An Alternate Way to Think About Tightening a Nut

[rgsparber]

Have you ever thought about what is going on inside a stud when you tighten the nut? I learned about a machine at the Palo Verde Nuclear Power Plant that turned my thinking upside down.

If you are interested, please see

http://rick.sparber.org/SPTX.pdf


Your comments are welcome. All of us are smarter than any one of us.


Thanks,

Rick

rgsparber.ya@gmail.com
Rick.Sparber.org
You Tube Channel: https://www.youtube.com/user/rgsparber1
KG7MQL

[Ralphxyz]

Thanks Rick, now that is a interesting idea. Not sure where but I am sure I will use it.

It is interesting to break free a nut.

I wonder if you had a frozen bolt say 3/4" if you drilled and taped the bolt for a 3/8" rod if you could tension the bolt and break it free with tension.

Thanks again.

Ralph

[Trojan Horse]

Thanks Rick, now that is a interesting idea. Not sure where but I am sure I will use it.

It is interesting to break free a nut.

I wonder if you had a frozen bolt say 3/4" if you drilled and taped the bolt for a 3/8" rod if you could tension the bolt and break it free with tension.

Thanks again.

Ralph

Hi Ralphxyz,
That is possible, depending of course upon the strength of your 3/8" rod and how tight the 3/4" bolt has been torqued. If the 3/4" bolt has been torqued way past the capabilities of the 3/8" rod, then you would never be able to stretch the 3/4" bolt enough to be able to loosen it. However, if the 3/4" bolt has been torqued within the capabilities of the 3/8" rod, then it should work.

Hi Rick, I have both seen and learned about fastener stretch many times over the years. I worked for over 26 years in a diesel/natural gas-fired power plant. While we never had to contend with something like the pressure vessel described in your article, we did have to work with many large fasteners from 3 1/4" stud nuts and down. We used nut runners and torque multipliers to speed up working with the large fasteners. One of our torque multipliers was capable of over 3000 ft lbs of torque using just the input from a 3/8" drive ratchet or breaker bar and a 2" diameter "reactor" bar. The reactor bar was used to prevent the torque multiplier from spinning and was usually braced against the nearest, strongest support we had in the immediate area. Example: When torquing down the 3 1/4" engine base stud nuts, we braced the reactor bar against the engine block.
Thanks for the article, it was interesting.

[o1reb]

very common method for marine diesel engines

[jmparker98223]

Have you ever thought about what is going on inside a stud when you tighten the nut? I learned about a machine at the Palo Verde Nuclear Power Plant that turned my thinking upside down.

If you are interested, please see

http://rick.sparber.org/SPTX.pdf


Your comments are welcome. All of us are smarter than any one of us.


Thanks,

Rick

rgsparber.ya@gmail.com
Rick.Sparber.org
You Tube Channel: https://www.youtube.com/user/rgsparber1
KG7MQL

Seagoing ship propellers are held on by hollow bolts that are stretched by a hydraulic ram after which the nuts are run down and torqued by a wrench pulled by the dockside crane. The dynomometer on the crane is used to determine the torque loading of the nut. When the appropriate torque is reached the pressure on the ram is released and the nut is on to stay. This technique is used for critical components in other industries as well. Thanks for reminding me of stretched bolts.

[Toolmaker51]

Builders of high performance engines verify torquing of con-rod bolts in this way; measuring length before and after by micrometer. The calculations for effective torque are bound by diameter, thread pitch, and tensile strength.

[Trojan Horse]

Builders of high performance engines verify torquing of con-rod bolts in this way; measuring length before and after by micrometer. The calculations for effective torque are bound by diameter, thread pitch, and tensile strength.

Yes sir, I helped a cousin build his drag racing engine (BBC 632 CI & 1500 HP) and we used a specially built rod bolt stretch gauge to tighten the rod bolts.
I took one ride in it and that was enough for me.

[DIYer]

Thanks Rick! We've added your Nut Tightening Tool to our Fastening category, as well as to your builder page: Rick's Homemade Tools. Your receipt:

Nut Tightening Tool by Rick Sparber

tags: fasteners, hand tools

[kngtek]

Hi Rick,

Your posting on pretensioning of bolts brings back old memories which, although a bit off topic, somewhat relate. During the 1970's I worked for Union Carbide (now Dow Chemical) in their Montreal high pressure LDPE (low density polyethylene) plant, among other duties, as a design engineer in the associated compression/reaction/compounding processing units. The ethylene compressors & tubular reactors there operated up to 3000 bar (43,500 psi): the compressors in particular were massive in size with many flanged parts. Needless to say, these pressures far exceeded any ASME pressure flange/fitting standards I.e. greater than class 2500 (425 bar = 6164 psi) so we designed all our own flanges/fittings. Bolted flanges, in particular, were typically tightened using hydraulic bolt tensioners: a) to equalize the shared bolt load, and b) to allow minimum nut torquing as you describe in your posting.

Now I'm just happy to putz away making things on my micro lathe & mill.

Regards,

Gary (kngtek)
Calgary, AB

P.S. I enjoy all your homemadetools & website postings - lots to learn there.

[rgsparber]

Gary,

I can't imagine dealing with pressures that high. It must have been very satisfying to tame it.

Thanks for the story and kind words,

Rick