Box/Finger joint question for Casey4s

[macdillard]

Casey, a question about your Finger joint jig...To make one of these jigs work correctly the face of the backing board(where the pin is mounted) must be perpendicular to the miter slot slide..(hope that makes sense). How did you install the miter slot side such that it is perpendicular to the backing board? (or do you have the jig mounted on the miter gauge.) Hope that is not a trade secret.

By the way, got to try out the Table saw finger joint jig I got from Sears and it works very good..That is once you get it set up. Set up to adjust the thickness of the fingers is true trial and error. You have to move the whole rig where it is mounted on the miter gauge by hand. My Router jig is set up such that this adjust is by a fine thread screw and sets up really quick.

[Casey4s]

I got a little confused at the question But... here's some more pics. You can see how the bottom is constructed and uses side rails to keep the jig on course. If this doesn't help, just post another question here.







Here's the rest of the pictures
Box Jig pictures by Casey4s - Photobucket

[macdillard]

Think I have it now.You don't use the miter slot.You do nice work. That looks really good. My Router Jig was made from scrap and it looks like it..But it works.

[Casey4s]

I just shot another video this shows the cutting better I think. I don't have any drawings because I built this "on the fly".

To see this video, Click on the pic

[Casey4s]

When I cut the slot in the jig for the cutter, I had the botton constructed so I just raised the router up until it cleared then moved it to cut that slot. Then I attached the back fence and supports.

I used plywood for the bottom that I laminated in plexi-glass onboth sides, so it will slide easily and it's easier to keep kleen. The back board has plexi on the cutter side only.

[Casey4s]

........works very good..That is once you get it set up. Set up to adjust the thickness of the fingers is true trial and error. You have to move the whole rig where it is mounted on the miter gauge by hand. My Router jig is set up such that this adjust is by a fine thread screw and sets up really quick.

That's whay i don't like dado blades. Mine takes almost no set up time at all and it cuts really fast.

[imaradiostar]

I've just spent a bunch of time looking for a thread I participated in a while back but I can't find it. I once made a jig similar to this- it worked great for smaller cabs (less than 10" deep) but when the time came to make a cab 12" or 14" deep it became problematic. It has to do with the tolerance of the cuts- unless it's dead on to the thousandth of an inch, when you get to the end of a wide board you can't guarantee that the slots are consistent. You'll get the sum of the tolerances at the end of the board and things may not fit together correctly. It may not happen all the time but it will happen eventually and it's very frustrating to have to scrap your work! Perhaps this was a reflection of my own skills, I dunno. I wanted a solution that was "Jamie-proof."

The fix is to use a comb/jig that has pre-cut slots that are precise- this way the max it can be out from one end of a board to the other is the slop of a single joint. This applies with both router and table saw based systems. I've successfully used my jig with a table saw (with dado blade) and I've had excellent results. I feel that once it's set up correctly a table saw does a great job but I have the luxury of sharing a shop with my dad so my saw is set up for finger jointing and his is for normal cuts.

here's a link to a thread with something similar using a router:

http://music-electronics-forum.com/t3880/

Here are pictures of mine:



The comb indexes with the sled using the unthreaded portion of a metric M8 bolt- a nice snug fit. The jig is made of leftover baltic birch scraps from a few 60"x60" sheets a friend and I bought for making guitar cabs. I've had none of the aforementioned trouble with this jig- all boards have gone together cleanly with no forcing and even glue space across the whole depth of the board.

Keep in mind- I'm not knocking the aforementioned method, just sharing something that has helped me. Good luck, work carefully!

jamie

[Casey4s]

My jig as it is only cuts 1/2" boxes, but I can adapt it ot cut 3/8" and 1/4" if I needed to. The 3/8" might be interesting to work with but I have no need (at this point) to do 1/4".

[Casey4s]

This video shows cutting two identical boards at the same time.

Click on the pic to see the video


And this video is cutting through a really hard KNOT in a piece of wood. Most people would avoid a knot this large in a finished piece, but smaller knots are sometimes hard to avoid.