Deciphering bolt torque requirements

[S854]

Reading through the owners manual of my new tractor (Kioti CK2610 HST, if it matters) I came across a couple of "torque tightening charts", one for metric, the other for ISO...the charts list "bolt sizes" and "grades"-- along with the minimum and maximum torque for each...

Other than the required torque on the wheel lugs, there is no other torque specs in the manual... I looked online for a service or repair manual and came up short...

I went to a website (BOLTDEPOT.COM) and came across a subheading--"BOLT HEAD/WRENCH SIZE"--which lists, for example, a "10mm bolt" which requires a "14mm" wrench... I could then assume the 14mm bolt head on my tractor would correlate to an M10 bolt... find the M10 torque specs in the manual and go from there... (I'm sure the whole process would take much less time to actually perform and it would take to read and understand my methodology...)

This seems like a rather convoluted method of coming up with the correct torque wrench settings for the various fasteners I'm checking, but if it works... what the heck, eh?

I'm thinking I'll double-check the fasteners before going full in... I.e. back out one of the bolts and measure the shank diameter, then compare this with the bolt head/shank size listed on the "BOLT HEAD/WRENCH SIZE" chart... (reading the bolt grade on the bolt head is a no-brainer)...

Does this method make sense?

 

[WranglerX]

Any quality bolt will have "type" stamped/embosses on bolt head... Wrench size doesn't determine what quality/torque requirements for bolts.....

THis has always been my go to documentation for reference to bolting and other things around the property.......

Pocket Ref by Thomas J. Glover (2010, Trade Paperback) for sale online | eBay

Example of pages...

And you can use a METRIC or SAE wrench to check bolt diameter, for instance a 10mm open end wrench slipped onto shank of bolt "snugly" will indicate bolt is probably 10mm, if wrench will not go on, the bolt shank is bigger, if it fits on sloppy loose the bolt shank is smaller.... Wrench is sort of fixed width calipers....

 

[S854]

yes... the charts you have are similar to the ones I found..

I guess to make my question more simple...

How do I determine if I'm dealing with a 1/4" or 5/16" bolt (without pulling the bolt out)...?

I'm trying to simplify maintenance by just checking the bolts...

Is there a standard relationship between bolt size and bolt head size?

 

[JasperFrank]

Woud love to see some one on Youtube, buy and test a bunch of graded bolts and see if they match their ratings.

 

[WranglerX]

yes... the charts you have are similar to the ones I found..

I guess to make my question more simple...

How do I determine if I'm dealing with a 1/4" or 5/16" bolt (without pulling the bolt out)...?

I'm trying to simplify maintenance by just checking the bolts...

Is there a standard relationship between bolt size and bolt head size?

By using wrench size on bolythead you can "guess" you are spot on, but only real (accurate) way is to pull the bolt and measure... There are some engineered product the do no use "standard" bolt head sizes to match bolt shank....

 

[WranglerX]

Woud love to see some one on Youtube, buy and test a bunch of graded bolts and see if they match their ratings.

Go to youtube and enter "Bolt Shear Test" in search box....

 

[S854]

I guess I could do a one-and-done bolt size measurement for the important fasteners (FEL mounts, ROPS etc.) and make notes regarding torque specs for each location… “two finger tight” would work for things like steps, fenders and such…

 

[rScotty]

Reading through the owners manual of my new tractor (Kioti CK2610 HST, if it matters) I came across a couple of "torque tightening charts", one for metric, the other for ISO...the charts list "bolt sizes" and "grades"-- along with the minimum and maximum torque for each...

Other than the required torque on the wheel lugs, there is no other torque specs in the manual... I looked online for a service or repair manual and came up short...

I went to a website (BOLTDEPOT.COM) and came across a subheading--"BOLT HEAD/WRENCH SIZE"--which lists, for example, a "10mm bolt" which requires a "14mm" wrench... I could then assume the 14mm bolt head on my tractor would correlate to an M10 bolt... find the M10 torque specs in the manual and go from there... (I'm sure the whole process would take much less time to actually perform and it would take to read and understand my methodology...)

This seems like a rather convoluted method of coming up with the correct torque wrench settings for the various fasteners I'm checking, but if it works... what the heck, eh?

I'm thinking I'll double-check the fasteners before going full in... I.e. back out one of the bolts and measure the shank diameter, then compare this with the bolt head/shank size listed on the "BOLT HEAD/WRENCH SIZE" chart... (reading the bolt grade on the bolt head is a no-brainer)...

Does this method make sense?

Do you mean does your method make sense or does theirs?

Your method makes sense to me if you are asking if you are interpreting a bolt/head torque chart correctly. But do you really want to fly that close to the sun?

I can see that their simple bolt chart makes sense for a basic operator's manual, requires no extra input from engineering, and provides a clamping pressure that works most of the time as long as the bolts are always bolting the same materials together. So it's a plus from manufacturing viewpoint. And good enough for an your operator's manual - which is where you say it comes from. I'd bet their shop manual is more specific.

The purpose of a torque spec is a subject for endless debates. When should it spec for clamping pressure & when for maximum safe stress on the bolt?

It's never simple. If it's safe bolt stress choice , then the assemption is that bolting an aluminum head to a cast iron block with a head gasket sandwiched in there has the same clamping requirement as a wheel and axle. Pretty clearly that's not always true.

But before we second guess them, we ought to give Kioti the benefit of double checking....
Go to their SHOP MANUAL, look into the repair sections - and see if their description of procedures for cylinder head torque or varioius hydraulic pump bodys includes special bolt torques for those components. I'm betting that they so.

rScotty

 

[S854]

Reading through the owners manual of my new tractor (Kioti CK2610 HST, if it matters) I came across a couple of "torque tightening charts", one for metric, the other for ISO...the charts list "bolt sizes" and "grades"-- along with the minimum and maximum torque for each...

Other than the required torque on the wheel lugs, there is no other torque specs in the manual... I looked online for a service or repair manual and came up short...

I went to a website (BOLTDEPOT.COM) and came across a subheading--"BOLT HEAD/WRENCH SIZE"--which lists, for example, a "10mm bolt" which requires a "14mm" wrench... I could then assume the 14mm bolt head on my tractor would correlate to an M10 bolt... find the M10 torque specs in the manual and go from there... (I'm sure the whole process would take much less time to actually perform and it would take to read and understand my methodology...)

This seems like a rather convoluted method of coming up with the correct torque wrench settings for the various fasteners I'm checking, but if it works... what the heck, eh?

I'm thinking I'll double-check the fasteners before going full in... I.e. back out one of the bolts and measure the shank diameter, then compare this with the bolt head/shank size listed on the "BOLT HEAD/WRENCH SIZE" chart... (reading the bolt grade on the bolt head is a no-brainer)...

Does this method make sense?

Where does one access this "SHOP MANUAL"?

 

[rScotty]

S854 writes: "Where does one access this "SHOP MANUAL"?

JUST FOR CURIOSITY, TONIGHT I GOOGLED YOUR TRACTOR: "Kioti CK2610 HST" & "WORKSHOP MANUAL". THERE ARE DOZENS FOR SALE - BOTH IN PRINT AND PFD. INCLUDING USED ONES ON EBAY. SO IF YOU REALLY ARE CURIOUS ABOUT HOW KIOTI HANDLES TORQUE SPECS ITS EASY TO FIND OUT.

Right. My apologies. I forgot that there isn't any way to know about those manuals if you haven't encountered them. But it's normal for every manufacturer and each model of tractor to have three manuals availiable: The Owners, Parts, and the Workshop or "Shop" manual. The Owner's manual is the only one you get with the tractor. The other two go into much greater depth and you have to order either one - best to get both - from the dealer just like you would any parts.

Sometimes they are available digital format, but more traditionally in print version - often in a ring binder.

Both the Parts and Shop manuals can run to several hundred pages and the text has chapters which discuss systems, changes, tests, repair procedures, and how the various systems operate together. The best of them have multi-color foldouts & drawings of how systems work.
That's where you can study what the pedal actually does to the HST to make it go, or how they expect the emissions system to work and what to look for when it doesn't.

Typical prices for Parts or Shop manuals are about $100 apiece in print or bound copies. Maybe less for digital. Eventually older digital ones make it to the internet and you can find them for free - but the printed ones sure are handy. People collect them. Lots for sale on ebay.

Messicks - a large dealer - sells manuals online for the tractors they sell... or used to sell.
rScotty