I tried making some jigs like that a long time ago, but ended up tossing them after I found a better way.
One problem with the router, is that on figured wood, like burls, or fiddleback, the bit will pull little pieces out of the edge.
What I ended up making was a 8' long table saw sled, about 24" wide. It gets a new 1/4" mdf bottom platen every time, so I'm sure it is zero clearance on the bottom.
i may pile 1" of veneers on if they are pretty flat, then lay on a 3/4" mdf for a top platen, then pile on the lead weight, enough to flatten the stack.
I set up a bench in front of the saw to make up a cut, and of course have a long out feed table. I use my best ATB low hook finish blade, set about 1/4" higher than the stack, so I do score to top platen.
I also have some feed rollers out front to make feeding easier.
The only wood i ever had a problem with, was some badly buckled Bees-wing Andiroba, which I couldn't get enough weight on to flatten. I ended up rolling on a coat of epoxy on one side, then clamped the heck out of it between thick boards, with plastic and other thin platens woven in between
After the epoxy hardened, it was like plastic laminate, and stayed flat. I probably could have gotten a good cut with a rip blade then. ha
Hey the idea of lead weights on a table saw sled is great. What kind of lead...? Like plumbers'? Where did you get it? Did you try iron or steel before and find the lead heavier or?
I have done a couple of these router guide deals, all had problems. Here is the perfect solution by Paul Schurch, one of the finest veneer craftsmen in the world. Use a Festool saw with a metal blade. Take off the splitter so you can run the saw backwards along the Festool Guide Rail. I have done this many times on very fragile veneers, the cuts are unbelievable.
Here is another option the MVT. We have been selling these since 2006. They are available for a sliding table saw, table saw and portable circular saw.
It would have been nice if Schurch had continued that video another fifteen seconds to show the results.
I have seen Paul do the Festool joining technique in person and it works flawlessly. Also the veneer trimmer for a sliding table saw is very easy to build yourself... I built mine in about half a day and it works great.
I rough out my veneer on a table saw with a mdf top and bottom sandwich. Then use the same style jig to skim off a sixteenth via climb cut on the shaper, with power feeder of course.
I've done the same thing. And, Matt Seiler and I agree a table saw with a sliding table is much better for this.
But even with an MDF top, a veneer that is not totally flat, (like a burl),or that is wide, will still have less weight in the middle and end up not really tight at the seam....or have those little pieces fly off into the ether.
Creating your own Festool like set up (for those of us who need more $ in our pockets) seems like a great idea. Use a 3 1/2" Circular Saw and make your own jig...put a saw guide fence on the MDF for the CS that you then cut off with the CS.....I'd still have a sandwich of MDF to support the veneer underneath.The Festool guide wasn't long enough for me either.....I am sure going to try the going backwards idea!
A couple of points on the Schurch Festool technique if you try this on your own saw: 1. Variable speed -- the saw is dialed down very slow. Most saws are not variable speed. 2. A metal cutting blade is used (for the rake on the tooth). 3. Long blade guides are available, or shorter ones can be joined