I made a jig that can accurately process dowel hole.
Dowel hole jig using parallel link. Regardless of the thickness of the workpiece, you can open a dowel hole in the middle.
There is a similar youtube movie, but because there is no adjustment function jig accuracy will depend on the work precision. Therefore, I tried to improve the structure that can be fine-tuned.
Thanks to the adjustment function you can make dowel holes that match exactly even if the processing accuracy is bad.
1) In the movie, the adjustment is done with screws, but it turned out to be shifted when hard wood was processed. So I think that it is better to bond them.
2) When using a drill for woodworking, the torque is large, and distortion occurs due to insufficient rigidity of the jig. Perfectly matched dowel hole does not open.
I improved using iron drills.