Sled, miter gauge and fence
Three guides move work past the blade, and each has one job. Mixing them — guiding a crosscut with the fence and a gauge or sled together — traps the cut-off piece against the blade, which is why saw makers forbid it.
| Guide | Rides in or on | References the work by | Used for |
|---|---|---|---|
| Rip fence | The saw's rails | The work's edge against the fence | Rip cuts, along the grain |
| Miter gauge | One miter slot | The work held against the gauge face | Crosscuts and miters |
| Crosscut sled | One or both miter slots | The work carried on the base, against the sled's fence | Crosscuts, especially of wide boards and small parts |
SawStop and DEWALT both direct crosscuts to the miter gauge and rips to the fence, with the fence kept out of contact with the work during a crosscut; a sled replaces the gauge, not the fence.
The limits sled makers set
POWERTEC's manual for its 71403 sled is a useful example of how specific those limits are. Its sled is for cabinet and full-size contractor saws with a standard 3/8 in deep × 3/4 in wide miter slot — not for portable saws — and needs at least 4-1/4 in between the blade and the slot so the fence clears the blade.
- No rip fence while the sled is in use.
- No dado blades with this sled, and no compound cuts.
- Outfeed support must not obstruct the sled's miter bar.
- Fence and hold-down positioned so they cannot touch the blade, and every knob and the hold-down tightened before cutting.
- Blade height as low as possible for the cut, as defined by the saw's own manual.
- Pieces too short to be secured with the hold-down are not cut on the sled.
- A cracked part means the sled is taken out of use immediately.
Blade height is one point where sources differ: POWERTEC says as low as possible, defined by the saw's manual, while SawStop's and DEWALT's saw manuals set the blade about 1/8 in above the work. Follow your saw's manual and your sled's together; where they conflict, ask the makers rather than splitting the difference.
Equipment notePaid link
Table saw crosscut sled
POWERTEC 71403
POWERTEC's 71403, the sled this section quotes: made for cabinet and full-size contractor saws with 3/8 × 3/4 in slots, and at least 4-1/4 in from blade to slot.
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Runners
A sled is only as accurate as its runners' fit in the slots. INCRA gives the common slot as 3/4 in wide and 3/8 in deep, with or without a 15/16 in T-slot below, and makes its miter bar adjustable for slots from 0.740 to 0.765 in wide — a reminder that real slots vary. POWERTEC's aluminium bar is 3/4 × 3/8 in with nylon adjustment screws, and the manual's test is simple: the bar must slide freely forward and back without side-to-side play. Never force a sled that does not slide freely. Freud's sled plan says the same of wooden runners: suitable for your slots, sliding freely, with no sideways movement.
Squaring the fence
POWERTEC squares its sled's fence with a combination square against the blade, touching only the plate — not the teeth, which are wider. That sets the fence close. To measure what is left, the five-cut check multiplies the error until it can be read.
Running the five-cut check
Take a square-ish board
Any flat board with four straight edges, wide enough to sit securely on the sled. You will number the edges in the order you cut them.
Cut 1
Hold any edge against the fence and trim the edge next to it. Mark the trimmed edge 1.
Cuts 2 to 4
Turn the board a quarter so edge 1 is against the fence and trim the next edge, marking it 2. Keep turning the same way: edge 2 against the fence to cut edge 3, edge 3 to cut edge 4.
Cut 5
Turn once more, so edge 4 is against the fence, and take a narrow strip off edge 1.
Measure the strip
Measure its width at both ends, the same distance in from each end; call them A and B, and note the distance L between the two points.
Work out the error
Any fence error is added once at each turn, so A − B is about four times the error of a single cut over the length L.
Five-cut error
error per cut ≈ (A − B) ÷ 4
angle ≈ (A − B) ÷ (4 × L) radians
- A, B
- strip width at its two ends (in)
- L
- distance between the two measurements (in)
Worked example with made-up readings: A = 0.020 in, B = 0.004 in over L = 20 in gives (0.016) ÷ 4 = 0.004 in per 20 in of cut, an angle of 0.0002 rad, about 0.01°. Move the fence by that amount at the end of its length, and recheck.
Building one
Freud's published plan for a dado sled shows the parts any shop-made sled needs: a 1/2 in plywood base, hardwood runners sized to the saw's slots, a main fence, support blocks and a polycarbonate safety guard. Freud presents it as one of many ways to build a sled. Whatever the design, the runners go on first, fitted to slide freely without play; the base is set parallel to and centred over them; and the fence is squared to the kerf the saw cuts in the base. A complete shop-made build is in the crosscut sled plans; if a manufactured sled suits the saw better, choosing a sled compares the options.
Before the first cut on a sled
- The sled is made for your saw type and slot size
- The runners slide freely without side play
- The rip fence is off the saw or well clear of the sled
- The fence and any hold-down cannot reach the blade
- The work is long enough to clamp, and is held against the fence
- The blade height follows your saw's and sled's manuals
- Outfeed support is clear of the runners
Sources
The limits quoted are POWERTEC's for its own sled and saws; other sleds give their own. The five-cut check is shown as geometry for checking any fence, not as a maker's procedure or tolerance.
- 1.
Owner's Manual, Model No. 71403 Table Saw Crosscut Sled. POWERTEC.
Used for: POWERTEC's limits for its 71403 sled: cabinet and full-size contractor saws with a standard 3/8 in deep × 3/4 in wide slot, not portable saws; at least 4-1/4 in from blade to slot; out-feed support clear of the miter bar; no rip fence and no dado blades with the sled; no compound cuts; fence and hold-down clear of the blade; the blade as low as the saw's manual allows; a bar that slides freely without side play; no pieces too short for the hold-down; stopping use if a part cracks; squaring the fence with a combination square on the blade plate.
- 2.
INCRA Miter 1000SE. INCRA.
Used for: Slot dimensions of 3/4 in wide and 3/8 in deep, with or without a 15/16 in T-slot, and a bar adjustable for slots 0.740 to 0.765 in wide.
- 3.
Creating a Dado Sled — safety instructions. Freud Tools.
Used for: Freud's sled plan: runners sized to the saw's slots that slide freely without sideways movement; a 1/2 in plywood base; the base set parallel to and centred over the runners.
- 4.
Owner's Manual, 10" Professional Cabinet Saw, Model PCS31230. SawStop.
Used for: The miter gauge for crosscuts and the rip fence for rips; the rip fence kept out of contact with the work when crosscutting; blade height about 1/8 in above the work.
- 5.
DWE7491 10" (254 mm) Job Site Table Saw, Instruction Manual. DEWALT.
Used for: Blade height about 1/8 in above the work; never using the fence as a length stop when crosscutting.
About this guide
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