Bolt torque specification

I've noticed quite a few people inquiring about correct bolt torque for specific applications lately. Sometimes it's because they don't have and can't find the manual for that equipment, or one doesn't exist.
Here is a chart that applies to any bolt, regardless of brand or manufacturer. It may not be exactly the same as what Allis or Oliver would say, but it is correct. Most any bolt on a tractor or other piece of farm equipment is likely grade 8.

http://www.engineershandbook.com/Tables/torque.htm

My hope is that the mods will find an easy way to make this available to anyone surfing this website.

Just a comment: The bolt torques published in the handbooks are the torque values to make full use of the strength of the bolt. The handbook can not talk to specific applications. The torque value for a specific application can only be found in the equipment manufacturers manual. Yes, the handbook value is an excellent reference however, there may be applications where the manufacturer selected a certain bolt size/grade but does not intend for the full torque (handbook) value be used. An example would be for bearing assembles with a spacer between the bearings. Tightening the bolt to the handbook value could crush the spacer reducing end play/over loading the bearings.

Torque values are listed on the left hand column on this site already. Good enough for a guide if in doubt.

(quoted from post at 14:26:54 05/16/19) Torque values are listed on the left hand column on this site already. Good enough for a guide if in doubt.
<img src="https://www.yesterdaystractors.com/cvphotos/cvphoto23250.png">

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Thank you for that critique. When I read it, I had no idea what you were talking about since when I visit this site there is nothing that looks like a left hand column. When I switch from modern view to classic view there is a left hand column. Having two completely different looks for this website may be causing confusion for others besides me.

To add to the other posts. I would not agree that it is safe to assume or say most any bolt on a tractor or other farm equipment is grade 8. I know many are grade 5 and some are grade 2 on the things I work on. Heads normally have industry standard markings you need to look at to see the grade to determine the torque for it. Head, rod and other bolts for specific applications may not have markings hence the importance of the manufacturer's info. Then you get into the base material, which the common standard torque charts don't account for. They allow for engagement into a material equal to the bolt to an industry standard depth. Is it a grade 8 bolt with a grade 8 nut or is it a grade 8 bolt threaded into cast iron or steel, and the depth? Those factors make a difference. I have worked in situations where we had torques for the grade of bolt based on what it engaged with.

Beloit made paper machines and one thing they did was used oversized (i.e. used 1/2 would have been 3/8 plenty strong) bolts and hardware spec'd out as grade 2 hardware. I asked one of their erectors why they did that. He said the theory was people anywhere could get hardware store bolts (which are often grade 2) if missing they were some and be ok when torqued to grade 2 specs. If a higher grade was used the grade 2 torque still applied.

Now metric hardware (grades 4.6, 4.8, 8.8 or 9.8, 10.9, 12.9) is found on a lot of equipment. I see a lot of 8.8's used and they can fail if torqued as a grade 8.

Manufacturer's specs first, then a generic chart after checking the fastener grade is the way I would recommend. JMHO

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Here

(quoted from post at 11:07:43 05/16/19)

(quoted from post at 14:26:54 05/16/19) Torque values are listed on the left hand column on this site already. Good enough for a guide if in doubt.
<img src="https://www.yesterdaystractors.com/cvphotos/cvphoto23250.png">

Click to expand...

Thank you for that critique. When I read it, I had no idea what you were talking about since when I visit this site there is nothing that looks like a left hand column. When I switch from modern view to classic view there is a left hand column. [b:e45e2e1cb9] Having two completely different looks for this website may be causing confusion for others besides me.[/b:e45e2e1cb9]

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The bolded would qualify as a bona fide understatement.