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Hex Jam Nuts in 316 Stainless Steel
Marine Grade Thin Nuts For Locking Against Each Other
Jam nuts, also known aptly as thin nuts, are low profile hex nuts about 2/3rd the thickness of a standard hex finish nut. They are commonly used as a kind of locknut but may also be found in situations where a standard nut would not fit.
A jam nut is often used when a nut needs to be locked in place without clamping against another object. The jam nut essentially acts as the "other object," as the two nuts are tightened against each other. They can also be used to secure an item on a fastener without applying force to that object. This is achieved by first tightening one of the nuts onto the item. Then the other nut is screwed down on top of the first nut. The inner nut is then slackened back and tightened against the outer nut.
This locking action helps to avoid compression of the part being fastened while also locking it in place but still rotate freely, such as in bearings. The idea behind a jam nut is that a thin nut exerts less overall force than a fully torqued standard nut. They're the opposite of most heavy styles for nuts.
Stainless Steel
18-8 or 304 grades of Stainless steel are suitable for many general purpose applications, especially freshwater and non-salt water wet environments. For much more corrosive environments, such as in saltwater or marine applications, 316 stainless steel is the ideal choice. 316 Stainless steel is equivalent to A4 stainless steel.
| Nut Sizes | Flats | Thickness |
| 1/4" | 7/16" | 5/32" |
| 5/16" | 1/2" | 3/16" |
| 3/8" | 9/16" | 7/32" |
| 7/16" | 11/16" | 1/4" |
| 1/2" | 3/4" | 5/16" |
| 5/8" | 15/16" | 3/8" |
| 3/4" | 1-1/8" | 27/64" |
FAQs
What is a jam nut used for?
Jam nuts are low profile nuts commonly used as a type of locknut, where it is "jammed" up against another nut. With both nuts being fastened towards each other, this effectively locks the assembly in place. You may also find these nuts used in applications where a standard nut won't fit.
What is the jam nut method?
The jam nut method, sometimes known as the "double nut" method, is a friction locking method that uses two separate nuts fastened towards and against each other. Thus, the two nuts are bearing in opposite directions on the threads creating the "jam" effect.
How do you loosen jam nuts?
To loosen jam nuts, you can either take the outer nut off first and remove it like any other nut, or put a wrench on each nut and turn them in opposite directions to unfasten them from the assembly.
Why are jam nuts thinner?
Jam nuts are thinner because it helps save space when locking a pair of nuts together. The thinner size also means the jam nut exerts less overall force when fully torqued, so the standard nut can exert more force on the jam nut when they are fastened together without potentially damaging the material you're fastening to.
What does 316 mean for stainless steel?
316 is a grade of stainless steel under the 300 series of stainless steel, including 303, 304, and 305. 316 Stainless Steel is distinct from these other grades because it is highly corrosive resistant and well suited to marine applications.
Is 304 or 316 stainless better?
316 stainless steel is better in most ways over 304 stainless steel. 316 Stainless has excellent corrosion resistance, strength, and hardness and is well suited to marine applications. However, it's much more expensive than 304 and is not as formable as 304 either.
