After watching the video (
The first thing I realized is that my Forrest WWII 3/32" blade cuts a kerf .105 thick, not .09375. Well, that equats to 3.38 turns of the handle for a blade width instead of 3 turns. Have you tried to turn .38 turns over and over and not lose track of where the hell you are? It ain't easy.
So, plan B is implemented. I load the dado stack and tune with shims to .250. Now all I have to do is cut, turn 16, cut, turn 16, etc.... Yeah right. I built my jig out of 7/8" thick white oak. There is no discernable side to side play in the threads and yet it will not cut joints to my satisfaction. Additionally, If you get lost on your way counting to
16 for the umpteenth time, you have to try and rezero, which means backing up, adding the slop back into the mix and it never comes out right.I was also trying to save time by cutting a set one way then cutting back the other way with another stack of wood. Well, you get used to turning int one way and then find yourself going the wrong direction and losing count on how to get back.
I trashed a pile of good maple today, after having precisely cut and planed it till I got fed up and figured there must be an easier way than this jig. I was fully aware of the indexing jigs with the keyway but most of them only cut one board at a time, are still susceptible to accumulation and slop errors. I wanted something even better.
They say necessity is the mother of invention. I love the simple ideas and should have known that Lynn's jig was too complex. Here's what I came up with, and I've searched the internet and I've never seen anyone recommending this method. Surely it has been thought of before, but I haven't seen it.
I thought, with a 1/4" box joint, I need an accurate way to move WXACTLY
1/2" after every cut with my 1/4" dado. How bout I rip a 1/2" strip of hardwood and cut it into the number of box joints I need so I wind up with 8 - 1/2" strips about 6" long. Realize, when I say I ripped them 1/2", I'm talking 0.500 as measured by my digital calipers. The dado kerf was tuned the same way or it won't work.Ok, I place them all together on my crosscut sled and clamp a stop block to position this stack of spacers EXACTLY on the edge of the kerf to the left of the dado blade so from left to right I have Stop block, 8 1/2" strips, kerf.
Now I clamp 4 box sides together, perfectly flush, jam them HARD against the spacer stack and feed it through the blade. Take out a spacer, jam and cut, repeat till done.
I cut 4 at a time fast, safe, precise and the fit great. This principal could be used for finger joints too. Simple mic the kerf and rip the spacers the exact same width.
Watch ya'll think? I like it. A pic is worth a thousand words: