How to Install a Flush Sash Lift

Press a sheet of paper against the top surface of the sash lift to create an imprint of the recessed opening.

Cut the paper around the imprint with scissors.

Place the paper template you created on the face of the sash lift to compare the openings. If the template opening matches the depression in the sash lift, proceed. If the template opening is too small, trim it until they match. If the template opening is too large, make a new template. If your lift came with a template, use it instead of making one.

Position the paper template on the sash where you want to install the lift, and secure it with painter's tape. You can install one lift, centered along the face of the lower sash, or install a pair of lifts with one on each side.

Trace the outline of the template’s opening onto the sash with a pencil, and remove the template.

Measure the depth of the sash-lift depression with a ruler.

Drill holes into the window sash around the interior of the pencil outline with a power drill and a small drill bit. The size of the bit is not important, but a larger bit is more difficult to control. Drill each hole to a depth slightly less than the depth measurement of the sash lift. Do not drill completely through the sash.

Place the tip of a 1-inch wood chisel against the sash inside the pencil outline. Angle the chisel as parallel to the sash as possible; don’t point it directly at the sash.

Tap the end of the chisel lightly with a hammer, chipping out small bits of wood. Chisel out as much material inside the pencil line as possible, without cutting deeper than the drilled holes.

Stop chiseling periodically to test the fit of the sash lift. Push the lift into the chiseled depression, remove it and chisel away more wood as necessary, until the lipped edge fits flush against the sash.

Switch to smaller chisels as needed to cut more precisely around the perimeter of the opening.

Push the lift back into the chiseled opening.

Insert the accompanying screws through the screw holes in the lift and into the sash with a Phillips or flat-head screwdriver, depending on the style of screws.