must be full compliment, drawn cup needle bearings. Requires utmost precision in the machining the bearing block, and case hardening on the shaft, but it’s substantially more durable and accurate than a bronze bushing. All the big dollar slide shaft notchers use needle roller bearings. It’s how I made mine.
I’ll take some pictures of mine to show you in comparison. Has a tube capacity of 3.5" and will cut any angle.