Finding your LCN closer's model number

Most LCN closers have the series or model stamped directly on the body, near the packing nut at the base of the pinion where the arm attaches. Mechanical products carry a stamped month and year date code in the same area. Spring tube products carry their label on the cylinder itself. Get the model number first, because LCN arm parts aren't universal across the whole catalog the way some buyers assume.

Arm types and what each one does

A regular arm mounts on the pull side of the door and ships standard with roughly 95 percent of LCN closers, which is why the 3077 regular arm is the part number you'll order most often. A parallel arm mounts on the push side instead, with the arm running parallel to the closed door, and it's the configuration used when you don't want the arm visible from the pull side. A hold-open arm adds an adjustable nut that locks the door open at a preset position, useful on doors that need to stay propped during business hours without a separate hold-open device. Cush-n-stop and extra-duty arms add a built-in door stop function to the arm itself for high-abuse applications like cafeteria or gymnasium doors, so the wall or trim doesn't take the impact.

Cylinder spindle shapes vary by series, and this trips people up constantly

Not every LCN closer has the same spindle shape on the cylinder, and ordering an arm that doesn't match the spindle is the single most common mistake on a parts order. The 4040 series uses a six-sided spindle. The 4010, 4020, and 4110 series use a flat-sided oval. The 1260 and 1460 series use an eight-sided star. If you order an arm built for the wrong spindle shape, it simply won't seat, so always confirm the closer model before ordering the matching arm.

Adjusting sweep, latch speed, and backcheck

Most LCN closers allow independent adjustment of sweep speed, latch speed, and backcheck through separate valves on the cylinder body. Backcheck cushions the door's swing near the end of its arc, which prevents the door from slamming into an adjacent wall or piece of furniture on a hard push. Sweep speed governs how fast the door closes through most of its travel, while latch speed controls the final few inches into the frame, slow enough to avoid slamming but fast enough to ensure the latch actually engages.

Looking for a Sentronic electromechanical closer or an automatic operator instead of a standard mechanical closer? See our full LCN door closer parts guide for series-by-series breakdowns, or browse door operators for low-energy automatic options.

Why order LCN door closer parts from Security Parts

We've supplied commercial door hardware parts since 2001, and LCN closers are one of the categories where matching the exact arm and spindle shape genuinely matters. We stock arms, covers, and cylinder assemblies for current and older LCN series, ship most in-stock orders the same day, and offer free shipping on orders of $300 and up. If you're not certain which spindle shape your closer uses, send us the stamped model number and we'll confirm the matching arm before you order.

How do I know which arm fits my LCN closer?

Check the closer's stamped model number first, then match the spindle shape. The 4040 uses six-sided, the 4010/4020/4110 use oval, and the 1260/1460 use eight-sided star spindles.

What's the difference between a regular arm and a parallel arm?

A regular arm mounts pull side. A parallel arm mounts push side and runs parallel to the closed door.

What does backcheck do?

It cushions the door's swing near full open to stop it from slamming into a wall or fixture on a hard push.

Can I add hold-open function to a closer that doesn't have it?

Yes, a hold-open arm can usually be retrofitted onto a regular-armed closer since the hold-open function lives in the arm, not the cylinder body.

Where do I find the date code on my closer?

Near the packing nut at the base of the pinion where the arm attaches, on mechanical models.

Are these genuine LCN parts?

Yes, we stock OEM LCN components alongside compatible aftermarket parts, and we'll tell you which is which before you order.

What if my LCN closer model isn't listed?

Send us the stamped model number and date code and we'll confirm whether we carry parts for it, including older or discontinued series.