I know that this has been discussed before, but since my short term memory is not what it once was, would you please discuss this subject again? What I am referring is the passage in K. N. Harris' book "Model Stationary and Marine Engines", page 133, where he describes the construction and use of "Saddle Keys". May I assume that the keyway in the wheel is broached or filed as usual and the shaft is left plain? Also, as to "round keys", would two 5-40 (5 BA) screws installed 180 degrees apart be proper for a 1/2" shaft with half the hole in the wheel and half in the shaft? Al Messer _______________________________ Do you Yahoo!? Declare Yourself - Register online to vote today! http://vote.yahoo.com MODEL ENGINEERING DISCUSSION LIST. To UNSUBSCRIBE from this list, send a blank email to, modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.