The maximum recommended stylus length for an SM25-1 is 50mm so technically you are exceeding this - but only by approx 5mm (the length of the M3 to M2 converter). I would do some measurement trials yourself to see if you are happy with the results it returns. Try measuring a calibrated ring gauge at whichever orientation you are going to use in your program and see how close a value it returns to the calibrated size. If you have an artifact part that you use for a CMM verification check then all the better. Measure it using your standard probe build and then repeat the measurement using your new one and compare the results.
