Selecting cable railing hardware by diameter alone is incomplete. A reliable specification starts with two separate cable facts—diameter and construction—then adds the post material, stair or level geometry, and mounting method. MR.RAIL uses distinct model families for 1/8-inch, 5/32-inch, and 3/16-inch cable, so the model number is part of the compatibility decision.
A fitting that looks similar to another size is not an adjustable substitute. The cable, fitting and release tool must belong to the same size family. This guide maps the current MR.RAIL families without adding unconfirmed load ratings, span limits, code claims or package contents.
Start with cable diameter and cable construction
Cable diameter is the measured outside size of the wire rope. MR.RAIL standard families discussed here are 1/8 inch, 5/32 inch, and 3/16 inch. Confirm the actual diameter from the cable label, purchase record or approved project specification. Do not identify it only by looking at a photograph.
Cable construction describes how wires and strands are arranged. A 1/8-inch cable may be 1×19, 7×7 or another construction; the shared diameter does not make those cables interchangeable in a termination. MR.RAIL Quick Lock requires 1×19 cable. MR.RAIL Swage accepts matching-diameter 1×19 or 7×7 cable.
General industry references make the same distinction between diameter and construction. Lexco Cable describes 1×19 as a stiffer construction and 7×7 as more flexible, while also advising that fitting compatibility be confirmed for the actual wire rope and application (Lexco Cable). That general information does not replace the requirements for an MR.RAIL model.
How the three MR.RAIL size families are organized
The first digit changes with cable diameter, while the final digit keeps the application category aligned across the standard families. For example, MR-01, MR-11, and MR-21 are the wood-post stair-run Quick Lock category in three different sizes.
| Cable diameter | Quick Lock models | Swage model | Release tool |
|---|---|---|---|
| 1/8 inch | MR-01 through MR-06 | MR-08 | MR-09 |
| 5/32 inch | MR-11 through MR-16 | MR-18 | MR-19 |
| 3/16 inch | MR-21 through MR-26 | MR-28 | MR-29 |
There is no MR-17 or MR-27. The Hybrid configuration is not part of the standard 5/32-inch or 3/16-inch catalog. MR-07 is a customer-requested 1/8-inch configuration for 1×19 cable and should be discussed only when a project specifically asks for a Quick Lock end paired with a Swage end.
MR-09, MR-19, and MR-29 are release tools—not cable tensioners. Each release tool corresponds to its own cable-size family and is used for repositioning or cable removal from compatible Quick Lock hardware before final tensioning.
Match size and application at the same time
After identifying the diameter family, select the final digit from the post and run conditions. Wood-post and metal-post fittings use different attachment arrangements. Stair and angled runs also differ from level and straight runs. Through-post hardware adds another mounting decision.
| Application | 1/8 inch | 5/32 inch | 3/16 inch |
|---|---|---|---|
| Wood posts · Stair or angled runs | MR-01 | MR-11 | MR-21 |
| Wood posts · Level or straight runs | MR-02 | MR-12 | MR-22 |
| Metal posts · Stair or angled runs | MR-03 | MR-13 | MR-23 |
| Metal posts · Level or straight runs | MR-04 | MR-14 | MR-24 |
| Through-post · Stair or angled runs | MR-05 | MR-15 | MR-25 |
| Through-post · Level or straight runs | MR-06 | MR-16 | MR-26 |
| Surface-mount Swage · Wood posts | MR-08 | MR-18 | MR-28 |
| Quick Lock release tool | MR-09 | MR-19 | MR-29 |
Use the matrix as a selection route, not as an installation drawing. Hole preparation, threads, washers, tool sizes and access requirements remain model-specific and must follow the current approved instructions.
Wood-post Quick Lock families
MR-01 / MR-11 / MR-21 are for wood-post stair or angled runs. MR-02 / MR-12 / MR-22 are for wood-post level or straight runs. Both categories use matching-diameter 1×19 cable.
Metal-post Quick Lock families
MR-03 / MR-13 / MR-23 serve metal-post stair or angled runs. MR-04 / MR-14 / MR-24 serve metal-post level or straight runs. Confirm the prepared metal-post attachment specification rather than substituting a wood-post model.
Through-post Quick Lock families
MR-05 / MR-15 / MR-25 are the stair or angled through-post category. MR-06 / MR-16 / MR-26 are the level or straight through-post category. Rear access, cable path and the approved hole arrangement should be confirmed before installation begins.
Swage and release-tool families
MR-08 / MR-18 / MR-28 are surface-mount Swage cable hardware for wood-post level or stair runs. The matching Swage model can be used with 1×19 or 7×7 cable of the same diameter. MR-09 / MR-19 / MR-29 are the corresponding Quick Lock release tools.
Why 1×19 versus 7×7 still matters after choosing a size
Changing cable construction changes how the cable behaves and how it interfaces with a termination. For MR.RAIL, the compatibility rule is direct:
- Quick Lock: matching-diameter 1×19 cable only.
- Swage: matching-diameter 1×19 or 7×7 cable.
Do not use 7×7 cable in an MR.RAIL Quick Lock fitting. Do not assume that another manufacturer's fitting follows the same size range. Ultra-tec, for example, publishes its own product-specific diameter and construction rules for its 316 Stainless Steel cable and fittings (Ultra-tec). Those specifications demonstrate why brand-specific documentation matters, but they must not be used as MR.RAIL instructions.
A practical ordering workflow
- Record the cable diameter. Choose 1/8 inch, 5/32 inch, or 3/16 inch from a reliable label or specification.
- Record the cable construction. Confirm 1×19 or 7×7 rather than using the generic word “cable.”
- Identify the post material. Separate wood-post and metal-post runs.
- Separate stair and level runs. Count the required hardware for each geometry independently.
- Confirm the mounting arrangement. Decide whether the approved layout is surface-mount or through-post.
- Select the model family. Match both the application digit and the diameter digit.
- Confirm quantities and current instructions. Send drawings or photographs when the condition is unusual.
For distributor, wholesale, OEM or private-label inquiries, include the model-by-model quantity, packaging request, destination and any documentation requirements. Do not infer pricing, stock, MOQ or included tools from a general guide; confirm those details in the quotation.
Three size-selection mistakes to avoid
1. Ordering by product photo
Adjacent size families can look similar in a small image. Use the full model number and verified cable specification.
2. Treating diameter as construction
“1/8-inch cable” does not tell the supplier whether the cable is 1×19 or 7×7. State both facts.
3. Assuming one release tool fits every Quick Lock size
MR-09, MR-19, and MR-29 are separate, size-coded release tools. Choose the one that matches the Quick Lock family.
Frequently asked questions
Can one MR.RAIL fitting work with all three cable diameters?
No. The fittings are size-specific. Select the 01–09, 11–19 or 21–29 family as applicable, while observing the missing 17 and 27 model numbers.
Which cable construction works with MR.RAIL Quick Lock?
Matching-diameter 1×19 stainless steel cable only. Quick Lock does not accept 7×7 cable.
Which MR.RAIL products accept 7×7 cable?
The matching MR-08, MR-18 or MR-28 Swage family accepts 1×19 or 7×7 cable. Confirm the diameter before ordering.
Are MR-09, MR-19 and MR-29 tensioners?
No. They are release tools for the corresponding Quick Lock size family and are used before final tensioning.
Where are the installation manuals?
The existing MR-01 through MR-08 PDF links remain available in the Company Profile installation library. The files cover the matching standard diameter families as identified on that page.