Yes, you can trim a door with an oscillating tool. An oscillating tool, also known as a multi-tool, is a versatile power tool that can be used for cutting, sanding, grinding, scraping and more. With the right blades, an oscillating tool is an effective tool for trimming and fitting doors.
Some key advantages of using an oscillating tool to trim doors include:
- Precision – Oscillating tools allow for detailed and accurate cuts, which is important when trimming doors to size.
- Control – The narrow blade and quick oscillating motion gives you more control over the cut than using a circular saw.
- Flexibility – You can use different blades to undercut door jambs or make flush cuts.
- Safety – Less risk of damaging the material or yourself compared to other saws.
- Convenience – Compact size and cordless options allow you to bring the tool wherever needed.
With some practice and the right techniques, most common door trimming and fitting tasks can be completed with an oscillating tool.
Page Contents
Cutting Door Height
One of the most common door trimming tasks is cutting a door to size height-wise to fit the doorway opening. Here are some tips for cutting door height with an oscillating tool:
- Use a fine-toothed universal wood cutting blade suitable for the door material (solid wood, hollow core, fiberglass, steel, etc.). Bi-metal blades offer longer edge life.
- Mark the cut line with a pencil, allowing 1/8″ clearance under the door. For accuracy, measure up from the bottom rather than down from the top.
- Set the door horizontally on a stable work surface, with the edge to be cut overhanging the edge. Clamp a straightedge guide flush to the door edge to follow.
- Set the oscillating tool to maximum speed. Keep an even pressure and steady feed rate moving the tool from hinge side to latch side.
- Take multiple passes, incrementally deepening the cut until through the door. For thick doors, you may need an extended length blade.
- Go back and forth over the cut to clean up any splinters or rough edges.
When working on an interior door, be sure to cut the top edge so the door swings into the room you are trimming for.
Trimming Door Width
Oscillating tools also work well for trimming doors to narrower widths to fit openings. Here are some tips:
- Use a blade designed for cutting curves and scrollwork to follow the door edge profile. Choose fine tooth pattern.
- Carefully measure and mark the new width, double checking for accuracy.
- Cut off the excess starting at the bottom corner, moving up one side, then repeating on the other side.
- Make multiple light passes rather than trying to cut through in one pass.
- Position the tool so the blade cuts on the waste side of the line to leave a clean door edge.
- Use an 80-100 grit sanding blade to blend the cut edge and round over the profile.
Be very careful when trimming width on doors with glass panels. Remove panels first or use a protecting backing board.
Undercutting Door Jambs
For doors to swing freely over flooring, the bottom of the door jamb is often undercut to provide clearance. Here is how to undercut a door jamb with an oscillating tool:
- Select a carbide-grit grout removal blade, which is narrower than wood cutting blades.
- Mark the height needed for clearance. Typical undercut depth is 3/4″.
- Tilt the tool sideways and use an in-and-out motion working along the jamb bottom.
- Make multiple light passes until reaching the correct depth. Avoid digging in too aggressively.
- Vacuum dust and use a chisel or utility knife to clean corners.
The narrow grout blade allows smoothly cutting back to the doorstop while leaving jamb edges clean. Go slowly to avoid damaging the flooring.
Cutting Door Casing
For door installations requiring narrower casing or trim, oscillating tools provide a nice solution for precision trimming:
- Mark the new width on the casing and set up a straightedge guide.
- Use a smooth cutting wood blade and make multiple light passes trimming to size.
- Trim mitered corner cuts starting from the outside corner moving inward.
- Change to a sanding blade and blend trim edges for a smooth finish.
The thin profile of oscillating tool blades makes it easy to trim door casing in place without marring adjacent walls or flooring.
Fitting Doors in Frames
For final door fitting, oscillating tools help shave and plane doors for the proper fit:
- Use a 80-100 grit sanding blade to remove thin amounts from door side and top/bottom edges.
- Keep the tool moving constantly and use light pressure to slowly shave the door.
- Change to a carbide rasp for smoothing and evening out areas.
- Always work door edges evenly to prevent binding. Frequently test fit.
The ability to safely remove small amounts of material makes oscillating tools ideal for final door fitting.
Cutting Recesses for Hidden Hinges
Oscillating tools equipped with special hinge cutting blades can rout out recesses for installing hidden (European style) door hinges:
- Measure hinge locations and mark centerlines for each recess.
- Use layout lines to position the plunger guide and pivot base.
- Make multiple passes with hinge blade, gradually deepening the recess.
- Test fit hinge and continue to route until flush and level.
- Use a chisel to square corners and sanding blade to clean up.
This provides a cleaner look versus surface screwing standard butt hinges.
Door and Frame Prep
In addition to trimming, oscillating tools come in handy for other door prep work:
- Mortising – Quickly plunge cut mortises for locksets and door closers with a mortising blade accessory.
- Hinge routing – Recess hinge leafs into door edges with the proper blade.
- Door/Jamb scribing – Trim jambs and doors for an exact mating fit.
- Hardware holes – Quickly cut holes for knobs, cylinders, bolts, patching/repair.
Tips for Trimming Success
Follow these tips and techniques for best results trimming doors with an oscillating tool:
- Use sharp, quality blades designed for the material.
- Cut shallow depths per pass, working up to the layout line.
- Keep straightedge guides flush and tool stable.
- Allow clearance for finish trimming and fitting – don’t cut precisely to final size.
- Always cut doors oversized at bottoms.
- Work slowly with light pressure – don’t force or overload the tool.
- Clamp workpiece whenever possible for maximum control.
- Keep variables consistent – same tool speed, blade, pressure, feed rate.
Conclusion
An oscillating tool is an excellent choice for most common door trimming and fitting operations. It allows making detailed cuts safely and accurately with less mess than other saws. Follow proper techniques for clean, precision trimming results. With practice, an oscillating multi-tool can be used to notch, trim and fine-tune doors for a perfect custom fit.