Jump to content
I Forge Iron

Palnuts, and how to tighten them

Recommended Posts

I have seen these used in several applications but this is the first time I have seen the specs for proper application. Most likely it is something a blacksmith should know (grin).

Spin the palnut smooth face first onto the bolt until it touches the nut ( the six turned-up sides pointing away from the nut. Then tighten the palnut with a wrench one-quarter to one-half of a turn more to lock it.

Link to comment
Share on other sites

I am not familiar with this exact product but it seems to me that it is just a jam nut of sorts. by adding the second nut on top of the initial nut and then tightening it down. neither nut can move as they are jammed together. it is good for those times when you want to put a nut and bolt in a project without relying on the base structure to tighten and hold the nut and bolt together. essentially it it a mechanical version of locktite.

nice bit of info Glenn

Link to comment
Share on other sites

This torque spec was taken from a Reid engine manual.

palnuts are a double nut type locking system but the palnut is (as I recall) made from sheet metal and locks using tension on the threads. A bolt with a castle nut and a carter pin, or just a hole and hair pin, or a hole and a retaining wire, hold the nut in place but hot tight. I have seen a piece of metal spanning 2 bolts that you bent up the ears of the metal to keep the nuts from loosening. (350 cc BSA rear wheel - don't ask) . Lots of ways to mechanically keep nuts on bolts.

Palnut is a registered trademark of TransTechnology and is the most common name used for these stamped sheet metal check-nuts. They work in a very similar manner as a jam or checknut but their construction allows them to distort under load and return to their original shape in the threaded area because the are made form a spring like steel. They are also lighter than standard jam nuts. Be advised they are not a substitute for a positive locking device such as a castle nut and cotter pin or a corner drilled nut for safety wire.

Click here for photo
Palnuts provide a sound vibration proof locking action with minimum space requirements. Larger Palnuts provide locking actions on electricity pylons where frequent load changes would tend to loosen conventional Locknuts. Palnuts are low profile, and can be tightened with an internal wrench where a standard wrench is not suitable.

Palnut® has one of the most comprehensive lines of single thread, multi-thread, self threading and pushnut fasteners in the industry. Their product line consists of a full line of SAE standard and metric fasteners in a wide variety of sizes, strengths, designs and materials. Palnut® fasteners are used in place of more costly multi-fastener assemblies and are designed to reduce weight yet increase overall performance of the assembly.

Link to comment
Share on other sites

I saw these quite a bit in Army Land Combat Missile Systems that I worked on - Bradley Fighting Vehicles and APCs with the TOW missile systems, pre-ODS versions as well as on the first generation Dragon thermal night trackers. Good reliable and simple jam nut type system before locktite was very widespread.

Link to comment
Share on other sites

Those dumb things are also used on light duty high vibration items like body trim and engine air ducting.

I don't think highly of them, even though they do work well the first time. Take it apart and then try putting it back together and, in my experience, they don't work so good on reassembly.


Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...