Seems like hidden pins.
As JDW mentioned, keep in mind beforehand the final profile of the scales. IOW, keep your pins short enough.
Keep some scratch paper and pencil nearby, use a drill stop and caliper, and all will be well.
No special glues that I know about. Common epoxies work well.
The main thing to worry about is maximizing surface area for the bond, so don't overlook scuffing, or better yet grooving, the tang.
Matter of fact, the last one I did with hidden pins, I used hardwood dowel for the pin material. Since the scales were also wood, I felt the wood-to-wood bond was stronger than using a metal-to-wood arrangement. This is a kitchen utility that gets used daily; no problems yet.:shush:
I've also used 1/4" tubing with slits cut in it to allow more contact area for the epoxy. Standard solid pins with grooves would probably work just as well.
I feel the grooves in the pin are most certainly worth it, but one has to become intimate with a magnifying lens and small needle file; a thin cutoff wheel in a Dremel used with a light touch would also suffice instead of a file.
My best results have been attained by grooving the pin perpendicular to the pin axis, and having the groove at a slight downward angle (towards the tang).
Using this method, I cannot detect any difference in reliability vs. using a full-length pin. It just takes a little more time to do it. But done properly, it's worth it for aesthetics alone.:biggrin:
Good luck,
Robert
