As RDG where out of stock I bought one from Chronos Boxford size made by Soba , the tool holders are 73x32x30 and take 16mm tools , the heighest the holder will go is 25.5mm from the base to the bottom of the tool , on my lathe a 1\4" tool leaves a small pip , the largest that the base can be bored out to fit your boss is 1 1\2" , hope this helps .