Hi everyone,

I'm hoping someone having experience with self locking nuts can help
me with the following.

At mcmaster.com I found four types of self locking nuts I can use on a
1/4-28 thread bolt. I just want to snug the nut down on the bolt to
take up any linear or axial play, but I'm not going to really torque
the nut down with any significant force. I could use loc-tite to keep
the nut from backing off but I want to try a self locking nut.

I have listed my choices from www.mcmaster.com below. I need to know
which nut will provide the most resistance to removal with a wrench.
There are no vibrations or anything in the application, I just need to
know which self locking method will provide the most resistance to
removal with a standard wrench. The nut will never be removed or
reused after it's snugged down.

If you could also list them in order of most resistance to least
resistance that would be great. If you are aware of any information or
online reference for actual forces required to loosen the nuts, that
would also be very helpful.

90566A210 (Nylon insert type Lock nut)
94830A515 (Expanding type lock nut)
91837A250 (Distorted thread type lock nut, top-lock style)
90040A120 (Distorted thread type lock nut, center-lock style)

I would appreciate any feedback or experiences with self locking nuts.

Thanks
John

I would appreciate any feedback or experiences with self locking nuts.

Thanks
John

John

Even simpler. Get two jam nuts from your friendly hardware store and
jam them together. Maybe a washer between them if you like.

Bob AZ

On Thu, 24 Jul 2008 17:44:24 -0700 (PDT), John2005
wrote:

Hi everyone,

I'm hoping someone having experience with self locking nuts can help
me with the following.

At mcmaster.com I found four types of self locking nuts I can use on a
1/4-28 thread bolt. I just want to snug the nut down on the bolt to
take up any linear or axial play, but I'm not going to really torque
the nut down with any significant force. I could use loc-tite to keep
the nut from backing off but I want to try a self locking nut.

I have listed my choices from www.mcmaster.com below. I need to know
which nut will provide the most resistance to removal with a wrench.
There are no vibrations or anything in the application, I just need to
know which self locking method will provide the most resistance to
removal with a standard wrench. The nut will never be removed or
reused after it's snugged down.

If you could also list them in order of most resistance to least
resistance that would be great. If you are aware of any information or
online reference for actual forces required to loosen the nuts, that
would also be very helpful.

90566A210 (Nylon insert type Lock nut)
94830A515 (Expanding type lock nut)
91837A250 (Distorted thread type lock nut, top-lock style)
90040A120 (Distorted thread type lock nut, center-lock style)

I would appreciate any feedback or experiences with self locking nuts.

Thanks
John

in aviation we use the first and third types.
I find that the third type has a stronger hold than a nylock.

look up 'Nord-Lock' on google. this is a little double washer that
sits under the nut. it has stepped faces that make the release force
of the nut higher than the forced used to snug down the nut.
it may be a way of achieveing what you want. you could use plain nuts
or nylocks with them.

Stealth Pilot

Stealth Pilot missed the REAL thing we use in aviation when we don't want
the nut to come off, it's called "saftey wire"

It's also pretty tough to get a castle nut to move when it's got a cotter
key through it.

If you are serious about NEVER removing this nut try some "Locktite" and in
a pinch "crazy glue" works well too... FTI "crazy glue" can be rendered
useless by heating it.

--.- Dave (who takes the C-182 down this weekend for it's "annual")


"John2005" wrote in message
...
Hi everyone,

I'm hoping someone having experience with self locking nuts can help
me with the following.

At mcmaster.com I found four types of self locking nuts I can use on a
1/4-28 thread bolt. I just want to snug the nut down on the bolt to
take up any linear or axial play, but I'm not going to really torque
the nut down with any significant force. I could use loc-tite to keep
the nut from backing off but I want to try a self locking nut.

I have listed my choices from www.mcmaster.com below. I need to know
which nut will provide the most resistance to removal with a wrench.
There are no vibrations or anything in the application, I just need to
know which self locking method will provide the most resistance to
removal with a standard wrench. The nut will never be removed or
reused after it's snugged down.

If you could also list them in order of most resistance to least
resistance that would be great. If you are aware of any information or
online reference for actual forces required to loosen the nuts, that
would also be very helpful.

90566A210 (Nylon insert type Lock nut)
94830A515 (Expanding type lock nut)
91837A250 (Distorted thread type lock nut, top-lock style)
90040A120 (Distorted thread type lock nut, center-lock style)

I would appreciate any feedback or experiences with self locking nuts.

Thanks
John

On Jul 24, 6:44*pm, John2005 wrote:
Hi everyone,

I'm hoping someone having experience with self locking nuts can help
me with the following.

At mcmaster.com I found four types of self locking nuts I can use on a
1/4-28 thread bolt. I just want to snug the nut down on the bolt to
take up any linear or axial play, but I'm not going to really torque
the nut down with any significant force. I could use loc-tite to keep
the nut from backing off but I want to try a self locking nut.

I have listed my choices fromwww.mcmaster.combelow. I need to know
which nut will provide the most resistance to removal with a wrench.
There are no vibrations or anything in the application, I just need to
know which self locking method will provide the most resistance to
removal with a standard wrench. The nut will never be removed or
reused after it's snugged down.

*If you could also list them in order of most resistance to least
resistance that would be great. If you are aware of any information or
online reference for actual forces required to loosen the nuts, that
would also be very helpful.

90566A210 *(Nylon insert type Lock nut)
94830A515 * (Expanding type lock nut)
91837A250 * (Distorted thread type lock nut, top-lock style)
90040A120 *(Distorted thread type lock nut, center-lock style)

I would appreciate any feedback or experiences with self locking nuts.

Thanks
John

If you want it NEVER to move again, use the permanent grade of
Loctite. Much cheaper than messing with any sort of self-locking nut
and lots easier to get on, too. Only way to get it off is to heat the
nut with a torch till it smokes. Used a lot of it on VW air-cooled
flywheel gland bolts.

Stan

in aviation we use the first and third types.
I find that the third type has a stronger hold than a nylock.
Stealth Pilot- Hide quoted text -

- Show quoted text -

Speaking of aviation. Where does one find the nuts that can be "wire
nutted" to the bolt. A shop where I do work needs some.

Bob AZ

If I use a regular non hardened hex nut (maybe a grade 2 or a brass
nut) could I tap a hole through the side (through one of the nut flats
to the center of the nut) that would allow me to use a cone point set
screw to lock the nut in place after it's snugged down, or would
tapping the nut in this way mess up the nut threads so that it would
not thread onto the bolt ?

If it could work, tapping the nut would be easy and set screws are
cheap. Plus I would save time cleaning the bolts, applying primer, and
waiting for the loc-tite to dry.

Once the cone point set screw digs in, I don't think it would go
anywhere. It's just a matter of whether it can be done without messing
up the nut threads.

Do you think it would likely work ?

On Fri, 25 Jul 2008 09:16:25 -0700 (PDT), Bob AZ
wrote:


in aviation we use the first and third types.
I find that the third type has a stronger hold than a nylock.
Stealth Pilot- Hide quoted text -

- Show quoted text -

Speaking of aviation. Where does one find the nuts that can be "wire
nutted" to the bolt. A shop where I do work needs some.

Bob AZ

the term is "lockwired" I've never heard of 'wire nutted'.

what is more often used is a castellated nut with a split pin through
a hole in the bolt. this is used on hinge bolts.

what I think you are referring to is a hexagon nut is drilled through
the peak of the hex from flat to flat. I have no idea how they
actually do it without breaking drills.
it appears to me to be the most difficult drilling I could imagine
although thinking about it all the nuts done this way are brass so
maybe it is easy with a jig.

what is often done is not to bother changing the nut but to create a
washer with a lobe. the lobe has a hole through it and is bent up
clear of the underlying surface. the lobe is lockwired to something.
on the washer you bend a section or two up onto the flat of the bolt.
something like this is used on marvel schebler carburettor bodies.

there is also the method used on a glider I know. the counter weight
is screwed on to a support. both pieces have opposite side flats.
a washer is used between them. one side is bent up, the other side
bent down.

if none of these work for you describe the application more fully and
I'll try again.

Stealth Pilot

On Fri, 25 Jul 2008 08:44:12 -0700, "Dave August"
wrote:

I just need to
know which self locking method will provide the most resistance to
removal with a standard wrench. The nut will never be removed or
reused after it's snugged down.

of course dave but the quoted part above is a description of what
Nord-Locks do best.

a round nut with no flats could do this perfectly.

On Sat, 26 Jul 2008 23:37:34 +0800, Stealth Pilot
wrote:
snip
it appears to me to be the most difficult drilling I could imagine
although thinking about it all the nuts done this way are brass so
maybe it is easy with a jig.
snip
========
common on race vehicles. jigs are commercially available.

see
http://www.pitposse.com/9sawipl.html
http://www.solomotoparts.com/catalog...g-p-22650.html
http://pitposse.stores.yahoo.net/nutdrilljig.html
and many others. for OTC purchase try your local motorcycle
shop.


Unka' George [George McDuffee]
-------------------------------------------
He that will not apply new remedies,
must expect new evils:
for Time is the greatest innovator: and
if Time, of course, alter things to the worse,
and wisdom and counsel shall not alter them to the better,
what shall be the end?

Francis Bacon (1561-1626), English philosopher, essayist, statesman.
Essays, "Of Innovations" (1597-1625).

Stealth Pilot wrote:
On Fri, 25 Jul 2008 09:16:25 -0700 (PDT), Bob AZ
wrote:

in aviation we use the first and third types.
I find that the third type has a stronger hold than a nylock.
Stealth Pilot- Hide quoted text -

- Show quoted text -
Speaking of aviation. Where does one find the nuts that can be "wire
nutted" to the bolt. A shop where I do work needs some.

Bob AZ

the term is "lockwired" I've never heard of 'wire nutted'.

what is more often used is a castellated nut with a split pin through
a hole in the bolt. this is used on hinge bolts.

what I think you are referring to is a hexagon nut is drilled through
the peak of the hex from flat to flat. I have no idea how they
actually do it without breaking drills.
it appears to me to be the most difficult drilling I could imagine
although thinking about it all the nuts done this way are brass so
maybe it is easy with a jig.

what is often done is not to bother changing the nut but to create a
washer with a lobe. the lobe has a hole through it and is bent up
clear of the underlying surface. the lobe is lockwired to something.
on the washer you bend a section or two up onto the flat of the bolt.
something like this is used on marvel schebler carburettor bodies.

there is also the method used on a glider I know. the counter weight
is screwed on to a support. both pieces have opposite side flats.
a washer is used between them. one side is bent up, the other side
bent down.

if none of these work for you describe the application more fully and
I'll try again.

Stealth Pilot

There are also castellated locks for standard nuts. They go over the
existing nut and get pinned or wired in place. Used to see them a lot on
front wheel bearings.

Of course if the OP actually means that once installed he will REALLY
never need to remove it. Tack it with a welder.

--
Steve W.
Near Cooperstown, New York

Thanks for the additional replies guys, and thanks for the links to
that nut fixture F. George Mcduffee.

Tacking with a welder may be an option at some point. I could drill
through both the nut and bolt after assembly and put a roll or spring
pin in there, but something about doing this after the unit is already
assembled did not appeal to me.

If I use a set screw in the nut as mentioned above, can I drill and
tap the nut for a set screw before it's threaded onto the bolt, or
will I have no choice but to do it after assembly (I'm thinking the
cris-crossed taps might cause a problem with threading the nut onto
the bolt) ? If I have to do it after assembly then a roll pin would be
better.

It could be that a standard locking nut will work. The nut and bolt
rotate together as one unit as the bolt is rotated to adjust a slider.
There is not much axial force on the bolt during adjustment but the
loads increase when the device is in use. There is a Delrin washer
under the nut so as long as the friction between whatever is locking
the nut to the bolt is greater than the friction between the nut and
the delrin washer due to bolt rotation, then the nut should never back
off. It would only tend to back off in one direction of rotation
anyway as the other direction would tend to tighten the nut. If I have
to use a steel washer at some point, then I may need a stronger bond
between the nut and bolt but even then it seems a locking nut may
work.

It seems that the consensus is that the distorted thread type lock
nuts have the greatest resistance to removal.

John

On Sat, 26 Jul 2008 14:08:18 -0700 (PDT), John2005
wrote:

Thanks for the additional replies guys, and thanks for the links to
that nut fixture F. George Mcduffee.

Tacking with a welder may be an option at some point. I could drill
through both the nut and bolt after assembly and put a roll or spring
pin in there, but something about doing this after the unit is already
assembled did not appeal to me.

If I use a set screw in the nut as mentioned above, can I drill and
tap the nut for a set screw before it's threaded onto the bolt, or
will I have no choice but to do it after assembly (I'm thinking the
cris-crossed taps might cause a problem with threading the nut onto
the bolt) ? If I have to do it after assembly then a roll pin would be
better.

It could be that a standard locking nut will work. The nut and bolt
rotate together as one unit as the bolt is rotated to adjust a slider.
There is not much axial force on the bolt during adjustment but the
loads increase when the device is in use. There is a Delrin washer
under the nut so as long as the friction between whatever is locking
the nut to the bolt is greater than the friction between the nut and
the delrin washer due to bolt rotation, then the nut should never back
off. It would only tend to back off in one direction of rotation
anyway as the other direction would tend to tighten the nut. If I have
to use a steel washer at some point, then I may need a stronger bond
between the nut and bolt but even then it seems a locking nut may
work.

It seems that the consensus is that the distorted thread type lock
nuts have the greatest resistance to removal.

John

I agree.

in aviation practise a bolt which forms a pivot is always used with a
castellated nut with a split pin. ...thats the mantra.

on my tailwheel is a link rod with two ball ends. since these pivot I
used castellated nuts, drilled bolts and splitpins. ...and needed to
replace them about 4 times a year. the threads were forever stripping
out.

I replaced the bolts with undrilled bolts and used deformed thread
nuts (they are an aviation nut for application in areas subject to
heat that would melt the nylock). it turns out that these nuts have
over twice the thread length in them in comparison to nylocks or
castellated nuts. in 4 years I've never had to touch or replace them
once.

the mantra isnt always correct.

btw you will get best results using them dry.
Stealth Pilot

"Dave August" wrote in message
...
Stealth Pilot missed the REAL thing we use in aviation when we don't want
the nut to come off, it's called "saftey wire"


There are those of us in aviation design that feel saftey wire only holds
the broken parts together. I can show pretty easily that the tangent load
associated with the torque to remove a nut is much grater than the tensile
strength of the wire. My feeling is that if there is enough energy in the
system to make the nut back off (vibration, rotation frictions, etc.) then
there is more than enough energy to break the wire.

The FARs require any bolt in flight control systems which is subject to
rotation to be retained with at least two means of retention, one of which
must not be friction. Practically, this usually means a castilated nut and
cotter pin. The problem with this arrangement is that by definition you
loose the primary retention method of the design - namely the tensioning of
the bolt-nut assembly to near it's yeild strength.

If possible you are always better off revising the design to ensure the bolt
is not subject to rotation and then use the deformed thread self locking nut
for the secondary means of retention.

my $.02

For what you seem to want to do, best options (decreasing security,
increasing ease)

Weld it.

Braze it.

Solder it.

Use the SERIOUS Loctite on it. Back in the 1980's that was "red" .vs.
"blue" but they have many more products now - but they presumably still
make several that are really, REALLY difficult to remove, requiring
heat, etc. - use one of those.

Lock nuts don't compare favorably in effectiveness.

--
Cats, coffee, chocolate...vices to live by

--Um, here's another approach: http://www.nmpproducts.com/nmp06.htm
--A buddy of mine makes these; his site's at www.venturahobbies.com


--
"Steamboat Ed" Haas : "Hold on! we're passing
Hacking the Trailing Edge! : through the moronosphere!"
www.nmpproducts.com
---Decks a-wash in a sea of words---

On Thu, 24 Jul 2008 17:44:24 -0700 (PDT) in rec.crafts.metalworking,
John2005 wrote,
There are no vibrations or anything in the application, I just need to
know which self locking method will provide the most resistance to
removal with a standard wrench. The nut will never be removed or
reused after it's snugged down.

Ordinary nut. Leave about 1/2 bolt diameter sticking out past the
nut or cut it off at that length. Peen over the bolt end with a ball
peen hammer to form a round rivet head. No wrench is gonna take that
off.

On Thu, 24 Jul 2008 17:44:24 -0700 (PDT), with neither quill nor
qualm, John2005 quickly quoth:

Hi everyone,

I'm hoping someone having experience with self locking nuts can help
me with the following.

At mcmaster.com I found four types of self locking nuts I can use on a
1/4-28 thread bolt. I just want to snug the nut down on the bolt to
take up any linear or axial play, but I'm not going to really torque
the nut down with any significant force. I could use loc-tite to keep
the nut from backing off but I want to try a self locking nut.

I have listed my choices from www.mcmaster.com below. I need to know
which nut will provide the most resistance to removal with a wrench.
There are no vibrations or anything in the application, I just need to
know which self locking method will provide the most resistance to
removal with a standard wrench. The nut will never be removed or
reused after it's snugged down.

If you could also list them in order of most resistance to least
resistance that would be great. If you are aware of any information or
online reference for actual forces required to loosen the nuts, that
would also be very helpful.

90566A210 (Nylon insert type Lock nut)
94830A515 (Expanding type lock nut)
91837A250 (Distorted thread type lock nut, top-lock style)
90040A120 (Distorted thread type lock nut, center-lock style)

I would appreciate any feedback or experiences with self locking nuts.

In my experience, the nylock nuts (#1 in your list) are destroyed by
running them more than about one thread's worth past the nylon. They
work fine on the far end of a thread only.

Top/center-distorted nuts (#3,4) provide some extra oomph, but also
wear down if they're run very far down the thread.

Expanding head locknuts (#2) don't wear out as quickly as the top two
but also don't hold as tightly.

None of the above put up any real resistance at _all_ to removal with
a standard wrench. I won't use the top two at all in automotive work
and am amazed that the aircraft industry allows them (expanding the
thought behind Stealth Pilot's reply to you.)

If you want easy installation in addition to moderate resistance to
wrench removal, use a blue Loctite like #246. (See McMaster catalog
page 3326) It takes a concerted effort to remove or change a Loctited
nut's position.

If you want easy installation in addition to severe resistance to
wrench removal, use a red Loctite like #262. (same page) It takes
_heat_ and tools to remove a nut.


IOW, if a wrench is involved, none of the four you discussed is worth
a hoot.

If it were vibration you were worried about, a friend who owned and
raced a Husky 400 motorcycle used Loctite on it. That bike was so
powerful and vibratory, even the blue Loctite failed. Only the red
worked for him. I rode that jet once and it scared the **** out of me.
The throttle was damnear a toggle switch with a jet engine connected
to it. I pinched several buttonholes in my skivvies before I got the
reversed throttle turned the correct direction and got my feet back on
the bike. It was some heavy metal, man. g

--
Imagination is more important than knowledge...
Albert Einstein (1879 - 1955)