PRIME-LINE F 2590 Sash Lock for Vertical and Horizontal Sliding Windows – Replace Broken Sash Locks for Additional Home Security, 2-1/4” Mounting Hole Centers, White Diecast

I keep a small bin of spare window hardware for rental turnovers and home fixes, but one item I tend to buy fresh is a sash lock. The Prime-Line sash lock (F 2590) has become my go-to for aluminum-framed sliders and single/double-hung aluminum windows because it does the basics well: it fits the common 2-1/4-inch hole spacing, it engages directly into the fixed rail without a separate keeper, and it’s tough enough to outlast the plastic and thin aluminum latches I still find on older windows.

What this lock is—and isn’t

This is a single cam-action latch with a 3/8-inch projection. Instead of a two-piece system with a separate keeper, the cam swings over and bites into the fixed rail of the opposing sash. That makes it ideal for quick replacements: fewer parts to align, fewer opportunities for misfit. It’s diecast zinc with a white painted finish, and the body profile is low enough to sit cleanly on most aluminum rails without snagging blinds or drapes.

It’s designed for aluminum, not vinyl or wood, and that matters. The geometry of the cam and the reliance on the opposing aluminum rail for engagement means you’re counting on a specific shape and stiffness. On vinyl, you’ll often need a different style lock with a dedicated keeper. Consider this a direct-replacement solution for aluminum frames first, with “some horizontal sliders” as a realistic secondary fit.

Fit and compatibility

The headline dimensions were accurate in my installs:

• 2-1/4-inch center-to-center mounting holes
• 3/8-inch cam projection

On a mid-90s single-hung aluminum window, it dropped into the old footprint and covered the original outline completely. The cam engaged the pocket firmly and pulled the sashes together with a reassuring snap—tight enough to stop the small rattle I could never quite eliminate with the worn original.

On a horizontal slider from the same era, it also fit, but I needed to be more deliberate about alignment. Because there’s no separate keeper, the opposing rail’s groove depth and angle determine how cleanly the cam seats. If your rail is slightly deformed or the sashes don’t meet square, the cam can feel like it’s binding as you rotate it. In one case, a careful re-seating of the sashes and a thorough track clean solved it; in another older frame with a shallow pocket, I eased the leading edge of the cam very lightly with a file to establish a smoother radius. After that, it locked and unlocked smoothly.

If you’re working on a horizontal slider, my advice is to test the action with the screws loosely installed. Close the window firmly, pull the sash fully into the frame, then rotate the cam. If it bites early or feels tight, you may need to tweak alignment or verify that the opposing rail has a suitable groove.

Installation

This is a 5–10-minute job if your hole spacing matches.

• Measure center-to-center distance on your existing lock. If it’s 2-1/4 inches, you’re in business.
• Dry-fit the lock and loosely set the screws so you can shift it a millimeter or two during testing.
• Fully seat the sashes before operating the cam; don’t “pull” the sashes together with the latch—let the latch do the final snug, not the heavy lifting.

A note on the included screws: they’re functional sheet-metal screws, but their length can be marginal for some frames. On one thin aluminum rail, the tips threatened to poke into the glazing channel. I reused the original shorter screws and avoided the risk. If you’re unsure, mark your bit with tape as a depth stop and pre-drill carefully, or have a pair of shorter pan-head screws on hand.

Also worth noting: there’s no left/right version here. You can flip the body to suit orientation.

Build quality and feel

The body is solid for a diecast part, and the cam doesn’t exhibit the flex I see on some lightweight replacements. The white finish is clean and even, not chalky, and it has held up after several months without chipping. If you have bronze or dark frames, the white will stand out; you can paint it with a metal-rated enamel after a light scuff, but out of the package it’s plainly meant to blend with white or light aluminum.

The action is positive. With the sash properly seated, the cam rotates with predictable resistance and delivers a firm clamp between sashes. That compression helps reduce minor drafts and rattles. A drop of silicone on the cam’s contact point makes it even smoother and prevents squeaks.

Security and performance

No cam latch on an aluminum sash turns a window into a safe. This style improves everyday security by:

• Pulling the sashes together firmly, which deters casual prying
• Maintaining alignment so the window can’t be worked open easily from outside

For rentals or older homes where the original locks are failing, a fresh, tight latch like this is a meaningful step up. For ground-level windows, I still pair it with a secondary device—an auxiliary pin or a simple dowel in the track—especially on horizontal sliders.

Real-world quirks

• Tolerance stack matters. If the frame is out of square, you’ll feel it in the cam. Clean the tracks and make sure the sash is fully closed before operating the lock. Don’t use the latch as a clamp to drag a reluctant sash home.
• Screw length is worth a double-check. If you see glass or a glazing bead under your screw path, use shorter screws.
• On one older slider with a very shallow opposing pocket, the cam’s leading edge felt too abrupt. A minute of careful filing rounded the edge and solved the bind. Not typical, but something to keep in mind for oddball frames.

Who will appreciate it

• Homeowners and landlords with aluminum single- or double-hung windows whose original latches are bent, loose, or broken
• DIYers looking for a quick, keeper-free replacement that relies on common 2-1/4-inch spacing
• Anyone chasing down rattles and minor air leaks on otherwise serviceable aluminum windows

If your windows are vinyl or you need a lock with a dedicated keeper, this isn’t the right style. Likewise, if your horizontal slider’s opposing rail doesn’t present a decent groove, you’ll want to stick to a matched two-piece system.

Tips for a clean result

• Measure twice: center-to-center hole distance and the depth of the opposing rail’s catch pocket.
• Test with the screws barely snug, then tighten once you like the cam’s feel.
• Clean tracks and meeting rails; the cleaner the seat, the easier the cam engages.
• Consider a dab of threadlocker if your previous screws tended to loosen over time.

Bottom line

The Prime-Line sash lock hits the sweet spot for aluminum window repairs: simple geometry, accurate sizing, and a sturdy cam that does what it’s supposed to do. It doesn’t pretend to be a universal solution, and that’s fine—within its lane, it’s reliable and easy to live with.

Recommendation: I recommend this lock for aluminum-framed windows that match the 2-1/4-inch hole spacing and can accept a 3/8-inch cam projection into the fixed rail. It installs quickly, firms up loose sashes, and restores basic security without the hassle of aligning a separate keeper. Check your screw length, confirm the opposing rail has a suitable groove, and you’ll likely be pleased with the fit and function. If your frames are vinyl, out of square, or require a two-piece latch, choose a system designed for those conditions instead.