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Buna O-Ring, 50A Durometer, Round, Black

Available in multiple versions

4.7 out of 5 stars 146 customer reviews

Price: $1.43 - $15.00
Product Specifications
Brand Name Small Parts
Material Type Nitrile Rubber
Hardness 50 A Durometer
System of Measurement Inch
Color Black
Cross Section Shape Round
LowerTemperature Range -30  Degrees Fahrenheit
Upper Temperature Range 250  Degrees Fahrenheit
Specification Met AS568A
Durometer 50a
UNSPSC Code 31410000

Currently showing 1-20 of 99 Next »
ASIN
The Amazon Standard Item Number (ASIN) uniquely identifies the item in the Amazon catalog.
Size Nominal Inside Diameter Nominal Outside Diameter Nominal Width Inside Diameter Outside Diameter Overall Width Number of Items Each Price Quantity
   
B0051XWWYI 004 0.07 inches 13/64 inches 0.07 inches 0.07 inches 13/64 inches 0.07 inches 100 $0.09 ea.
$9.00
B0051XWX0G 005 0.101 inches 7/32 inches 0.07 inches 0.101 inches 7/32 inches 0.07 inches 100 $0.10 ea.
$10.37
B0051XWX42 006 0.114 inches 1/4 inches 0.07 inches 0.114 inches 1/4 inches 0.07 inches 150 $0.07 ea.
$10.89
B0051XWX8S 007 0.145 inches 9/32 inches 0.07 inches 0.145 inches 9/32 inches 0.07 inches 125 $0.08 ea.
$10.39
B0051XWXCE 008 0.176 inches 5/16 inches 0.07 inches 0.176 inches 5/16 inches 0.07 inches 125 $0.05 ea.
$6.56
B0051XWXEC 009 0.208 inches 11/32 inches 0.07 inches 0.208 inches 11/32 inches 0.07 inches 125 $0.08 ea.
$9.40
B0051XWXGK 010 0.239 inches 3/8 inches 0.07 inches 0.239 inches 3/8 inches 0.07 inches 120 $0.08 ea.
$10.00
B0051XWXMY 011 0.301 inches 7/16 inches 0.07 inches 0.301 inches 7/16 inches 0.07 inches 115 $0.09 ea.
$9.97
B0051XWXOC 012 0.364 inches 1/2 inches 0.07 inches 0.364 inches 1/2 inches 0.07 inches 110 $0.09 ea.
$9.90
B0051XWXRE 013 0.426 inches 9/16 inches 0.07 inches 0.426 inches 9/16 inches 0.07 inches 90 $0.11 ea.
$9.60
B0051XWXVK 014 0.489 inches 5/8 inches 0.07 inches 0.489 inches 5/8 inches 0.07 inches 80 $0.11 ea.
$9.07
B0051XWXXS 015 0.551 inches 11/16 inches 0.07 inches 0.551 inches 11/16 inches 0.07 inches 80 $0.12 ea.
$9.85
B0051XWY00 016 0.614 inches 3/4 inches 0.07 inches 0.614 inches 3/4 inches 0.07 inches 75 $0.13 ea.
$9.50
B0051XWY1O 017 0.676 inches 13/16 inches 0.07 inches 0.676 inches 13/16 inches 0.07 inches 70 $0.15 ea.
$10.60
B0051XWY32 018 0.739 inches 7/8 inches 0.07 inches 0.739 inches 7/8 inches 0.07 inches 65 $0.16 ea.
$10.48
B0051XWY7S 019 0.801 inches 15/16 inches 0.07 inches 0.801 inches 15/16 inches 0.07 inches 60 $0.21 ea.
$12.75
B0051XWY8M 020 0.864 inches 1 inches 0.07 inches 0.864 inches 1 inches 0.07 inches 60 $0.17 ea.
$10.00
B0051XWY9Q 021 0.926 inches 1-1/16 inches 0.07 inches 0.926 inches 1-1/16 inches 0.07 inches 50 $0.21 ea.
$10.33
B0051XWYBE 024 1.114 inches 1-1/4 inches 0.07 inches 1.114 inches 1-1/4 inches 0.07 inches 45 $0.22 ea.
$10.00
B0051XWYEQ 027 1.301 inches 1-7/16 inches 0.07 inches 1.301 inches 1-7/16 inches 0.07 inches 35 $0.30 ea.
$10.34
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Product Features

  • Made of Buna-nitrile (also called Buna-N) for use with a variety of fluids from petroleum to aliphatic hydrocarbons
  • Durometer (hardness) of 50A for resistance to penetration
  • Round cross-section to provide a seal between cylindrical overlapping surfaces
  • For use across a wide temperature range from -30 degrees F/-34 degrees C to 250 degrees F/121 degrees C
  • Meets standards defined by Aerospace Standard AS568A

Product Description

This O-ring is made of black Buna-nitrile (Buna-N) and has a durometer of 50A. It has a round cross-section and can be used across a wide temperature range (-30 degrees F/-34 degrees C to 250 degrees F/121 degrees C). Designed for use in a wide variety of sealing applications, this Buna-nitrile O-ring meet standards defined by Aerospace Standard AS568A, which is the Aerospace Size Standard for O-rings.

Buna-nitrile can have high tensile strength, as well as abrasion, tear, and compression set resistance. It is compatible for use with petroleum, hexafluoroacetone (HFA), hexafluoro-2-butyne (HFB) and hydrofluorocarbon (HFC) fluids, vegetable oil, alcohol, acids, and aliphatic hydrocarbons. Buna-nitrile is vulnerable to acetone, ethers, esters, ozone, sunlight and weathering, and should not be used in ozone-generating electric motors, welding equipment, or in applications with exposure to UV light.

The durometer hardness of this Buna O-ring is 50A. Durometers measure the hardness of a material and its resistance to permanent indentation. A higher durometer value indicates greater resistance to indentation. On a scale of 0 to 100, a value of 0 indicates that a sample was completely penetrated, while a value of 100 shows no indentation in the sample. The letter following the number identifies the shore scale, which is either shore A or D. Shore A is used for softer plastics, while shore D is used for harder plastics.

O-rings provide a pressure and fluid seal between cylindrically shaped, overlapping mating surfaces and are commonly seen in engines, faucets, flanges, valves, and various cylinders. They are circular in shape, with a round cross section, and a hole in the center, similar to a doughnut. O-rings are available in various AS568A dash sizes, which is the standardized sizing for O-rings, and defines the nominal inside diameter (ID), outer diameter (OD), and cross-sectional (CS) diameter of an O-ring.


Product Details

  • Shipping Information: View shipping rates and policies
  • Domestic Shipping: Item can be shipped within U.S.
  • International Shipping: This item is not eligible for international shipping. Learn More
  • ASIN: B0052AU0HQ
  • Average Customer Review: 4.7 out of 5 stars  See all reviews (146 customer reviews)
  • Product Warranty: For warranty information about this product, please click here

Customer Questions & Answers

Customer Reviews

Top Customer Reviews

Size: 008Nominal Width: 0.07Overall Width: 0.07Outside Diameter: 5/16Inside Diameter: 0.176Nominal Inside Diameter: 0.176Number of Items: 125Nominal Outside Diameter: 5/16 Verified Purchase
I purchased this to modify my Cooler Master Quickfire Storm mechanical keyboard. The keyboard features Cherry MX blue keys, which make a clicky sound when depressed 2 mm. That click is not a problem, but if you push them down the full 4 mm, there is an additional clack that is quite loud and the abrupt stop is also a bit jarring to the hands. The right solution is to purchase O rings like this and install them on the bottom of every keytop. The 3/16" interior dimension version is what's wanted.

This is a pack of 125, which is perfect for a keyboard (you will have a few left over). They fit snugly and easily and had the desired effect: the bottoming out feels softer, is far quieter, and is less jarring on the hands. It also decreases the travel of the key. The difference is not huge, but it is noticeable to me. I also tried putting two of these on the bottom of some of the keys because I would like a really short travel keyboard. The result was an even softer, shorter travel stroke, but if you didn't hit it hard it didn't activate, so I had to remove them. You can really only use one of these per key.

I would be interested in thicker (same ID but larger OD) versions of these, and also the softer 40A hardness, which is very popular among keyboard modders. They are hard to find, though. The material is fine for the purpose (I don't think the pink stuff would be better in any meaningful way).

Anyway This is by far the cheapest and most convenient source of keyboard-modifying O rings that I have found, so I suggest them to anyone with a mechanical keyboard based on Cherry MX switches (which is almost all of them). Excellent product and price.

Thanks!
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Size: 008Nominal Width: 0.07Overall Width: 0.07Outside Diameter: 5/16Inside Diameter: 0.176Nominal Inside Diameter: 0.176Number of Items: 125Nominal Outside Diameter: 5/16 Verified Purchase
I got a Filco keyboard with Cherry MX Brown switches. I love the feel of the keyboard but it is a bit loud when the keys bottom out (hitting the plate). After reading a lot of positive reviews about modding the keys, I figured these were worth a try for the price.

I'm glad I did. The keyboard is now much quieter and noticeably softer to type on. In particular, I no longer worry about the noise that it makes that might bother my officemates. The one downside is that the keyboard now feels a bit less like a workout on the fingers. Overall, that's worth it for me, and worth trying if the noise bothers you at all.

Installation: there is not a lot of information here on exactly how the installation works. So I'll try to describe it; please supplement with videos from YouTube for more coverage. There are two primary parts to installation: removing and replacing the keys -- which is different for regular keys (most of them) vs. wide keys (space bar, enter, shift keys, backspace). The second part is putting the O-ring onto the key, and I'll start with that.

O-ring onto the key: when you turn the key over, you'll see a round column with a plus-sign shaped hole in it, in the center of the key. Just hold the o-ring on one side of the column and roll it over and onto the column. It will fit snugly. Press it down as far as possible with your fingers; it's not necessary to push it all the way down, but it may avoid problems if it's pushed down far enough to be slightly below the edge level. If a key doesn't activate well after reinstalling, just remove the key cap again (see below) and push the ring down a little more.

Keys on & off (regular keys): you'll want a
...Read more ›
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Size: 008Nominal Width: 0.07Overall Width: 0.07Outside Diameter: 5/16Inside Diameter: 0.176Nominal Inside Diameter: 0.176Number of Items: 125Nominal Outside Diameter: 5/16 Verified Purchase
This is by no means a bad product. As other reviews have mentioned, the improvement is very noticeable when you add the o-rings to your mechanical keyboard. I have two Razer blackwidow ultimate keyboards, the one with o-ring is much quieter, and you can slightly improve you typing speed due to the reduced key travel.

However, here is what you shall be aware of, backlit keyboard owners. The o-ring will block some of the light coming from the led, making letter partially lit and is definitely not very pleasing. If you are on the market for some o-rings, try transparent ones. Seems there is one type on amazon, but not sure whether it could improve backlighting. You may also find some on ebay, which ships from China.
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Size: 008Nominal Width: 0.07Overall Width: 0.07Outside Diameter: 5/16Inside Diameter: 0.176Nominal Inside Diameter: 0.176Number of Items: 125Nominal Outside Diameter: 5/16 Verified Purchase
These rings, as made evident in other reviews, are to help either quiet or lower the travel distance of a mechanical keyboard (or both). I put these on my full sized keyboard with cherry mx black switches.

You get the quoted amount in the package and none were made poorly or broken or anything. Each one fit on the key cap stem perfectly. Installing these is quite a breeze really as long as you make sure you read how to pull off a key with a stabilizer bar (space bar, enter keys, etc. have these). You get more than necessary for even a full sized board so if one does break or gets lost or falls between something you can't get, you're covered.

The value on these puppies is awesome. They are approximately half the price of other places - I suppose you could go cheaper and make your own but that seems so time consuming as to be absurd. Also, you can easily install these yourself so don't waste money on that - a mechanical keyboard is meant to be taken apart and put back together easily.

Edit 6/25/13 - This addition is to simply let you know that I've found another use for these in the computer world. I used them to dampen the sound/vibration on case fans for my computer. It's just wide enough to let the screw through and enough to thickness to help keep it marginally quieter. Given the pack I got had many extras, I put 1 of each of these wherever a screw and fan met in my case that I could. Just awesome.
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