I use the 45 degree lock-miter bits a lot. I believe Randy's right - the set-up blocks are definately worth the money ... good point to start from and they'll save you time, but they only get you close.
I also believe Woodnut65 is right - save the final perfect test piece as a set-up block - BUT IT'S ONLY GOOD FOR THAT EXACT SAME MATERIAL ... which is the same reason the set-up blocks can only get you close. It's the minute differences in material thickness that get ya.(By the way, if you're going to make your own setup block, once you've got it adjusted, actually use a thicker piece of material to save - it helps to have a vertical edge to set the fence against).
In general, for height, on the flat piece, you want the upper mitered bit edge to hit right at where your material thickness intersects the fence face, and for fence distance you want the lower mitered edge to hit right at the outside material face at the table surface of the verticle piece. Another way to look at that is that the spline is centered, but the exact center is hard to establish, both on the material and on the cutter. I use the set-up blocks to start and then adjust closer by laying a straight edge along the material and raising the bit or sliding the fence.
As you get close it can also become difficult to tell if you've gone too far because your shaving down to a mitered edge - I'll take a pencil and just lay it flat and run it along the material corner to leave me a colored edge to see.
But in the end, at least for me, it's still adjusting by eye and running a few test pieces to get it perfect. On a good day, it usually takes me 2 or 3 trys.
If somebody's got a less painful or more exact way, I'd really like to hear it - I've had no instruction, and have just sort of bumbled into doing it this way. The first time I used that bit, I almost ended up yanking it and throwing it against the wall (Instead I went inside, had several scotchs and called it a day) - but now I love em and it's gotten easier with practice.
I also believe Woodnut65 is right - save the final perfect test piece as a set-up block - BUT IT'S ONLY GOOD FOR THAT EXACT SAME MATERIAL ... which is the same reason the set-up blocks can only get you close. It's the minute differences in material thickness that get ya.(By the way, if you're going to make your own setup block, once you've got it adjusted, actually use a thicker piece of material to save - it helps to have a vertical edge to set the fence against).
In general, for height, on the flat piece, you want the upper mitered bit edge to hit right at where your material thickness intersects the fence face, and for fence distance you want the lower mitered edge to hit right at the outside material face at the table surface of the verticle piece. Another way to look at that is that the spline is centered, but the exact center is hard to establish, both on the material and on the cutter. I use the set-up blocks to start and then adjust closer by laying a straight edge along the material and raising the bit or sliding the fence.
As you get close it can also become difficult to tell if you've gone too far because your shaving down to a mitered edge - I'll take a pencil and just lay it flat and run it along the material corner to leave me a colored edge to see.
But in the end, at least for me, it's still adjusting by eye and running a few test pieces to get it perfect. On a good day, it usually takes me 2 or 3 trys.
If somebody's got a less painful or more exact way, I'd really like to hear it - I've had no instruction, and have just sort of bumbled into doing it this way. The first time I used that bit, I almost ended up yanking it and throwing it against the wall (Instead I went inside, had several scotchs and called it a day) - but now I love em and it's gotten easier with practice.
