Cutting sawdust relief in sled

Question

I have a sled that I want to add a sawdust relief slot to:

That’s an unsurprising side view. It’s about 24” wide. I want to cut a slot at the red thing. The shape doesn’t really matter as long as one side of is flush with (or beyond) the fence. The size doesn’t really matter either. However, I do not want to cut into the bottom of the fence itself, as I use this sled for very thin materials sometimes.

I feel like this is obvious but for some reason I can’t think of an answer: What’s an easy way to cut this?

• I don’t really have any way to get in there with the router.
• The fence is too high for me to prop it up and cut a dado on the table saw and also that’s super sketchy.
• I don’t really have any hand saws that can get in there given the 24” width.
• The fence is taller than the flat part on my chisels.
• I can’t remove the fence because it’s glued on to the base.

All I can think of is carefully, slowly, and painfully coming at it with a thick-ish cutting disk on a Dremel. Is there a better way to do this?

The fence is plywood, the base is mdf.

Like I said, this might be obvious, but I’ve been huffing xylene all day so I really have no idea.

Answer 1

Take a blade out of a hand plane, press the back flat against the fence and run it along the width of the sled several times, creating a vertical cut into the base. Then come back and use a chisel to create the other side of the notch.

Alternately, instead of using the flat side of your chisel against the fence flip it over and index the bevel against the fence. It's not as big a surface, but with a large chisel it should be easy enough to feel when it's tight against the fence.

Another idea, if you don't have any hand planes, would be to take a blade out of a hacksaw, press it against the fence and work it back and forth. I think this would be pretty slow though, as the teeth for cutting metal are very fine. Other possibilities would be a ryoba blade, a reciprocating saw blade, or a jigsaw blade. I might put a piece of masking tape on the fence to account for saw tooth set and prevent it from being scratched.

Answer 2

If you have an oscillating tool, the cutters that are part of such kit will do flush cuts.

I would not use the o-tool, even though I have one, as this particular objective lends itself well to a simple (sharp) wood chisel and mallet.

You can drive the chisel straight down at the fence edge, along the entire width and return with the chisel held at a slight angle to the base of the sled to remove a clean V-shaped groove. If you require more depth or more width, it is easily adjusted with additional passes. A flat bottom groove is a simple matter of yet a few more passes.

Answer 3

There are two easy ways to do this:

1. You can do this easily with a knife alone, or knife and chisel. Basically you set it up like a "first class saw cut" or in Paul sellers terms, a "knife wall" - just deeper than you'd normally go.

The key is starting shallow and going progressively deeper as you remove chips. The vertical part of the groove (continuation of the vertical fence line) you cut with a knife. Then come it at an angle for the angled (obviously!) part of the groove - that can be either with the same knife or with a chisel. The chisel will be more solid and easier to control than a knife, but a knife could do it, just perhaps a little sloppier. Then remove the chips. Scribe and pare, going successively deeper with every pass. You could go all the way through if you wanted, thereby forever eliminating the need for saws ;)

2. Remove the fence, then run the panel upside down over the table saw to create a very shallow dado in the right location.

Answer 4

I can’t remove the fence because it’s glued on to the base.

This seems to be the major impediment to getting the job done. The right solution is to remove the fence. The other options are all hacks to get around the apparent immobility of the fence.

There are plenty of ways to remove a glued part. Depending on what kind of glue you used, any of the following can work:

• A few solid blows from a stout mallet.

• Heat.

• Solvent.

• Cutting along the glue line, or right next to it.

For example, if the sled doesn't extend behind the fence, then you can put the back of the fence down on your table saw with the bottom of the sled running along the rip fence. Set the blade height to the thickness of the sled fence plus 1/8", and cut through the glue line. Then just attach the fence to the sled again. The extra 1/8" will give you a shallow 1/8"-wide channel in the sled surface to catch sawdust.

If you go with one of the other methods, you'll need to clean up the mating surfaces before you replace the fence. But the fence and the sled are both wood, and you're a woodworker!