can anyone tell me the thread rate and the under head length of the pan head machine screw that holds the oil trough on.

the one that feeds oil to the chain. i' m guessing 1/4"  unc may be 3/8 long.  i've made the trough from pics supplied by Ted and its quite trickie lining it up between the cogs.  need to know how deep to drill the block and overcome the dread.

thanks everybody

stuey