Table Saw Sled With Miter Accessory

I wanted a dual purpose miter sled to build a project that required exact miters for the mirror frame and perfectly square shelf ends for sliding dovetails.

What I came up with combines both functions in a simple design that is fairly easy to build.

I hope this build gives you some ideas for your own sled as other maker's ideas contributed to this project.

1. Two pieces of 24”x 24” x 3/4” MDF (Home Center)

2. One piece of 2 x 4 x 30” (Home Center)

3. One piece of T track, 36” long (Rockler)

4. Two T track clamps (Rockler)

5. 8 pieces of 8-32 x 1/2” nylon tipped set screws. (McMaster Carr)

6. Planer

7. Table saw

8. Jointer

9. Drill press

10. Shop tools

Cut the MDF in half then square the sides and ends.

Lay out the size of the miter insert accessory, leaving room at either ends for material support. Also determine where you want the T track and access holes. I positioned the two halves against the blade for correct spacing.

With the fence on the right side, position it so the MDF is located just into the blade by 1/16”. Then mark the table saw slot location on the edge of the board. Label the board “right side top”.

With the fence positioned on the left, repeat the process. Label the board “left side top”.

Cut the front and rear rails to size, joint and plane both to 3” heights. I didn’t think making the fences fancy would lend to better utility so I chose not to. I may add a track to the top of the front fence in the future for a board stop.

Cut the runner dados on the bottoms aligned to the marks.

I made my runners out of oak which is very durable. You can use any runner that suits you, just size the dado accordingly. I stopped mine short of the full length because I have a roller out feed table. I added five countersunk screw holes for mounting later.

I aimed for a very snug fit because they won’t be mounted until the end. There are more operations that require them to be removed for further modifications.
I also found that working with MDF, I try to screw fasteners in once as the material will pull up inside the pilot hole making it difficult to remount.

With the runners fitted, not mounted, trim the excess from both sides to create the blade slot.

Keep in mind you need to keep pressure on the runners towards the outsides, away from the blade as you cut.

Create a blade spacer to keep the distance the same during the fence mounting operations. I used a cut-off from making the runners and planed it to the blades thickness using double sided tape and planned flat stock as a sled.

Next, using a forstner bit, drill the T track bolt access at the end of the track layout marks. I used a 3/4” router bit with a dado guide to cut the track slots. Mount the T tracks.

Determine the location of the front fence and layout equally spaced mounting holes. I used three screws per side for stability. Countersink and test holes for a flush, below bottom fit using the mounting screws. Repeat for rear fence.
With the two halves mounted on the saw, insert the blade spacer and verify the two ends are flush to each other.

Overhang the two pieces at the back of the saw and clamp rear fence in place. Using a square and the blade insert, adjust the fence until perfectly square to the cut. Clamp tightly, drill pilot holes and drive the mounting screws in place.

Slide the sled to the front and repeat the process. Pay close attention to squaring the fence face, adjusting and verifying each side in relation to the blade insert. Drive a screw in one end, check for square. Drive another screw in the other end and check for square. Paying attention now will pay off later so you won’t need to drill new holes for an out of square fence.

In this step, I added 8-32 x 1/2' nylon tipped set screws. The purpose of these are to take up any play in the runner to saw slots that may be introduced in the construction of the sled. I installed them facing in the direction of the blade to allow for wood expansion/contraction.

Remove the spacer and flip the sled over. Scribe a pencil line along the runners where they meet the base. Mark with an arrow the direction of the blade on each runner. Label each side L or R and remove

Scribe a pencil line half the distance from the bottom of the runner and the scribed previous line. This is the center point for the set screw holes. Divide the length with four equally spaced marks along the center point line.

To determine the size of the drill to use for the 8-32 set screws, I tested different drill sizes in a piece of test scrap of the same material as the runners. I started with the recommended #29 and settled on a #31.

Be certain to set up the drill press to drill perpendicular to the work piece. I bolted a drill vise to the table to accomplish this. I tapped the holes with a started tap in the direction of the arrows, towards the blade. I did this to have tapered threads at the end where to tip will meet the saw guide. The extra friction will help retain the screw once set. Install the set screws slightly proud (Approx 0.005")

Reinstall the runners, drill pilot holes and mount them permanently. Test the fit on the table saw. Sliding back and forth should feel smooth, with no grabbing. Use pencil along the runners to see where it is rubbing.You may need to sand the runners a little to achieve a smooth slide. I glued a piece of sandpaper to a flat block for this. Once the sled slides nicely, check for side to side play. If there is any play, this is where the set screws come into play. Adjust the screws on one side about a 1/4 turn each and test again. This may take a bit of time to accomplish, well worth the extra time when the sled works properly.

Finally, I used some bees wax to lubricate the runners and bottom of the sled.

Perform a five square cut test. This involves cutting a fairly large piece of scrap five times. First, cut one side on the newly squared fence and mark it cut 1. Bench that cut on the fence and cut the other three sides, rotating the piece back to cut 1 when finished. Cut a one inch strip and measure the top and bottom width. The difference should be less then 0.003” per 12”. Here is a link to the calculation: http://valleywoodworkers.org/wp2/wp-content/uploa...

If the measurement is out of spec, you may need to remount the fence or accept it as it is. A little bit out of square should not affect the miter cuts.

I used the other 24 x 24" piece of MDF to make the miter gauge.

First, cut the piece to the width and length you decided on in step one. Cut the length and width a little oversized as you will need to trim it to final size later, I used a standard miter gauge with an auxiliary fence squared to the blade to make the first 45 degree cut.

Now you get to use your new sled to make the next cut!

Bench the 45 against the fence, lining up the end of the 45 to the sled blade opening. The remaining piece will be roughly the final size of the miter gauge. I used the point of the triangle, centered on the blade opening to determine the amount to be trimmed for an exact fit on the bottom length.

Determine the location of the T track and drill mounting holes approx. 2/3's the distance from the fence.

Install the T bolts and nut handles with the center of the triangle in the blade opening. Raise the blade about 1-1/2" above the sled and cut a slot part way into the miter gauge. Lower the blade to 1/4" above the sled and cut the full length of the miter gauge.

Remove the gauge. Using the the blade spacer you made earlier, make a spline to fit in the slot, approx 1/2" proud. This will keep the gauge perfectly aligned when reinstalling it on the sled.

Make some test cuts and using a small rafter square, check for a good 90 degree fit.

Nice thing about the gauge is you can add a fence to it later for mitering tall parts.

I made mine for a mirror frame that is only 5/8" thick so I didn't add them at this time.

This is my first publication so I'm sure there are some mistakes, but I hope you can get some good ideas for your own sled.

Enjoy, however you make it!