideline for torques. Critical applications get a lot more attention from me when I'm designing equipment, but the app gives a good starting point.

 

[Jason in DLH]

Yeah...that previous little table in the original post seems way off now that I’m looking into it more.

Example: Upper Strut Bolts are 17mm and are specified at 37Ft-lbs. The table shows that it should be greater than 140 Ft-lbs. The Haynes manual does say to follow the torque specs in the beginning of each chapter closely, but I have no idea why there would be so much discrepancy for the aforementioned example.

Thankfully I’ve never used the little chart as I’ve had specific torque specs.

I think perhaps I’ll ask a moderator to delete this entire post so as to not confuse anyone. Anyone know how about to request this?