Description of π Climax Metals TC 038 10 Drill Center: High-Precision Tool for Accurate Drilling
Centers have both external & internal points for marking exact drilling location. Provides for precise alignment of dowels & tenon joints. Steel construction with zinc plated finish. Item Package Dimension: 0.375" L x 0.375" W x 0.375" H
They fit 3/8" dowel holes. I use them to transfer dowel holes onto a custom coffee table I made for a client. This is practically the only way to accurately transfer the dimensions of the dowels to a flat surface.
They are a little pricey but they make up for it with the accuracy and ease of use of the products. If you take your time you will achieve near perfect alignment between the dowel holes, just make sure the two boards are aligned and centered before installing the holes.
Pros
Centers have both outside and inside dots to mark exact drilling location
I have never used dowels before so decided to try all the tricks for my credenza project. These dowel guides helped me align the dowels much more accurately than I could otherwise. I needed at least 6 packs for a joint, so a 10-pack was just right. I don't know what else to say, they were clean in the holes and left good tracks. You worked for me!