After watching the video (
http://www.netexperts.cc/~lambertm/Wood/lynnjig.html ) I decided it looked
great and fun and so I built one. That is where the trouble started. :)
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,
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:
KISS principal. Gotta love it.