Pretty cheap bits. I used 3/4" to cut the T-track slot. The slot was too small so I measured with calipers and got 0.736". Can actually be used as a decent little plywood nozzle if you want something extra Slop in 23/32" (.719") plywood. For the price I can't complain but if I could do it again I'd recommend just spending the money on a quality set of straight bits.