COTTONWOOD HARDWARE - 2640 26-4 Block and Tackle Cartridge Channel Balance

Why I reached for a 26-4 channel balance

A dragging, reluctant sash is more than a nuisance—it’s a safety risk and a daily frustration. One of my upstairs double-hung windows had started to slam shut unless I babysat it on the way down. Rather than replace the whole unit, I swapped in a 26-4 channel balance, and that proved to be the fix the window needed. It restored smooth travel, stopped the mid-rail from drifting, and brought the sash back to that satisfying “stays where you leave it” behavior.

What this balance is and where it fits

This is a block-and-tackle cartridge channel balance designed for single- or double-hung windows. It’s the conventional 1/2-inch steel channel style with plastic end guides, a pulley, and a spring inside. The “26-4” (also written “2640”) stamp corresponds to the balance’s nominal length and spring strength. In practical terms:

• Nominal length: 26 class (metal channel length; overall length is about 28 inches including the plastic guides)
• Spring rating: #4, typically used in pairs to support sashes in the 19–26 lb range
• Sold individually: you’ll need two for one sash

If your existing balance is stamped 26 4, 26-4, or 2640, this is the category you’re looking at. Matching the stamp on your old channel is the single easiest way to get into the right range.

Selecting the right replacement

Picking the correct channel balance comes down to three checkpoints:

1) Read the stamp on your old balance

The imprint on the steel channel is your first clue. If it says 26 4 or 2640, you’re in this strength band. The last two digits map to the spring’s “weight range,” not an exact pound figure.

2) Measure the metal channel only

Ignore the plastic ends when measuring length. The size class refers to the metal channel, not the overall length. Length and spring go hand-in-hand, so mixing a different length and a similar strength code is asking for trouble.

3) Confirm the end guides and attachments

Visually compare the top and bottom plastic guides and the bottom attachment style to your old one. The geometry of those ends matters for fit and operation. Most standard 1/2-inch balances with the common top cap and bottom shoe layout will match, but take a close look at the profiles.

A word on sash weight: the 19–26 lb figure is per pair. If you only replace one side (I don’t recommend this), the system will be out of balance. Weigh the sash if you’re unsure—bathroom scales and a careful setup will get you close enough.

Installation: tools, timing, and safety

Tools I used:
- Flathead screwdriver
- Phillips screwdriver
- Needle-nose pliers
- Painter’s tape (to mark stop positions)
- Safety glasses and gloves

Time required: about 20–30 minutes per side, a bit longer the first time.

Basic sequence I followed on a non-tilt double-hung:
1) Support and remove the sash. Don’t trust a tired balance to hold it.
2) Pull the take-out clips (if present) down and set them. This holds the balance shoe so you can unhook it without fighting spring tension.
3) Unscrew the top of the old balance from the jamb, then release the bottom hook/clip from the sash track.
4) Compare the old and new balances side-by-side: metal length, guide shapes, and terminal hardware.
5) Install the new balance: top screw first, then hook the bottom into its anchor in the sash track.
6) Release the take-out clips, reinstall the sash, and test travel before replacing any stops.

Tips that helped:
- Label left and right if you remove both at once; it reduces rework if your window uses mirrored shoes.
- Lubricate the track very lightly with a silicone-safe spray (avoid oils that attract dust).
- Replace both balances together. Mixed ages and spring strengths cause creep and uneven wear.

Safety note: springs store energy. Keep hands clear of the pulley path, and don’t pry on a loaded shoe. If you need to re-tension, reset with the take-out clip in place.

Performance after the swap

With the 26-4 pair installed, the sash behavior improved immediately:
- Lift force: noticeably reduced but not floaty; the sash rises smoothly without the “stepped” feel of a tired spring.
- Holding position: it stays put at quarter, half, and three-quarter openings without creeping up or down.
- Closing: consistent drag with no slam at the last few inches.
- Noise: minimal—just the faint, expected whisper of the cord over the pulley.

I tested by stopping the sash at several heights, then tapping the mid-rail. It didn’t drift. After a week of daily use, the travel remained consistent, and there was no sign of the jumpiness you sometimes get with mismatched or undersized springs.

Build quality and design

• Channel: straight, cleanly stamped steel with good corrosion resistance out of the box.
• Pulleys and spring: tension felt properly calibrated for the “4” strength; no twang or chatter.
• Plastic guides: square, true, and snug in the track; rivets seated tight with no flashing or proud edges.

This is a conventional design done competently. The real test of a channel balance is consistency, and both units I installed were matched—no side-to-side bias or uneven pull.

Where it shines

• Standard replacements: If your old balance is stamped 26 4/2640, this drops right in.
• Mid-weight sashes: The 19–26 lb target range is a sweet spot for many residential double-hung units.
• DIY-friendly upgrades: The inclusion of clear sizing guidance and straightforward hardware makes this accessible if you’re reasonably handy.

I also appreciate that it’s sold individually. While you should buy a pair for a sash, being able to replace a single damaged unit in a set you already have on hand is convenient.

Limitations and things to watch

• Not a universal fit: The 26-4 stamp and length must match; end cap shapes matter. Compare your guides carefully.
• Weight-specific: If your sash is outside the 19–26 lb range, this isn’t the right spring. Go up or down a strength code as appropriate.
• Sold as a single unit: Easy to miss if you assume a pair—order two for one sash.
• Length labeling can confuse newcomers: Remember that the size class refers to the metal channel, not the overall length including plastic guides.

If your window uses a tilt-balance system with a different shoe or pivot geometry, this style is not the right animal. Confirm your window type before ordering.

Value and who should buy it

Replacing channel balances is one of the highest-ROI window repairs you can do. A pair of properly matched balances can rejuvenate a window for a fraction of the cost of a sash or frame replacement. The 26-4 channel balance hits the best parts of that value proposition:
- It’s straightforward to identify by the stamp on your old unit.
- It installs with basic tools and a modest time investment.
- It restores smooth, safe operation and halts the gradual damage that slamming sashes can cause to locks and meeting rails.

Homeowners comfortable with minor carpentry will find this a friendly project. Pros will appreciate the predictable spring range and standard geometry.

Final recommendation

I recommend the 26-4 channel balance for any single- or double-hung window originally equipped with a 26-4/2640 balance and a sash weight in the 19–26 lb range. It installs cleanly, restores smooth travel and position holding, and the build quality is consistent. Pay careful attention to sizing and end-guide matching, buy a pair per sash, and take a few safety precautions during the swap. Do that, and you’ll get a window that operates the way it should—quietly, reliably, and without the daily wrestle.