The char on the side of MDF after laser cutting is conductive. We’ve tripped the Sawstop on it once before. That case was someone failing to get a laser cut after multiple passes and had a big thick char line which probably reached from the blade to the table or where they held it.
If it’s actually a zero clearance insert, the only cut line would be on the outside perimeter. That should be OK. If it wasn’t and the center was lasered where the blade comes up, it should still be ok because the char doesn’t make a path to the table or where you hand could be, but I can’t say for sure how sensitive it might be.
I got the bulk of the sled done. It’s 36" wide by 18" max bed capacity. It has adjustable spoil boards on the fence, as well as (soon-to-be) adjustable spoil boards/zero-clearance inserts on the bed. The idea is you can close the inserts – fence, and bed – against the blade kerf when you’re dialing it in. And once the kerf clearance becomes a little too sloppy you can simply close the boards together and trim off the nasty bits for a fresh zero-clearance kerf cut.
I put T-Track along the fence and the bed. There are clamps attached to the bed as well. They can be removed with a #2 Phillips in the event that you need all 18" of bed. I “locked” them in hoping to prevent them from walking away when you need them (a la the chuck key problem).
I marked on the front of the sled where you should zero the blade for a good center cut.
TODO:
I need the zero-clearance inserts cut out before I can install them. This will include installing nutserts into the bed (I believe #10-32). I wanted to wait for the cut pieces to do this; since if I made one at home it’s likely to be a little off compared to what will get cut. And I want the nutserts to match the spoil boards/zero-clearance inserts that can be easily reproducible.
The rails need to be installed and squared up. The rear fence is only screwed in, so if you need to move it to adjust it that shouldn’t be a problem. Maybe let me know prior to doing this though.
The whole sled needs to be finished. Sanded down, Shellac on the MDF parts, and maybe oil/wax on the rest?
A stop block would be nice. We can add a home-grown block by using the microjig groove, but it would make more sense to me to just get one off the shelf. The Katz-Moses would be great (maybe he’d donate one?), but I also have that little flippy rockler one that I test fitted on here and it fits fine. There’s just a little bit of deflection which isn’t super desirable. Either way I’m in too deep to throw any more money at this thing, so it’s on someone else
*A Thumb guard would also be nice. I may add one in later unless someone else calls dibs (someone else, please call dibs…)
The char on the side of MDF after laser cutting is conductive.
That shouldn’t be a problem here. We can sand off the char if there are any concerns. Perhaps the only real benefit to using the CNC Router would be to pre-cut the counter sink for the screws. That would save me a pass on a router table.
I’ll leave them on the sled on Tuesday. I’m getting ready to head out of the country, and won’t have time to install them. The Zero Play slides need a couple of nickels for when you adjust them. The only drawback to them is that they are about a foot long. Some sleds have longer miter bars. You’ll also need a 1/2 Forstner bit for the counter bore on the top side. Through hole is 1/4.
The sled is all done, and I got it mostly dialed in. I squared it up with a framing square.
If someone wants to do that whole 5-cut method I’d welcome it. It needs some larger washers for the rails, I have a few bones to pick with the instructions.
