Replies

1. 
   oldusty | Feb 03, 2007 08:31am | #1

   ericstand ,

                       Is it possible the angle you need is 31° , not 62° ?

               If I understand correctly a ts with a dado head on an angle may do the trick .

                        good  luck              dusty

1. 
   ericstand | Feb 03, 2007 04:07pm | #3

   The problem is that it really is 62 degrees to the face of the plywood.

2. 
   douglas2cats | Feb 03, 2007 03:14pm | #2

   What's the application? Anything that wide would need a whole bunch of passes whether with a dado blade or router which would be pretty tedious. A real big bandsaw could work, but might not come out perfect depthwise due to blade drift. Could you use pocket screws or biscuits to join the pieces at an angle?

    

   If you build it he will come.

1. 
   ericstand | Feb 03, 2007 04:09pm | #4

   I can't use any joint at that point in the plywood.the stress of sitting on this chair is at the joint and thew stiffness of the plywood is what resists the bendind force

1. 
   douglas2cats | Feb 03, 2007 05:27pm | #5

   Well if I had to do it, I guess I'd make a honking big router sub-base and use a big bearing guided mortise bit. Clamp one piece of scrap ply with a straight edge along the line you want to cut and put another piece on the other side of your workpiece to support the router. Hope you dont have a lot of these to do. That's going to take a lot of passes.If you build it he will come.

3. 
   sapwood | Feb 03, 2007 09:15pm | #6

   The other guys must be quite insightful. From your written description, I simply cannot visualize what you are trying to accomplish. If you could attach a sketch, that would be helpful.

1. 
   ericstand | Feb 03, 2007 09:47pm | #7

   Hi,
   I can't send a sketch, but try and visualize a piece of plywood with a groove, all the way through it, at a 62 degree angle.
   .................... ...................... kind of like this.
   . .
   . .
   .......... ...........................

1. 
   douglas2cats | Feb 03, 2007 11:01pm | #8

   Well I thought I understood what you're doing but after that description I'm not so sure. Is this what you're after or something else?

    If you build it he will come.

   
1. 
   ericstand | Feb 04, 2007 12:17am | #9

   No doug,
   Those dots were an attempt to draw the cross-section of the 3/4" plywood.and the mortise part of the half-lap.

1. 
   douglas2cats | Feb 04, 2007 01:52am | #10

   The dotted diagram looks more like a bridle joint to me than a half lap. Like a 3-sided mortise and tenon with the 4th side completely open? If that's what you're doing, I dont know how you're going to get the slot cut on the female piece with conventional power tools. A band saw would work, but it would have to be a really huge one to fit an 18" panel under it at an angle. A horizontal bandsaw might work. And there's always a hand frame saw. The male part with recesses on both side could still be done with a router jig setup or saw and dado blade. If that ain't it, I'm totally stumped.

    If you build it he will come.

2. 
   ericstand | Feb 04, 2007 05:46am | #17

   Hey douglas,
   Here is a more accurate description of the drawing in question.Please Advise,
   Thanks,
   Eric Stand

   
3. 
   SteveSchoene | Feb 04, 2007 01:55am | #11

   I'd like to help, but I've been reading and still don't have a clue about what is wanted.   The term half-lap doesn't register to me in this context, since the in usual meaning there isn't a "mortise part", each piece is rabbeted to half its depth, and the two are thus overlapped. 

   Maybe some additional description might help.  What kind of chair are you making?  What two pieces are being connected together?  You have said that one is 18" by 36", but what is the size of the other.  Is it also plywood?  What other pieces are being used?  Is there a picture of what you are attempting to make somewhere on the web that we could look at? 

4. 
   ericstand | Feb 04, 2007 05:30am | #14

   Hello Steve Here is the drawing for the part in question.
   I hope this paints a more accurate picture.Thanks,
   Eric Stand

   
2. 
   sapwood | Feb 04, 2007 04:07am | #13

   I'm still a bit uncertain about what it is that you are trying to do and in what material. But, I'll take a guess...... why not?.... there are no points off for guessing.If the angle were 45º then I think the cut you want to do could easily be done by tipping the tablesaw blade over and cutting away. But, you want 62º and the saw won't tip that far. So.... why not build or modify a crosscut "sled" that will tip the work piece 17º and also tip the blade 45º to give a combined angle of 62º? Does that make sense? I get the sense that the dado you want to cut is of the stopped variety, in fact, stopped on both ends. In that case you will have to raise and lower the blade through the work. You might want a helper for that operation. An overhead router might also be a way to do this. But I'm not sure there, my overhead router experience is limited and dated.

1. 
   ericstand | Feb 04, 2007 05:44am | #16

   Hey Sapwood,
   Here is a more accurate description of the drawing in question.Please Advise,
   Thanks,
   Eric Stand

   
1. 
   sapwood | Feb 04, 2007 07:25am | #20

   Tilt a bandsaw table and block up a ramp for the remaining slope. Cut in twice. chisel out the end. Lacking a bandsaw..... make a guide block and use a handsaw.

4. 
   eddiefromAustralia | Feb 04, 2007 02:20am | #12

   Hi Eric,

   Reading really quickly through the answers and your responses, are you talking about running a groove into the cut surface, so that you can run a loose tongue and groove to hold the thing together?

   The cut surface is at 62° to the outside face of the ply.

   Is this what you refer to?

   Cheers,

   eddie

1. 
   ericstand | Feb 04, 2007 05:32am | #15

   Hey Eddie,
   Here is a more accurate description of the drawing in question.Please Advise,
   Thanks,
   Eric Stand

   
1. 
   eddiefromAustralia | Feb 04, 2007 05:55am | #18

   Hello Eric,This looks like hand tools to me for a one-off.It could be cut using ramps and jigs, but there'd be more time in making the jig than in cutting the joint.Cheers,eddie

1. 
   ericstand | Feb 04, 2007 06:05am | #19

   I need to make at least twelve of these, and if they are popular, then find a CNC shop to mass produce them.