I have a Johansson Model A37 Ser. 5254 The plate says Johansson & Windle Chicago, Ill. For all practical purposes it looks like the Clausing 8520. It came with an assortment of collets - couple of #2 MT and some marked #7 which I assume are B&S. They vary in length from 2 7/8" to 3 1/6" so most are pulled way up in the spindle and the longest(unmarked) protrudes about 1/4". Are the B&S and The Morse interchangeable? I didn't think so but the seem to work. I want to buy a new set but I can't decide on which one !! The Clausing drawings list both. Thanks for the help