A basic build of a crucial table saw accessory
A miter gauge is a great tool for crosscutting on the table saw, especially if outfitted with an auxiliary fence. But wide pieces force the miter gauge off the front of the saw table, creating an unsafe situation. And long pieces tend to drag on the table, making cuts inaccurate.
For these reasons and more, most serious woodworkers make a custom crosscut sled for their saw. A sled does everything the miter gauge does, but better. With its broad base, long fence, and double runners, a sled carries workpieces of all sizes smoothly and accurately past the blade with no wobbles, as opposed to dragging them. This makes the sled the more accurate option for workpieces of all sizes, but especially larger ones. The fence also carries the offcut safely past the blade, and provides a place to clamp stop blocks. And the zero-clearance blade slot in the base and fence eliminates tearout on both the bottom and trailing edge of the workpiece.
Making a crosscut sled is not complicated. However, it does entail a couple of exacting procedures, including setting the runners and adjusting the fence, both of which are critical to successful operation of the sled. Not to worry: I’ve got great ways to tame each of these challenges. Follow along here and I’ll show you one of the easiest approaches for outfitting your particular saw with this crucial accessory. I think you’ll be amazed at how much control it provides and the smooth, accurate cuts it delivers.
Five components assembled for accuracy
This simple sled consists of a plywood base, two hardwood runners, and two fences made of MDF. For accurate operation, the sled’s base must be flat and the runners perfectly fit to your saw’s miter gauge slots. The front fence is made of two layers of MDF glued together to ensure that it’s dead-flat and stable when set perfectly square to your saw blade. The fences are shaped to reduce weight and provide easier handling of workpieces. Base dimensions and runner placement are provisional; suit them to your particular saw.
Order of Work
- Make base and runners
- Attach runners
- Make fences
- Attach fences
- Test accuracy
Make the base and runners
I used construction-grade plywood I had on hand for the base, but hardwood plywood is flatter, smoother, and not as heavy as MDF. I made this sled for use on a Bosch jobsite saw, sizing the base at 24 × 36", which is about as large as the saw will safely handle. A full-size table saw can take a larger sled.
Make the runners from straight-grained hardwood. To size the runners for a perfect fit in your table slots, start by planing a board so its edge drops smoothly into the slots. If you lack a planer, you can saw a runner blank as shown. Then rip away the runners to be just a bit shallower than the slot depth. If necessary, you can scrape or sand the runners for a better fit in the slots.
Table saw option for perfect runners. If you don’t have a thickness planer, you can create accurate runner stock on your table saw. Starting with a straight, pre-surfaced hardwood board (available at lumber retailers) 1" or thicker, run it on edge against your rip fence as shown, to trim a section to thickness (left). Start fat, then readjust the fence to creep up on a perfect fit (right). Then lay the board flat to rip away the runner strips you need, making them slightly thinner than the slots are deep.
Attach the runners
To attach the runners, you’ll place them in their slots, tack the base to them, then add screws to the underside. But begin by drilling and countersinking five clearance holes in each runner to accept #6 × 1" flathead screws. Locate the runners and base as shown, then mark the runner locations across the top of the base. Next, drive four 1" brads through the base into each runner to hold it in place for subsequent screwing. Screw the ends of the runners as shown, then upend the assembly to install the rest of the screws. Afterward, wax the runners.
Runner location. Align one end of each runner with the front edge of the saw table. Shim the runners from underneath with coins if necessary to bring them flush to the saw table surface.
Place the base. Align one long edge of the base with the edge of the saw table, with the left side of the base about 15" from the blade. Mark the runner locations and then clamp the setup in place.
Make and attach the fences
In preparation for attaching the fences, drill countersunk clearance holes for #6 screws. One exception: at the left-hand front of the base, drill an oversized clearance hole with a shallow counterbore as shown. As you’ll see, this will allow for adjusting the front fence dead-square to the blade. Next, fully screw the base to the rear fence after drilling pilot holes to prevent splitting the MDF. Then attach the right-hand end of the front fence with a single flathead screw, and the left-hand end with a large panhead screw.
Fence adjustment hole. The left-hand end of the front fence gets attached with a panhead screw that sits in a counterbore. Drill an oversized clearance hole for it to allow initial pivoting of the fence to square it to the saw blade.
Adjust the front fence
Initial blade slot. After attaching the front fence with a flathead “pivot screw” at one end and a panhead screw through an oversized hole at the other end, cut through the rear fence and base, stopping at the front fence.
Initial fence adjustment. Place a very accurate square against the fence and blade to check for perpendicularity, making sure the square rests against the blade plate, not the teeth. If necessary, loosen the panhead screw, and pivot the fence to bring it square to the blade. Then lock down the screw.
Crosscut test. Mark one face of a wide board that has been ripped with straight, parallel edges. Then, with the fence still attached with just one screw at each end, make a test cut (left). Flip one of the halves over edge-for-edge, pull both pieces against the fence, and abut their cut edges (right). If there’s no gap, you’re square. Any gap represents twice the angle error, so go easy when readjusting the fence to try again. When the cuts are square, add the rest of the screws to the front fence, locking it permanently in place.
Using the sled
There’s a reason this sled is longer on its right side. It’s because most saw tables are longer to the right of the blade to accommodate wide rip fence settings. So, just as with ripping, you’ll make most of your crosscuts with the workpiece primarily to the right of the blade, supported by the longer section of the sled’s fence. In addition to general crosscutting, the fence also provides a great place to clamp stop blocks for repeat cuts. If your workpiece reaches past the end of the sled, you can employ an extending hook-style stop as shown below and on p. 47.
Because a sled carries both parts of a separated workpiece past the blade, it tends to be safer than using a miter gauge. That said, a crosscut sled still demands caution, with particular attention paid to the area where the blade exits the front fence. Some woodworkers attach a box or large block of wood at that spot, or paint a big red stripe there, to be sure their fingers never stray into the danger zone. Feel free to add this extra measure of safety.
Stop block for fast accuracy. A stop block clamped to the fence makes for efficient, dead-accurate, repeatable crosscuts.
A long hang-out. For repeatable sawing of workpieces longer than the fence, attach an L-shaped, hooked extension that rides the sled fence.
More from Asa
This second book in the “Build Stuff with Wood” series adds essential machine and hand tools, taking woodworkers to the intermediate level. “Build More Stuff with Wood” includes essential joinery techniques and fresh design ideas. Learn new skills while making 12 new projects for the home and shop.
