How to Cut Wood Window Jambs to Fit a Sill
The bottom of wooden window jambs may need to be cut in order to fit correctly against an existing sill. Sills are slanted at a downward angle towards the exterior to allow for water drainage. The angle of the sill varies based on the manufacturer of the original window, but is usually between 10 and 15 degrees. A sliding T-bevel and protractor allow you to measure and cut the bottom of the jambs to fit tightly against the sill. Does this Spark an idea?
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Instructions
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Position the sliding T-bevel with the sliding portion against the sill where it joins with the outside edge of the rough opening. Unlock the bevel and slide the handle portion so that it is flush with vertical framing on the rough opening. Lock the bevel in place.
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2
Measure the bevel angle from the outside edge of the bevel to the outside edge of the handle portion of the sliding T-bevel with a protractor. This is the angle required for the jambs to fit the sill.
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3
Adjust the miter saw to cut the angle required for the jambs to fit the sill. Cut the angle on each jamb with the miter saw.
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4
Sand the cut edge smooth with 120-grit sandpaper. Always sand with the grain.
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5
Measure the opening from the top of the window to the bottom where the outside edge of the jamb will be placed. This is the length required for the jamb to fit into the opening.
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Place the tip of the tape measure on the long point of the cut side of each jamb and measure the length required for the jamb. Mark the measurement on each board.
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Adjust the miter saw to make a 90-degree cut. Saw each jamb to length at the pencil marks.
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Tips & Warnings
Test the angle on a scrap piece of wood to make sure your measurements are accurate prior to cutting the jamb boards.
Wear eye protection when cutting and sanding wood.
References
- Photo Credit corner miter 4 image by nebari from Fotolia.com
