I've had a lot of 90 degree angles on these book towers I made for Christmas and this thing worked great. I used this clip to hold my corner and a few more to hold my pieces together tightly when hammering nails - it doesn't get smoother than this.
WETOLS Angle Clamp 2Pcs Woodworking: Precision Tool for Perfect Angles in Woodworking Projects
11 Review
MAXPOWER Piece 3-4-6 Inch
11 Review
TOFL Woodworking Clamping Cabinets: πͺ The Ultimate Storage Solution for Workshop Positioning
12 Review
Multitool pliers LEATHERMAN Wave plus (832524/832526) black
17 Review