Toddler adjustable hand rail for stairs

This design is an adjustable handrail intended to be installed on stairways below existing adult sized handrails to enhance toddler safety.  

I created the design to address a lack of solutions available at the usual big box outlets.

Disclaimer* - The design has been tested & installed in my own home, but overall safety is ultimately dependent on the materials and skill of the individual performing the installation.  Please read the instructions below in their entirety and thoroughly test before use.  The end user is responsible to ensure compliance with local codes and regulations.  The end user assumes all liability.

General Details

The mounting assemblies are comprised of (4) components:

1. Channel Body

2. Post

3. Clamp

4. Retainers (2 per mounting assembly)

The printed parts should be minimum 6 walls @ 0.4mm nozzle, 0.2mm layer height and 20% infill (structural).  The parts were designed to be printed from PETG.   Tested on Core One.

Any warping will likely result in fit issues.  Bear this in mind when choosing material.

Note* For handrail clamps, I elected for a fixed rail angle for strength.  Mine is 43° but I have included separate files for angles between 35° and 45° in 2° increments.  You can measure your existing rail angle using your phone.

Heat set anchors are utilized for machine screws.  Confirm correct hole size appropriate for the inserts you are using as they may be different than mine (McMaster Carr).

Note*  Deep threads should be utilized for the posts (M5 screws).  The M4 screws on the retainers on the other hand are for retention only and can be shallow.

The counterbores have a sacrificial layer added to promote bridging without supports.  You can clear these with a drill bit.

Print Orientations:

Handrail:

The handrail is a Ø1.25" nominal (31.7mm) hardwood dowel (length as required).

The maximum span between supports must not exceed 36" (914mm).   Use as many mounts as required.

Installation:

1)  Level & affix each channel body on the wall at all 5 locations using #8 wood screws.  Confirm level prior to tightening.  Screws must be secured directly to studs, no anchors.

Height is as per discretion; but for reference, I installed the channel middle screw at 250mm below the centerline of the adult handhold.

2) Set the post location to the desired position.  Ensure the teeth are engaged and insert each retainer from either side.  The retainers should be snug fit but if they are too tight, an alternate version has been provided with looser tolerances.   

There should be minimal play in the assembly if the retainer fit is good.

Install M4 screws in each retainer to prevent loosening.  These do not need to be too tight.

3) Install the rail and once the position is confirmed, secure with #6 screws at each clamp.