Paragon repro of GM 272876 Marsden locking nut

[Gary B.]

Earlier today I went to install the new Marsden locking nuts that came in the Paragon engine mount to frame kit, Paragon 1921K. The nuts that came in that kit look like these:

4143FEDB-0E79-4011-9ABC-0DA6D13FB337.jpg

[Leif A.]

Re: Paragon repro of GM 272876 Marsden locking nut

From the Lok-Mor website:


MAR-LOC (Mardsen Type) All metal free running self-locking nut
* Materials: Steel grade *, alloys, and stainless stell
* Finish: Plain, zinc, and cadium, as well as other platings.

MAR-LOC (Marsden Type)

All metal free running self-locking nut.

• [*=left]Materials: Steel grade 8, alloys, and stainless steel
  [*=left]Finish: Plain, zinc, and cadmium, as well as other platings and coating

Gary,
Marsden nuts can be fairly loose when putting on.
Here's how they work.
If you will look at the face where they contact the mating "torque surface", you will see a small relief on the inner edge next to the threads.
When torqued down the force pulling on the threads pulls the inner portion of the nut down tending to bend that surface inward. This inward bend pulls the top slotted parts inwards against the threads thus providing the locking force.
So, to answer your question, yes, the locking feature of Mardsen nuts only happens when they are torqued...one time use only!!

[Gary B.]

Re: Paragon repro of GM 272876 Marsden locking nut

Leif,

You beat me to it. I just found that same webpage. Under the “free spinning” category of locking nuts. I didn’t know such things existed. I guess the Paragon nuts are fine.

So, does anyone know how free spinning or free running nuts provide a locking feature?

Gary

[Patrick H.]

Re: Paragon repro of GM 272876 Marsden locking nut

I assume (?) that the cut sides actually are placed "in" and the flat side is placed "out"?

[Joe L.]

Re: Paragon repro of GM 272876 Marsden locking nut

From the Lok-Mor website:


MAR-LOC (Mardsen Type) All metal free running self-locking nut
* Materials: Steel grade *, alloys, and stainless stell
* Finish: Plain, zinc, and cadium, as well as other platings.

MAR-LOC (Marsden Type)

...one time use only!!

Leif------

This is basically true for ALL nuts, locking or otherwise, and especially true for those in critical applications. Of course, for the sake of originality, a lot of these nuts are re-used, for better or for worse.

[Leif A.]

Re: Paragon repro of GM 272876 Marsden locking nut

Leif,

You beat me to it. I just found that same webpage. Under the “free spinning” category of locking nuts. I didn’t know such things existed. I guess the Paragon nuts are fine.

So, does anyone know how free spinning or free running nuts provide a locking feature?

Gary

Gary,
Did you read all the information I provided at the bottom of my original post? Your answer is there.

[Gary B.]

Re: Paragon repro of GM 272876 Marsden locking nut

Leif,

I was a bad student, and guilty of not reading the last part, thinking I already knew what was there. Thanks for pointing out the last part to me.

Gary

[Patrick H.]

Re: Paragon repro of GM 272876 Marsden locking nut

It still isn't entirely, at least to me, if the fingers go toward the object you are tightening (my assumption) or the flat side, no matter how many times I read the description or their website.

[Gary B.]

Re: Paragon repro of GM 272876 Marsden locking nut

It still isn't entirely, at least to me, if the fingers go toward the object you are tightening (my assumption) or the flat side, no matter how many times I read the description or their website.

2153419E-23E5-4FF3-BA68-39B53759EF8B.jpg

[Joseph S.]

Re: Paragon repro of GM 272876 Marsden locking nut

Joe, That's why Loctite is our NEW friend!!

[Michael G.]