|Forum topic by GerardW||posted 09-23-2013 04:05 PM||631 views||0 times favorited||10 replies|
09-23-2013 04:05 PM
I am working on a new router table top made out of 3/4 phenolic faced ply, which is going to be so much nicer than my current plywood tabletop. I’m also adding in t-track and, pertinent to this post, a mitre channel. For the mitre channel I need a 1 1/8” wide groove.
Lucky for me I just purchased a new dado set (my first!) and figured I could use some fancy shop math and diagrams to figure out a smart way to do this. My dado set maxes out at 7/8” cut, so it is going to be a minimum of two cuts to make this work.
My idea was to use a piece of 1/2” plywood as a secondary fence along my rip fence, and stack the dado up to 5/8”. After the first cut, I would remove the secondary fence, run it through again with the 5/8 set, , and end up with a perfect 1 1/8” groove.
Many of you are already aware of how this story ended. What with 1/2” plywood actually being 15/32”, in the end my groove was off by 1/32”. Searching through my shop with a caliper, I quickly determined that I had no true 1/2” stock in house (I also don’t have a planer to make any). Further, my dado set doesn’t have the flexibility to handle n/32”.
So- suggestions for how to get this groove right on the first try? I of course will practice with scrap wood first to make sure its working, but is there any better solution than running it through once, then jimmying the fence just a tad, running it again… and repeating until its done (or you’ve gone over too far?)
-- Gerard in Bowie MD