3-Ring Letter Size Silver Binder Mechanisms with Locking Boosters [1-1/2" Slant D Ring] (150/Bx) (Discontinued)
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3-Ring Letter Size Silver Binder Mechanisms with Locking Boosters [1-1/2" Slant D Ring] (150/Bx) (Discontinued)

Sorry, but 3-Ring Letter Size Silver Binder Mechanisms with Locking Boosters [1-1/2" Slant D Ring] (150/Bx) (Discontinued) is no longer available to buy.

This item has been replaced with:
Item #: 113RBML112ADLB
Brand: Binding101
FAQ: 4 Questions, 4 Answers
  • To be used for an 11" binding edge
  • Locking boosters for extra durability
  • Compatible with standard 3 hole punches
Additional Sizes Below
Out of stock
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If you're looking for a ring binder spine, without any covers attached, then you have come to the right place. At Binding101 we stock several varieties of binder mechanisms. These particular ones are for letter size paper, which has an 11" binding edge (and are 8 ½" wide, though there is no limit to the sheet width you use with these loose ring binder parts). They have 3-rings with standard hole spacing of 4 ¼" between the rings, making them compatible with any standard letter hole puncher. You can choose from ring binder hardware with round or slant-d angled rings, as well as in either silver, a sleek matted black, or a vibrant brass color. On each end of the binder spine are boosters that assist with opening the rings, as well as rivet holes that allow you to bind them to any cover you see fit; just pair with rivets and a rivet setter tool for install. Ring binder mechanisms are a popular solution for making your own custom binders, unique display swatches, and much more.
Silver binder spines are the most common, and available in the most variety of ring sizes. You can choose from 1/2" up to 4" rings and, depending on the size, either round or slant-d ring styles. They are packaged with 50 mechanisms per box.
Black binder spines are a beautiful alternative, with a matted finish that really stands out. They are available in round ring sizes including 1/2", 1", or 1 ½". The packaged quantities varies depending on the size, so just select "black" and the ring size you want to see how many spine pieces there are per box.
Brass binder spines are a vibrant option that is a stunning gold color. They are available in round ring sizes including 1/2", 1", 1 ½", and 2". The box quantity varies depending on the size, select "brass" and the ring size you need to see the packaged quantity.
More detailed information, including ring capacities and specific spine measurements, can be found below.


Item #113RBML112ADLB
Sheet SizeLetter Size [8 ½" W x 11" H]
Number of Rings3-Rings
Ring ShapeSlant D Ring


Letter size ring binder mechanisms are the spine piece found on the inside of ring binders and work for 8 ½" x 11" standard letter sized papers. They feature 3-rings with traditional ring spacing of 4 ¼" between each ring, so work seamlessly with any traditional 3-hole punch. Use ring binder spines as a way to securely bind loose, hole-punched pages, or as a unique way to create swatch books and custom ring binders. You can pair with our binder rivets and rivet setter tool to bind the ring binder hardware onto a custom chip board sheet.

These metal binder parts are available in three colors: silver, black, and brass. Traditional silver binder mechanisms are available in the full range of ring sizes from 1/2" up to 4", many of those sizes also available in either round ring or slant-d ring options. They offer the most versatility, and are our most popular option because of their traditional and clean look, as well as their packaging with 50 mechanisms per box. Black and brass colored binder mechanisms are available in select sizes from 1/2" to 2", all with round ring styles. The packaging for colored ring binder spines varies depending on the ring size, but all you have to do is make a selection above to see the quantity per box. All colors are made of a durable metal material, and feature two boosters for easy ring opening and closing, as well as holes on each end that allow use with our binder rivets for binding the spine onto an item of your choice.

Ring Capacities:

In the following chart we outline the various ring sizes available, the color options for each size, and both the speed capacities and stack capacities. The stack capacity will always be the most accurate way to determine the correct ring size for you, as it allows for variances in paper stock, the additions of index tabs, etc. For example, a 1" stack of 20 lb. paper will always be the same thickness as a 1" stack of 110 lb. index stock. Whereas the sheet capacity is based solely on 20 lb. bond copy paper.

Ring SizeColors AvailableSheet Capacity*Stack Capacity*
1/2"Silver & Black110 Sheets1/4" Thick Stack
3/4"Silver & Brass150 Sheets3/8" Thick Stack
1"Silver, Black, & Brass200 Sheets5/8" Thick Stack
1 ½"Silver, Black, & Brass310 Sheets1" Thick Stack
2"Silver & Brass450 Sheets1 ½" Thick Stack
2 ½"Silver540 Sheets2" Thick Stack
3"Silver650 Sheets2 ½" Thick Stack
4"Silver850 Sheets3 ½" Thick Stack

Binder Spine Measurements:

As the ring diameter changes, so do some of the overall spine piece measurements. This chart outlines those dimensions for each size of ring, as well as round and slant-d options. Note that these measurements are estimates and may have a slight variance.

Ring SizeRing ShapeBase LengthBase WidthRing SpacingRivet Hole PositionRivet Hole SpacingRivet Hole Diameter
1/2"Round11 ¼"13/16"4 ¼" (Center to Center)3/4" in from Short End9 ½" Center to Center3/16"
3/4"Round11 ¼"13/16"4 ¼" (Center to Center)3/4" in from Short End9 ½" Center to Center3/16"
1"Round11 ¼"1”4 ¼" (Center to Center)3/4" in from Short End9 ½" Center to Center3/16"
1 ½"Round11 ¼"1 ⅛”4 ¼" (Center to Center)3/4" in from Short End9 ½" Center to Center3/16"
Slant-D11 ⅜"
2"Round11 ¼"1 ⅜”4 ¼" (Center to Center)3/4" in from Short End9 ½" Center to Center3/16"
Slant-D11 ⅜"1 ⁷/₁₆”
2 ½"Round11 ¼"1 ⅜”4 ¼" (Center to Center)3/4" in from Short End9 ½" Center to Center3/16"
Slant-D11 ⅜"1 ⁷/₁₆”
3"Round11 ¼"1 ⁷/₁₆”4 ¼" (Center to Center)3/4" in from Short End9 ½" Center to Center3/16"
Slant-D11 ⅜"
4"Slant-D11 ⅜"1 ¾”4 ¼" (Center to Center)3/4" in from Short End9 ½" Center to Center3/16"

* Sheet capacity is an approximation based on standard 20 lb. bond copy paper, and may vary depending on paper stock being used. Stack capacity is a more accurate alternative. To measure, place your entire stack of material on a flat surface and, without pressing the stack down, measure the thickness of the stack.


Letter Size Ring Binder Mechanism Spines - Colors, Sizes, & Options Available

How to Attach Binder Mechanisms to Covers

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You're reviewing:3-Ring Letter Size Silver Binder Mechanisms (Price per Box) - Limited Stock Available While Supplies Last (Discotninued)
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Expert Reviews

Expert Reviewer: Mallory, Editor at Binding101Expert Product Review: 3-Ring Binder Mechanisms  by Mallory Morsa
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Hi everyone! My name is Mallory Morsa, and I am the product expert at Binding101. I have been a part of the Binding101 team since 2008, where I started out in service and sales, learning our customers' needs and how to offer truly exceptional service. After a of couple years, I moved into a role of product management that required in-depth product research, as well as training of our staff. And in my honest expert reviews, I am proud to share that extensive knowledge with you. Take a look at the product review below, which will highlight both the pros and the cons, as well as identify the ideal customer. If you have any questions or need more information, please call our customer care team at (866)537-2244. Thank you for stopping by, and please check out our Binding101 social media channels by clicking the icons above.


Metal Binder Mechanism + 3-Ring Binder Parts Expert Review by Mallory Morsa


Binder mechanisms are popular for users of many kinds who want to make their own ring binders. Because they are sold in full boxes of 50+ mechanisms (depending on the size/color) our customers tend to be in the manufacturing, industrial supply, and government/military industries, however, sometimes home businesses that make custom binders to sell on Etsy will buy too. They are even used by furniture and fabric stores to hold swatches of fabrics as an alternative to loose leaf rings.

Binder mechanisms are great, because they give you complete control over making your own custom binder and other crafts. They are made of metal, and are very durable to withstand a lot of heavy use. They have boosters on the ends, which make opening the rings quick so you don’t have to pull the rings open by hand, and there are two holes in each mechanism for rivets, which when bound properly, will make a very strong attachment. They also come in several colors, so you can make your binders stand-out with gold/brass or black mechanisms, or keep a more traditional look with the silver ones.

These particular ring mechanisms are letter size, which is the most popular ring binder size in the US. The spacing is regular 3-ring spacing to be compatible with all standard 3-hole punches (like the ones available here). And because they are just the metal binder spine without the covers attached, they are extremely versatile. Use them to make traditional ring binders or unique clipboards, or use them to  hang calendars and organize items, or for anything else that you can think of. The pricing is also very reasonable per piece (especially the silver, considering you can probably not find them elsewhere for under $5 each), part of the benefit of selling full-case quantities.

There is a minimum order requirement for these mechanisms that makes them unobtainable by a lot of individuals or personal users, and even some small businesses. For silver mechanisms, it is 50 pieces for all the sizes. For black and brass mechanisms, the quantity varies depending on the ring size, ranging from 54 to 200 pieces. Unfortunately, we are unable to sell smaller quantity boxes, as these minimums are required by the manufacturer. They are also not available in assorted size boxes, so if you need 1" and 2" silver mechanisms, the minimum is 1 box per size.

Unless you have a large, automatic rivet setter machine for your industrial manufacturing plant, then riveting is done using a hand setter tool that can sometimes be tedious and difficult to use without the proper amount of strength. I am a fairly small woman, and it took several tries before I was able to accomplish a good finish that was tight enough to hold the mechanism in place properly. So before you buy, consider the fact that it can take quite a bit of effort and strength to rivet them to your binder covers and other materials, and consider standard pre-made ring binders as an alternative.

Also, although 3 colors are available, only silver is available in the full range of ring sizes from ½” to 4”, as well as round-ring and slant-d ring styles; the black and brass colors are only available with rings up to 2” in the round-ring style.

Ring binder mechanisms are a popular solution for businesses of many kinds, especially industrial and manufacturing plants, as well as government/military bases, and more. They are the standard size for the most popular paper size in the United States (8 ½” x 11”), come in a few cool colors, and several different ring sizes to handle stacks of paper and other materials up to 3 ½" thick. They are only sold in case-quantities (starting at 50 per case) and are unavailable in smaller boxes. Sometimes they can be a challenge to work with, but if you persevere, you can create a huge variety of unique ring binders and other items of all kinds.

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