When working on finish carpentry at a job site, a portable tablesaw is an indispensable companion for cutting window casings to sizing cabinet components. Yet every builder who relies on a compact saw eventually faces a frustrating limitation: the narrow fence-to-blade gap makes thin rip cuts off wide stock nearly impossible. Whether you need to shave a hair off a sheet of plywood or trim a fraction of an inch from a hardwood panel, the standard fence design has a dead zone that prevents close cuts. By building an auxiliary wooden fence for your tablesaw, you can make precise cuts as thin as a sixty-fourth of an inch, opening up new possibilities for finish carpentry at the highest level of accuracy.
Understanding the Close Shave Problem on Portable Tablesaws
Most job site tablesaws sacrifice table size for portability. A typical contractor saw has a table depth of 22 to 24 inches and a width of 18 to 20 inches. The fence rides on rails that extend beyond the table surface, but the effective cutting width is limited by how far the fence face can travel past the blade insert. When the fence is positioned flush with the blade, the fence face sits directly over the blade slot, leaving no room for the workpiece to pass between them. This creates a dead zone of about an inch or more where the fence cannot guide material past the blade.
The solution is to attach a sacrificial wooden auxiliary fence to the metal fence. This auxiliary fence extends past the blade on the operator side, shifting the fence face away from the blade slot. By raising the spinning blade up through the wooden fence, you create a precise channel that allows the blade to pass through while the fence guides the workpiece. This technique, published in Fine Homebuilding magazine, has been used by finish carpenters for decades.
When Close Shave Cuts Become Necessary
Several job site scenarios require thin rip cuts:
- Cabinet scribing. Fitting a cabinet against an out-of-plumb wall requires shaving a sliver off the back edge of a panel. Without a close shave cut, you must plane by hand or accept a gap.
- Plywood panel trimming. Removing a factory edge or adjusting width by a sixteenth of an inch is common during cabinet assembly.
- Hardwood flooring rip cuts. Taking a sliver off a board to fit against an irregular wall is faster with the tablesaw than with a circular saw.
- Molding scribing. Adjusting crown or base molding width while preserving the face profile on the visible side.
- Custom shim stock. Ripping thin strips from scrap lumber for door hanging, window setting, and leveling work.
Building the Modified Auxiliary Fence
The modified fence is straightforward to build with basic shop tools. The original design uses a simple wooden block screwed to the saw fence. The version described here incorporates refinements for durability and accuracy.
Materials Required
- One piece of knot-free hardwood (maple or birch) 3/4 in. thick, 3 to 4 in. wide, and 24 in. long
- Four flathead wood screws, No. 8 by 1-1/4 in.
- Drill with countersink bit
- An 80-tooth carbide-tipped tablesaw blade
- Pencil and straightedge for layout
Step-by-Step Assembly Instructions
- Prepare the wood blank. Cut the hardwood to length. Ensure it is straight and free of warps. Sand the face that contacts the workpiece to a smooth finish. Any irregularities transfer directly to cut quality.
- Position the blank. Place it against the blade side of the metal fence with the blade lowered below the table surface. Clamp it temporarily.
- Align flush with the blade edge. Position the blank so its outer edge is flush with the outside edge of the blade. Use a combination square to verify. This is the most critical alignment step.
- Drill and countersink. Mark screw locations at least 2 in. from the blade path. Drill pilot holes and countersink them so screw heads sit below the surface.
- Attach securely. Drive screws through the blank into the metal fence. Recheck alignment after tightening to ensure the blank did not shift.
- Cut the blade channel. With the blade lowered, turn on the saw. Slowly raise the blade to full height. The spinning blade cuts a half-moon void into the blank, forming the clearance channel.
- Inspect and test. Verify the channel is clean. Run a test cut on scrap to confirm accurate guidance.
Safety Considerations
Keep your hands clear of the blade path when raising the blade through the fence. Use the saw’s blade-raising mechanism, not your hand near the blade. Wear eye protection. After cutting the channel, verify a small gap exists between the fence material and the blade teeth at full rotation. For more on safety, review essential tablesaw safety upgrades that protect against kickback.
Using the Modified Fence for Precision Ripping
Once installed, the kerf cut into the auxiliary fence serves as a visual guide for ultra-thin rip cuts. The fence provides continuous workpiece support right up to the blade entry point, maintaining guidance throughout the cut where a standard fence would lose contact.
Setting Up for a Thin Rip Cut
- Place the workpiece flat on the table with the edge to be cut facing the fence
- Slide the fence toward the blade until it contacts the workpiece edge
- Position the fence so the material to remove extends past the kerf line visible on the auxiliary fence
- Lock the fence and use a push stick to feed the workpiece through
Blade Selection for Maximum Precision
The blade you choose has a direct impact on cut quality. A high-tooth-count blade produces a smoother cut with less tear-out, which is especially important when removing minimal material.
| Blade Type | Tooth Count | Cut Quality | Best Use Case |
|---|---|---|---|
| General Purpose | 24-40 teeth | Fair, tear-out on thin cuts | Rough framing, plywood crosscuts |
| Combination | 50-60 teeth | Good, moderate tear-out | General ripping and crosscutting |
| Finish / Thin Kerf | 80-100 teeth | Excellent, minimal tear-out | Final dimensioning, close shave rips |
| High-ATB | 80 teeth | Superior for veneered plywood | Cabinet-grade panel trimming |
For best results, use an 80-tooth carbide blade that is sharp and free of pitch buildup. A dull blade produces burning and defeats the purpose of precision cuts. For maintenance, see cleaning saw blades to remove pitch and resin.
Infeed and Outfeed Support
When ripping a narrow strip off a full sheet of plywood, support the workpiece on both sides with roller stands matching the tablesaw table height. A sagging panel pinches the blade or lifts the workpiece off the fence, compromising accuracy. See extending the tablesaw worksurface with infeed and outfeed supports for dedicated support systems.
Feed Rate and Technique
Feed the workpiece at a steady, moderate pace. Do not force the material. A feed rate that is too fast causes burning and may deflect the thin offcut. A feed rate that is too slow also causes burning as the blade dwells. Apply gentle, even pressure against both the fence and the table. Use a push stick for the last 6 inches of the cut.
Troubleshooting and Advanced Applications
Common Problems and Solutions
| Problem | Cause | Solution |
|---|---|---|
| Burning on cut edge | Dull blade or slow feed | Sharpen blade; increase feed rate |
| Rough tear-out on top | Wrong tooth geometry | Use 80-tooth high-ATB blade for plywood |
| Offcut binds between blade and fence | Fence not parallel to blade | Recheck fence alignment |
| Inconsistent cut width | Workpiece not held firmly | Use feather board or push block |
| Blade contacts fence | Channel too narrow or fence shifted | Re-cut channel; tighten screws |
Maintaining the Auxiliary Fence
The wooden fence is a consumable component. Over time, the blade channel widens from vibration or use with different blades. Replace it when the workpiece can drift into the gap. A fresh fence takes under 20 minutes to build. Store it in a dry location to prevent warping.
Expanding the Technique
- Zero-clearance insert. Combine with a zero-clearance throat plate to reduce tear-out on the bottom face of the material.
- Dado cuts. Build a thicker auxiliary fence with a dado-width channel for stopped or through dado grooves.
- Sacrificial feather boards. Attach a feather board directly to the auxiliary fence for improved safety on thin rips.
- Miter gauge extension. Use the same concept as a sacrificial miter gauge extension for close shave crosscuts.
Integrating into a Broader Tool Setup
The auxiliary fence is one of several accessories that transform a basic portable tablesaw into a precision finish carpentry tool. A well-equipped saw should include a rip fence with micro-adjustment, a crosscut sled, and push sticks. For a comprehensive overview, see essential tablesaw tools and accessories every carpenter should have.
By adding this simple auxiliary fence to your portable tablesaw, you eliminate one of the most frustrating limitations of job site saws. The ability to take precise thin rip cuts reduces material waste, speeds up fitting, and delivers higher quality results in finish carpentry and cabinet work. The investment of 20 minutes and a scrap piece of hardwood pays for itself on the first close shave cut.