Curtain Track Stop Block

This is an adjustable stop block for ceiling mounted curtain track trolleys.

We recently installed three sections of ceiling mounted curtain tracks in a bay window alcove.  The three track sections are mitered and the curtain trolleys can traverse across the miters. There are four curtain panels.

A problem arose when closing the curtains. The trolleys move very freely in the tracks and there is a tendency for one or two of the endmost trolleys at the stationary ends of each curtain panel to move out of position when pulling them closed.

These stop blocks are designed to be installed and locked in the curtain track to block the movement of any trolleys that should remain stationary.  The design dimensions are specific to the particular kind of curtain track used.  See the image with the track dimensions.

It is not necessary to remove the tracks to install the stop blocks. The blocks are designed so that they can be inserted through the gap in the trolley track then turned 90 degrees and locked in place with a screw.  There's an M3 brass threaded insert in the stop block.  The locking screw can be either a set screw (M3 X 12 mm) or a machine screw (M3 X 16 mm).

Two of the corners of the stop block are radiused, allowing it to be turned 90 degrees clockwise when inserting but keeping it from turning beyond that.  As the jack screw is tightened, the square boss engages the track slot, locking it and preventing the block rotating in either direction

The hole has three diameters.  The smallest is a clearance hole for the screw shank.  The next is the pull-in fit for the brass insert, sized so the insert can be pulled in with a screw; heat setting is not necessary.  The largest part of the hole is just clearance below the insert (actually above, with the block installed in the track).  

Bill of Materials:

3D Printed:

• - Stop Block

Parts Box or Purchased:

• - M3 x 3 x 5mm Female Press in Thread Brass Inserts Embedment Nuts

https://www.amazon.com/gp/product/B07D683Q26/

• - M3 x 12mm Internal Hex Socket Set Grub Screws 304 Stainless Steel Flat Point Set Screw (or M3 X 16 mm machine screw)

https://www.amazon.com/dp/B0CZ6X8T4C?

Printing Notes:

PLA; 0.4 mm nozzle; 16% infill; 0.8 mm shells; no supports; orient with square boss facing up