Now that the sled base and fences are complete. the next step is to attach the fences to the base and add the runners. This installment will detail the step by step process to finish up the sled. The final installment will cover fine tuning to improve the sled’s performance.
Temporarily attach the rear fence
Drop the zero clearance plate into the slot in the base and align the rear fence to the plate. Clamp the rear fence to the lower sled base, aligning the rear edge of the fence to the rear edge of the base. Drill and countersink one hole from underneath the base at each end of the fence and attach it to the base.
IMPORTANT: DO NOT drill more than two holes or use any glue. You will be fine tuning the fence later. This is only a temporary attachment.
Attach the front fence.
Attach the front fence by setting the removable plate back into the groove and align the gap in the front fence to the plate. Glue the fence to the lower base with the fence butting against the upper base pieces. If desired, screw the fence to the base. If you use screws, be sure to avoid the saw blade zone around the zero clearance plate. Once the fence is firmly clamped to the base, turn the sled over to drop out the removable plate, avoiding any glue squeeze out from adhering it to the sled. Clean up as much squeeze out you can now. It will make it easier to finish everything up later.
Build the removable plate and retainer.
Mill a piece of stock for the front and rear bridges to the width and thickness of the gap in the rear fence. Like the removable plate, err on the side of thinner, as the piece can be shimmed with masking tape to bring it flush to the face of the fence. Use a straightedge to ensure it’s at or below the face of the fence. Cut the width of bridge slightly less than the gap so it moves freely up and down in the gap.
Drill the finger hole in the bridge with a forstner bit, then cut the front plate bridge to length.
Drill the finger hole in the rear bridge, then cut the rear bridge to length with the saw blade tilted at 15 degrees.
Cut the zero clearance plate to its final length, 1/32″ to 1/16″ shorter than the slot in the base. You want ample clearance so the plate can move forward and back in the slot, eliminating the chance of the assembly wedging itself between the fences when removing and replacing.
The 15-degree bevel on the remainder of the stock will be used for the retainer, but do not cut it to length yet. It will be easier to perform the machining operations while it is part of the longer piece of stock.
Drill the holes for the T-bolts, then dado a recess for the heads of the T-bolts. Once completed, cut it to length.
The sled serves as the perfect clamping device for the removable plate assembly.
Line both the front and rear gap with waxed paper or packing tape so the zero clearance assembly doesn’t get glued into the gap. Pull the bottom plate rearward against he rear fence, add glue to the rear bridge, then use the sled’s retaining mechanism to clamp the bridge to the plate.
Place a spacer between the front bridge and front fence. I save old hotel key cards to use in the shop. They make great spreaders and also serve as .030″ shims. One of these will work well for this application if you have one. Glue the front bridge to the plate and gently tighten the front hold down as a clamp. Don’t overtighten as the T-Tracks are held into the edge of the plywood with small screws.
Attach the runners
Cut a piece of hardwood to the length of your sled or longer and mill it to a thickness that fits your miter slot. In most cases you will start with a 3/4” board. The board should move freely, but not be loose enough to move side to side in the slot. It’s easy to take too much material off so creep up on the thickness in small increments. A thickness planer works well. Once you’ve dialed in the thickness, use the table saw to cut two runners that are about 1/16” less than the depth of the miter slot in the table saw.
Set your fence so when you place your sled against it, the blade arbor (left side of the blade) is 1-1/4″ from the right edge of the zero clearance plate. The blade should be biased toward the right allowing clearance when tilting the blade 45 degrees on a left-tilt saw. (ask me how I know).
The fence will be the reference when you glue your runners onto the sled.
Place some pennies or washers along the miter slot to raise the top of the runner above the table saw bed.
Put glue on the top of each runner and set them in the slots with the rear of the runner flush with the rear of the table saw bed.
While holding it at an angle above the runners, place the side of the sled against the fence and saw bed, align the rear of the sled flush with the rear of the table saw bed, and slowly pivot the sled downward onto the glued runners. Keep the sled in contact with the fence while lowering it to maintain proper alignment.
Add some weight to the sled to maintain pressure on the runners and let the glue dry.
Install a safety block
The final step in building the sled is adding the safety block. This is an important part of the sled because it acts as a reminder to keep your hands away from the blade area and it covers the blade during normal sled operation.
I used the sled (keeping my hands away from the blade area) to cut a bunch of scrap plywood to size and laminated them, forming the block.
To give some finger clearance for the retaining knobs, cut angles in the top of the block with the band saw. Round over the edges of the block not glued against the fence.
When I test fitted the block against the fence, I thought it should be taller so I added another piece of plywood to the bottom.
Once satisfied with the size and shape of the block, glue it to the back of the rear fence in line with the saw blade. Add a spacer underneath the block so it doesn’t drag against the table saw bed. I used a couple of card scrapers.
Finally, I drilled two holes in the front of the base to hang the sled on the wall.
There you go! The sled is completed. There are still some fine tuning tricks I’ll talk about in Part 5, the final installment in the modular sled base build series.
With the modular sled complete, look for DIYs for individual modules that attach to the sled base. I have plans to add a miter jig, spline joint jig, box joint jig, and a box lid separation jig.
