sagreen83
07-02-2007, 01:18 PM
I'm sure that others have figured this one out in the past, but it was a god send for me...
I am in the process of making a large run of Quarter Sawn white oak, "Mission" style dining chairs. Like all other chairs there are a lot of angled mortice and tennon joints in the construction of each chair. So the joint uses a floating tennon, and angles the mortice in the end of one of the pieces, in this case the legs. These mortices are cut at an 85.5 degree angle from the face. I tried EVERY manual way that I could think of. First I tried to build a tilted jig to place in my benchtop morticing machine. Problem was that the oak is super hard and caused flex in the machine making the angle greater than I wanted. So, I ditched this idea, and moved to a tilted jig with router guides to manually plunge at router into the mortice. Problem was that this was super sloppy. Then I moved to what I am now calling my "Manual Shopbot" where I build a slide that attaches to the tilted jig with ball bearing drawer sliders. This actually worked the best of all "Manual" methods but was still a bit sloppy for my tastes.
So, out of ideas I sat down and thumbed through my Woodcraft magazine looking for ideas. I ran across these angle vises. http://www.woodcraft.com/family.aspx?familyid=4353 They are intended for use in a drill press, and the idea is that they are a standard drillpress vise that will tilt to any angle. I thought, hey these are cheap enough, I'll buy 2 of them. Got them to the shop, and mounted them to a piece of 2'x2' plywood registered to 0x0 in my bot. I placed the vices so that they were exactly spaced to the ends of the pieces that I was working on so I could flip the piece end for end to do the other legs. The trick was finding the center of the piece after it was tilted. But, after I got this all dialed in, I could cut precise angled mortices every time, and in a fraction of the time that I was doing it by hand.
If this is not clear, I can post a photo of the jig.
The next thing that I want to do is figure out a way to incorporate a X, Y and Z zeroing portion of the jig to automate this process as well. Another feature that I would like to incorporate into this design is T-tracks so that I could place the vices differently to hold other parts. Right now the jig will only really work for the chairs, but I expect that I will use this for a lot more projects even if the part is not tilted.
Scott...
I am in the process of making a large run of Quarter Sawn white oak, "Mission" style dining chairs. Like all other chairs there are a lot of angled mortice and tennon joints in the construction of each chair. So the joint uses a floating tennon, and angles the mortice in the end of one of the pieces, in this case the legs. These mortices are cut at an 85.5 degree angle from the face. I tried EVERY manual way that I could think of. First I tried to build a tilted jig to place in my benchtop morticing machine. Problem was that the oak is super hard and caused flex in the machine making the angle greater than I wanted. So, I ditched this idea, and moved to a tilted jig with router guides to manually plunge at router into the mortice. Problem was that this was super sloppy. Then I moved to what I am now calling my "Manual Shopbot" where I build a slide that attaches to the tilted jig with ball bearing drawer sliders. This actually worked the best of all "Manual" methods but was still a bit sloppy for my tastes.
So, out of ideas I sat down and thumbed through my Woodcraft magazine looking for ideas. I ran across these angle vises. http://www.woodcraft.com/family.aspx?familyid=4353 They are intended for use in a drill press, and the idea is that they are a standard drillpress vise that will tilt to any angle. I thought, hey these are cheap enough, I'll buy 2 of them. Got them to the shop, and mounted them to a piece of 2'x2' plywood registered to 0x0 in my bot. I placed the vices so that they were exactly spaced to the ends of the pieces that I was working on so I could flip the piece end for end to do the other legs. The trick was finding the center of the piece after it was tilted. But, after I got this all dialed in, I could cut precise angled mortices every time, and in a fraction of the time that I was doing it by hand.
If this is not clear, I can post a photo of the jig.
The next thing that I want to do is figure out a way to incorporate a X, Y and Z zeroing portion of the jig to automate this process as well. Another feature that I would like to incorporate into this design is T-tracks so that I could place the vices differently to hold other parts. Right now the jig will only really work for the chairs, but I expect that I will use this for a lot more projects even if the part is not tilted.
Scott...