I'm wanting to HC my 319. When I was down at Glen's we figured out how it could be done. I was just curious to know if he actually did it with his yet. The 319 does not have enough room for both a spoke wheel and a HC. The balance wheel has to be modified to accept the HC. Neither of us wanted to cut away the balance wheel of the 319. But we figured out we could take a balance wheel off another machine and notch or put in a metal piece to hold the HC arm in place. Putting in a piece of metal does require tapping a screw hole in the balance wheel to hold the metal on.
http://www.treadleon.net/sewingmachi...k/fwcrank.html here is something I found. You do not have to build up the machine boss on the 319. The HC simply bolts on. A balance wheel is what needs to be modified.