We're here to help.



Use with soft or hardwood posts


Use with vinyl or composite post sleeves


Use with Signature series or custom metal posts


Use with structural masonry posts or columns


Aluminum posts, matching handrail, and stainless steel cable railing.

Shop >

All stainless integrated post and tensioning cable railing.

Shop >

How to install cable rail kits in wood, metal, or masonry posts.

Browse Guides >

How to install Signature series posts, handrail, and cable infill.

Browse Guides >

How to install Venture series posts, handrail, and cable infill.

Browse Guides >

This section doesn’t currently include any content. Add content to this section using the sidebar.

Image caption appears here

Add your deal, information or promotional text

This section doesn’t currently include any content. Add content to this section using the sidebar.

Image caption appears here

Add your deal, information or promotional text

Splines for Reinforced Aluminum Handrail


Free shipping on orders over $1,499* Details >

376 in Stock - Ships in 1-3 business days

Clean, Concealed Joints for your Aluminum Handrail

Join your aluminum handrail sections using a combination of fixed and adjustable splines. Once installed, all splines are concealed giving your handrail and clean, continuous look free of brackets or cover plates. Furthermore, each aluminum spline creates a structural joint that does not need to be supported by a post, allowing you to span further with fewer posts.

The following splines are designed exclusively for Cable Bullet reinforced aluminum handrail.

Continue Reading >

Structural, Fixed or Flexible Options for Any Handrail Configuration

Fixed Splines

Fixed splines are available for level, 90-degree corner transitions, as well as straight runs. For irregular or custom bends in your railing, spline stock can be used to create any transition.

Fixed Straight Spline (Structural Aluminum)

Use these 4-inch long structural aluminum splines to quickly piece together two or more lengths of a handrail along a straight run to create a structural joint. Joints using the structural aluminum spline do not need to be supported over a post! This allows you to join pieces of handrail to form one continuous run without needing to worry about the placement of your structural support posts, reducing waste and time spent cutting custom lengths.

In combination with our reinforced aluminum handrail, these splines allow you to extend your structural post spacing 7-9 feet apart with minimal deflection under load.

Fixed Corner Spline

The fixed corner spline is made from Delrin, weather and UV-resistant exterior-grade plastic, and is designed for use at any level, supported corner transition. All Delrin splines are slightly oversized by design and may require a rubber mallet or dead-blow hammer to set in place.

18-Inch Spline Stock

Delrin plastic spline stock is available in 18-inch sticks and is intended to be cut down on-site and modified to create any non-standard, horizontal transition, e.g. a 45-degree turn in your railing. Use a miter saw and deck screws as needed. One 18-inch stick is sufficient material to make up to 3 splines. Any custom Delrin spline should be supported by a structural post. Use 2-1/2-inch #9 decking screws to connect spline pieces.

Adjustable Splines

Adjustable splines are designed to simplify handrail construction around stairs, and complex angles or transition points. Use adjustable splines anywhere your handrail breaks from a level to an angled run or makes a horizontal non-90-degree transition. Each spline will pivot to match the rise of your stairs or horizontal angle.

Adjustable Spline Options:

  1. Adjustable straight splines include two interlocking end pieces that pivot on a hinge pin. This spline can be used anywhere a level straight run continues into an angled run, or where a stair handrail levels out.
  2. Vertical corner splines have two additional lap joints that form a corner piece. Use this spline on inside corners around stairs and landings.
  3. Horizontal corner splines have a central lap joint that allows the end pieces to pivot on a horizontal plane. Use this spline on any non-90-degree level turn. 
  4. 180-degree splines include two end pieces and four lap-joints to create a u-shaped spline. This spline is designed for handrail connection points that require two pivot points, e.g. on the inside railing between two flights of stairs connected by a landing.

All aluminum splines are machined from heavy-duty type 6061 aluminum. Use the #8 x 3/4" stainless steel sheet metal screws included with the spline to secure it through the underside of your handrail.