Click torqueing or degree?

I believe there are different torque specs for plated vs non-plated fastners as well.

I like the old beam type torque wrench with smaller values .

http://www.sears.com/craftsman-3-8-...MIyf3p_Nyf2wIVirxkCh06YA3MEAAYASAAEgLW0vD_BwE

On heavy torque pounds I go by what it took to break it loose . Pull the same hard when going back together .

While not mechanical as such, an electrical fire I was called out to rebuild, came to a lawsuit. I was subpoenaed as an "expert witness." (what a laugh.) One of the questions that came up, outside of my "expertise," was the torque of the switchgear. It came down to the fact that more than likely everything had been over torqued. Over torquing as other have pointed out stretches the bolts, when the copper bus gets a heavy electrical load on it, it expands as do all metals. (I think.) Anyway , over torquing the bolts allowed everything to stretch, then come loose and then over heat because of resistance due to poor connection. End result, a 3.5 million dollar fire that the original electrical contractor was on the hook for. My part was quite infinitesimal, but sitting there was very educational. 40 years ago, proper torque was "as tight as you could get 'er plus an additional nudge." With the new CAD equipment, everything is right on the nubbins with very little "over build." Torque now is so much more important because of cheaper manufacturing in buildings and associated equipment.

Alll low, medium, & high voltage connections will loosen over time due to the fact the electrical supply is AC rather than the actual load in amps on the switchgear. Part of the PM system on HV switchgear is to tighten all the hardware at least twice a year. My #2 & #3 sons both work in the electrical supply industry.
The voltage applied will vary from zero to circuit voltage, back to zero, then to negative circuit voltage and back to zero 60 times a second. Pull any electrical connector apart that has been used on an AC supply and you'll find the hardware will tighten. Tighten it and look at it again in 12 months time and it will again be less than tight rather than plain "loose".

Nige said:

Alll low, medium, & high voltage connections will loosen over time due to the fact the electrical supply is AC rather than the actual load in amps on the switchgear. Part of the PM system on HV switchgear is to tighten all the hardware at least twice a year. My #2 & #3 sons both work in the electrical supply industry.
The voltage applied will vary from zero to circuit voltage, back to zero, then to negative circuit voltage and back to zero 60 times a second. Pull any electrical connector apart that has been used on an AC supply and you'll find the hardware will tighten. Tighten it and look at it again in 12 months time and it will again be less than tight rather than plain "loose".

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This might be the reason the power company was not happy when the saw that the contractor who did some work on my house a few years back used connectors with set screws in stead of crimp connector at the main power feed lines to the house.

According to #2 son who was here to visit a few minutes ago, the latest UK Electrical Regulations (Part P, 17th Edition) call for all connectors on domestic installations that use screwed hardware have to be checked and re-tightened every 2 years. Remember that's on 230V 50-cycle AC, not 110V.

All that is interesting. Is there any different torque recommendations for bolts with loctite applied?

I was taught as a aircraft mechanic that the dial was more accurate.

cdm123 said:

I was taught as a aircraft mechanic that the dial was more accurate.

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Dial not beam! They still do not do degrees.

Tenwheeler said:

All that is interesting. Is there any different torque recommendations for bolts with loctite applied?

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Not AFAIK. The idea was to stop fasteners coming loose through vibration. Applying Loctite to a bolt indicates that no other product (e.g. oil or anti-seize) would be used at the same time, therefore you stick with the specified torque for the bolt.

If Loctite was considered to be some form of lubricant then a case could be made for reducing the torque on a fastener if Loctite was used where the specified torque was on a dry bolt. I've hever heard of this though.

I threw all the clicker torque's away years ago, to me dial torque wrenches seem to be far more accurate and stay accurate better than any clicker torque wrench. I like the degree torques on bolts, never had an issue on any I've ever used degree torques on.

I've never had an issue with any of the types. In the past I had enough feel in my hands to know when a wrench was weak and needed attention. For the most part anymore I pull things snug and do my own turn on the not so critical stuff anyway.

Or enough feel & experience where ya pull according to the bolt size like on rods , main bearing caps & heads .

It don't work everywhere ..... Some applications will use a big bolt with low torque value .

The 6-71 on the Ford uses 7/16 inch bolts that get pulled down to 20 foot pounds .

Any other time we would yank a 7/16 bolt to 55 pounds .

The clicker torques won't click is the issue I've had with them, on certain airplane parts, which are aluminum to start with and small bolts, some are torqued to 15 ft/lbs and have to be precise, we've over torqued them and ruined and stripped threads out by over torquing by even a few pounds. I've also twisted off head bolts that were torqued to yield with clicker torques before due to the clicker not working and being precise enough. For years we used dial torques as a standard to set the clickers to before doing precise work, just to double check the clicker torques, finally we just threw away the clicker torques and use only the dial torques. On small parts and low torque values one person can use a dial torque, on larger bolts and higher torques it takes two people, one to do the pulling and a second to read the dial.

On the clicker torques, you can have them calibrated before you torque to yield head bolts and before your done with all the bolts on the same head, the clicker can be off by a wide margin and you end up over torquing or under torquing bolts.

If you can "feel" a certain torque, lucky for you, personally I can't tell if I'm torquing a bolt to 28 ft lbs or actually torquing it to 38 ft lbs, but in aluminum castings and special bolts, the 10 lbs extra can mean stripped out threads in a hole. When we're doing higher torques, say over 200 ft.lbs or even much higher still, and depending on how long the day has been, I might be off by a whole lot depending on where your standing, what your standing on and how many interruptions we've had on the same project from start to finish and how many of them we've done before. When we get into those 500 plus ft lbs torque, again depending on how many bolts need torquing in the same day, I'd rather have a dial torque to read, just to be sure.

The same goes for taking things apart, I have one son who's strong as an ox, so when he goes by "feel" and depending on if he used lock tight, anti seize, or oil on the bolts or nuts, can mean me being able to even get the stuff back apart at all, more than once I've had to load a machine up, drag it home, put it in the shop, to get near the shop air and a really big impact to get the fricken part off he's put on.

Don't even start on lug nuts on semi's and trucks, I can't begin to count the times I've had a flat and someone's used the impact to rattle those fricken things on to the point not even an inch impact can get them off with heat applied besides and you end up twisting off the bolts to get the rim off, and those times its usually on a weekend, your out of cell service and its either raining or snowing or dark, or all the above and your usually late to either get the wide load off the road or about as far from home as you can physically get. So around my place, if you rattle nuts on to the point the impact can't possible give it any more, instead of using a torque wrench to do the final torquing, your also the same person who's going to go get them back off again, no matter the time of day or day of the week, weeks, months or years later when the rims need to come back off. Also when it comes to rims and tires on trucks, if you "don't" use anti seize on things as you put it back together, your the one who's going to try to figure out how to get those dayton rims off the hub, and if you twist off the bolts, your also the one who's going to pull the drums and hubs off to replace those bolts as well, no matter what the book says to install them dry and without anti seize.

Randy88 said:

Also when it comes to rims and tires on trucks, if you "don't" use anti seize on things as you put it back together, your the one who's going to try to figure out how to get those dayton rims off the hub, and if you twist off the bolts, your also the one who's going to pull the drums and hubs off to replace those bolts as well, no matter what the book says to install them dry and without anti seize.

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I know everyone says install lug nuts on trucks dry, but in the quarry I always used the anti-seize on them. 98% of the ten-wheelers we had used the cast spoke Dayton type wheels and between the stone dust and the muddy roads from watering the roads down to control dust running the lug nuts dry would almost guarantee you would have major problems when it came time to remove one. I always used one of those clicker type torque wrenches, a good Snap-On one. Now it may not have seen the constant use of say a wrench in a big fleet so it seemed to work just fine. I made it a point to recheck the torques on lug nuts within a day or two of replacing a wheel and most of the time only one or two would turn any amount.

Before I was doing almost every tire change it was very common to have wheels slip and damage valve stems or other problems. Back then it was common for other people to just hammer the lug nuts on with a 3/4 inch impact and call that good enough. Most important thing I felt was to have all the components clean of mud and rust scale then I preferred to use a 1/2 inch impact to tighten up and spin the wheel to make sure it was running true and then go to the torque wrench. Another thing I did that may not be considered right by some was to use SAE flat washers under the nuts on all the wheel wedges and I replaced them with new if the old ones were worn or distorted.

Now one also has to understand that the trucks I was dealing with probably never saw 25 mph empty or loaded but were loaded to the max a loader operator could fit in the box and ran on rough and uneven roads all the time. If working on trucks running 80 mph on Interstate highways doing 150,000 miles or more a year that might call for a different plan of attack!

After awhile pullin wrenches a feller can look at the bolt size & application and know how hard to pull on it . It takes a little time .

Ya just know when it's tight ....

I have an apprentice and he is big and strong and it is hard to get this across that some small bolts just don't need to be that tight.

I think I need to start packing a torque wrench so he can learn the correct feel for the sizes of fasteners.

kshansen said:

I know everyone says install lug nuts on trucks dry, but in the quarry I always used the anti-seize on them. 98% of the ten-wheelers we had used the cast spoke Dayton type wheels and between the stone dust and the muddy roads from watering the roads down to control dust running the lug nuts dry would almost guarantee you would have major problems when it came time to remove one. I always used one of those clicker type torque wrenches, a good Snap-On one. Now it may not have seen the constant use of say a wrench in a big fleet so it seemed to work just fine. I made it a point to recheck the torques on lug nuts within a day or two of replacing a wheel and most of the time only one or two would turn any amount.

Before I was doing almost every tire change it was very common to have wheels slip and damage valve stems or other problems. Back then it was common for other people to just hammer the lug nuts on with a 3/4 inch impact and call that good enough. Most important thing I felt was to have all the components clean of mud and rust scale then I preferred to use a 1/2 inch impact to tighten up and spin the wheel to make sure it was running true and then go to the torque wrench. Another thing I did that may not be considered right by some was to use SAE flat washers under the nuts on all the wheel wedges and I replaced them with new if the old ones were worn or distorted.

Now one also has to understand that the trucks I was dealing with probably never saw 25 mph empty or loaded but were loaded to the max a loader operator could fit in the box and ran on rough and uneven roads all the time. If working on trucks running 80 mph on Interstate highways doing 150,000 miles or more a year that might call for a different plan of attack!

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Worked the same on the road equipment but never used flat washers. Problem came from going behind a moron with a big air gun, messing up studs, mixing up wedges, crushing spacers and such.

I like deg. specs; A paint marker and impact is so much easier on my back. I hate to admit it but the old school guys are right that if you know your tools you can get within 5% with feel.

In some applications, specifically JD 6068 head bolts, on the final torque turn you can feel the bolt give and it almost feels like a torsional spring. In attempt to convince my helper I could feel when the bolt reached it's correct yeild I had him mark the bolts with a paint pin and go ahead and place the pull handle on the bolt , each time I was with in 5% .