Alex Horvath
12-28-2010, 12:58 PM
Hi,
I just made my first 6 mortise and tenon joints using the Jet benchtop mortiser and Delta table saw tenon jig. About half of them are near perfect but the rest have noticeable offsets. I turn the work piece to cut from both sides on both mortise and tenon for perfect centering. Also, there was enough variation in the mortise width that I had to sneak up on my tenons to get a tight fit.
I checked the fence and bit on the mortiser for square to the table and they look good.
Also checked the tenon jig for square to the table saw.
Here are my observations-
1. I noticed that if I'm not real careful, chips get between the work piece and mortiser fence which of course really throws things off.
2. I seem to have a hard time getting the mortiser chisel aligned to the work. I can clearly see the uneven sides of the mortise. I suppose this is not a big deal if your spacing of cuts is consistent but going back to clean up with multiple passes will have the effect of enlarging the mortise.
I think #1 is my biggest problem, obviously the mortises were not perfectly centered since the tenons are more likely to be perfectly centered (stock is verified same thickness). I suppose it's just a matter of keeping the work tight to the fence at all times.
Sneaking up on the correct tenon thickness is not too time consuming for say a dozen or less joints but more than that will get tiring.
Also, I nibble the shoulder cuts with table saw but this also can be error prone and very tedious. I suppose if you are doing lots of joints you could set up a dado with a gauge block on the fence.
Thanks for any tips.
P.S. I read once that even production shops generally run frames (mortise and tenon or cope and stick) through a wide belt sander to get the joints in perfect alignment. They have to come back and hand sand the cross grain scratches on the rails. Hand sanding a misaligned joint will show in low angle light unless you feather it across a long distance.
I just made my first 6 mortise and tenon joints using the Jet benchtop mortiser and Delta table saw tenon jig. About half of them are near perfect but the rest have noticeable offsets. I turn the work piece to cut from both sides on both mortise and tenon for perfect centering. Also, there was enough variation in the mortise width that I had to sneak up on my tenons to get a tight fit.
I checked the fence and bit on the mortiser for square to the table and they look good.
Also checked the tenon jig for square to the table saw.
Here are my observations-
1. I noticed that if I'm not real careful, chips get between the work piece and mortiser fence which of course really throws things off.
2. I seem to have a hard time getting the mortiser chisel aligned to the work. I can clearly see the uneven sides of the mortise. I suppose this is not a big deal if your spacing of cuts is consistent but going back to clean up with multiple passes will have the effect of enlarging the mortise.
I think #1 is my biggest problem, obviously the mortises were not perfectly centered since the tenons are more likely to be perfectly centered (stock is verified same thickness). I suppose it's just a matter of keeping the work tight to the fence at all times.
Sneaking up on the correct tenon thickness is not too time consuming for say a dozen or less joints but more than that will get tiring.
Also, I nibble the shoulder cuts with table saw but this also can be error prone and very tedious. I suppose if you are doing lots of joints you could set up a dado with a gauge block on the fence.
Thanks for any tips.
P.S. I read once that even production shops generally run frames (mortise and tenon or cope and stick) through a wide belt sander to get the joints in perfect alignment. They have to come back and hand sand the cross grain scratches on the rails. Hand sanding a misaligned joint will show in low angle light unless you feather it across a long distance.