Nikki - diggin' the new sig.
Not sure I'll be of any use - my bk24 didn't come with scales. I wound up using 8-32 stainless hardware in the one I built. I'm going home early today, so I'll double check which wrench I use.
Do you know if you have #10, #8 or #6 threads? #8 (Tweener) should use 9/64, and #6 standard is 7/64. #10 (Full-Size) uses 5/32.
I got a Bondhus Gorilla Grip fold-up allen wrench tool. The yellow one in US sizes has a key to fit any/all of my Beckers.
I assume you're talking the factory Micarta scales. Someone who has mounted those should be able to chime in soon.
Or PM Bladite to see if he can add it to the Database. Most H/W is in there, and it mentions BK11 Factory Micarta, but I don't see a listing for Hardware for the factory scales on the Necker or Eskabar.
To keep it On Topic: As stated above, the full-sizers take 5/32 - that's the standard for both #10 and #12 hardware. 5/32 = .15625. 4mm = .15748. Guess that's why the 4mm is more snug. But it's a made-in-USA Becker. Who's sticking metric tools in there???
Not to mention putting a Torx key in an Allen socket, but hey, if it works - it works!