Can anyone please help me. I am looking for ideas on how to make a jig to use with my bandsaw for cutting Finger Joints.
The fingers are 3″ deep and 6″ wide and upto 8 fingers on each joint, The length of timber is up to 12′ long so conventional methods (table saw and router are out of the question – height restriction in the shop) , I have more than 250 fingers to cut, so the traditional hand method is not preferred.
I noted that there was an article in Fine woodworking (#39), but this is no longer available.
So any brainwaves – would be appreciated – repeatability and accuracy are essential.
Replies
Manipulating a 12' long and 6" wide board accurately enough to cut finger joints at the bandsaw sounds pretty tough. How thick are the boards? If they are 3" thick, as suggested by the 3" long fingers, that's a heavy board and a cut depth that limits your options.
If you really can handle the stock on the bandsaw, all you would need for the jig would be a rip fence, stop block to limit the cuts, and a set of spacers to effectively move the fence over for each cut. With that many to cut, it would be worth making spacers of the correct dimension. I suppose if you used a roller stand to support the end of the stock not on the table, you could mark the roller to show where the workpiece should be to cut straight with each spacer.
Hand cutting these might be a reasonable option. But some sort of jig would help, whether you use hand or powered tools. For instance, a precisely dimensioned template clamped to the board so you cut the fingers from the side with a router might work, if the board thickness were no more than double the cut depth, or you were willing to complete the cut later. A template something like a miter box that clamped to the workpiece could guide a handsaw, jigsaw, or other saw.
A drill and chisel would likely be needed with any of these approaches.
Thanks for the reply
The in-feed and out-feed of the bandsaw is not a problem - The lumber is 6" * 6" down to 6" * 1". The Toungs are upto 6" wide and 3" long and 1/2" thick.
The drilling out and chiseling was expected, I can use my mortising machine for this - it was just the huge number of shoulder cuts (Thousands) that was stumping me. I tried the method you have suggested, using spacers, it was not just not accurate enough and I was looking for some form of jig, that I could also use again in the future, should the project be repeated.
Of course the easiest would be to have a verticaly (movement) mounted DADO - or a 20' high celing - unfortunately neither of these optionas are available.
again thanks for the suggestions - Tony
Two suggestions:Radial Arm Saw and dado blades, with the blade rotated to the horizontal. Spacers under the timbers pulled out one set at a time to adjust the height. If there isn't enough height between blade and table rotate the saw until the arm points out the back and build a table to suit.Make a jig to use a Circular Saw and a rip blade if you can find one to fit. Probably want an 8 1/4 to get the 3" depth. You also have the option of trying to tilt the blade to cut out wedges to simulate the joints cut with a Shaper. That would eliminate the need to drill/ mortise too.What on earth are you making?
Actually the router method may not be out... I recently saw a jig for use with wide panels. Essential you moved the whole jig for each cut. It would align itself from the last cut. It was in a friends router book, and I can not remember the name of it at this point... but it was along the lines of "Router Jigs"...
Essentially it was a T shaped jig. The router would slide back and forth across the top of the 'T', and the bottom would hold it perpendicular to the wood. Of course there was an alignment pin to adjust from the last cut.
Buster
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