Security Door Installation Part 9: Installing Trailing Posts

Trailing Post Fittings

As you can tell from the title, this post is part of a series in which we’re exploring the details of security door installation. The idea is to go beyond the basic instruction manual PDF and provide some extra tips that will help you ensure your Dynamic Closures security grille operates as smoothly as possible.

If you haven’t been following along, you may want to start from the beginning.

What Is a Trailing Post?

A trailing post secures the end of the security grille curtain within a wall pocket.

It has a bit of room to move within the storage pocket, but never leaves it, and so does not need a lock. It prevents intruders from entering the secured area by containing the end of the curtain, and also reinforces the smooth appearance of the grille.

Trailing Post Diagram
In the diagram above, you can see a trailing post simplified top view on the left, and side view on the right.

A Trailing post is always the absolutely last one to be installed, so it can act as a tension adjustment.

Prepare to Install

Get started by fully extending the curtain and locking all the other posts in place.

You should get a feel for the right amount of tension in the curtain. You don’t want it to look loose and sloppy, but don’t make it too tight either, because your users will find it hard to lock, and may inadvertently damage the door while trying.

Be careful at this point, because it’s one of the most important steps in the overall process: if you get this wrong, you’ll be drilling your holes in the wrong spot.

Marking and Drilling the Floor Hole for the V-Stop

The V-stop defines the area of play for the Trailing post within the pocket. It has raised edges that taper towards the front, to catch the post wherever it is in the pocket and ensure it always comes to the correct spot when it is pulled forward.

Now that your door is in final position, you’re ready to mark the holes for the V-stop.

1. Put the V-stop within the pocket, flush with the front connector face of the trailing post, then mark the front mounting hole on the floor. We find china markers or soft pencils work best.
V-stop Positioning Marking
2. Remove the V-stop, and pull the door back out of the pocket area entirely.

3. Next, you’ll need to bend the arms of the V-stop wider or narrower so they perfectly fit both walls of the pocket. This is to ensure that the post can’t escape the stop:
Bend V-stop Arms

4. Replace the V-stop in the pocket to ensure a perfect fit. Then, line up the front edge hole with your mark, and then mark the other 4 holes on the arms.

Nail-in Anchor5. Now you’re ready to drill the holes to secure your V-stop to the floor. Use your drill to make each 1/4” hole, 1 1/4” deep where you made your marks in the pocket. Tap the sockets into the holes. You can review how to drill holes for the floor sockets correctly here.

6. Replace the V-stop and fasten it to the floor using the nail-in anchors provided. Start with the hole in the front edge, and proceed to the rest.

Mounting the Post in the Pocket

Now you have your V-stop stop in place, but you still need to put the post back and position both floor and ceiling stops. These are two flat bars with vertical adjustments.

To get ready, detach the Trailing post from the curtain (reverse the directions you followed here), and raise the bottom stop enough to pass over the V-stop. It should now be behind the V-stop.

Secure the Post to the Floor

1. Loosen the retaining screws and lower the bottom stop until it is just off the floor. Check that the stop clears the floor though the entire pocket are. Adjust if necessary – ensure it won’t scrape the floor at any point in the pocket, but also that it can’t float over the V-Stop.
Floor stop and retaining screws

2. Move trailing post until the bottom stop is up against the front of the V-stop.
Floor stop meets V-stop

Secure to the Ceiling Track

Check that the post is hanging plumb, and that the floor stop is resting securely against the V-stop.

The U-stop is supplied – it’s a u-shaped piece of metal – along with appropriate screws:
Ceiling Stop Bracket

As with the V-stop you mounted on the floor, all it does is create a physical barrier at the appropriate point in the ceiling track.

1. Just in front of the ceiling stop in the post, drill up into the U-stop through the header track with the #10 x 2” screws:
Installing U-stop

2. Loosen the hex bolts to adjust the height of the top stop:
Loosening Hex bolts

3. Raise the top stop so that it catches to U-stop on the ceiling. Check the height so that it doesn’t scrape the ceiling, but that it can’t help but catch on the U-stop. As a rule of thumb, leave as little clearance as possible between the top stop and the ceiling:
Ceiling stop catching U-stop

4. You final step is to re-attach trailing post to your security grille curtain (again, reverse the directions you followed here).


Unless you have a Fixed post, you will now have a completely attached security door that will move smoothly along the track, and that looks nice and taut when closed. In the next few posts, we’ll cover how to make fine adjustments to things like the height of locks in posts. We begin with fixed posts and pull straps in Part 10 here.

If you run into questions or problems at any point in the installation process, our expert Customer Service Team is on hand to help. You can reach them at 1-800-663-4599 from Monday to Friday 8 AM-5 PM Eastern time.

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