In my Hands On Review of the Laguna Revo 1836 I noted "There is no way to lock that button so that one can use both hands to perform a task. It would be nice to have a plunge pin that would hold the button in and the spindle locked." I commented that I might end up drilling a hole and inserting a pin to hold the spindle lock engaged. In fact, I did do that shortly after writing the review, but I failed to post a follow up.
With some new interest in the Laguna I thought I would share my fix for this minor issue. It is quick and simple. I used a straight edge across the front of the headstock and measured the depth of the spindle lock button when engaged. I then marked and center punched on the front surface of the headstock the location for a pin. The hole was drilled with a 9/64" bit (as I recall - probably should check that.) I then cut off a 10D finish nail to use as a pin.